1. |
- Giang, Kok Wai, 1984, et al.
(author)
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Long-term trends in the prevalence of patients hospitalized with ischemic stroke from 1995 to 2010 in Sweden
- 2017
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 12:6
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Journal article (peer-reviewed)abstract
- Objective The prevalence of stroke is expected to increase partly because of prolonged life expectancy in the general population. The objective of this study was to investigate trends in the prevalence of patients hospitalized with ischemic stroke (IS) in Sweden from 1995-2010. The Swedish inpatient and cause-specific death registries were used to estimate the absolute numbers and prevalence of patients who were hospitalized with and survived an IS from 1995-2010. The overall number of IS increased from 129,418 in 1995 to 148,778 in 2010. In 1995, the prevalence of IS was 189 patients per 10,000 population. An increase in overall prevalence was observed until 2000, and then it remained stable, followed by a decline with an annual percentage change of (APC)-0.8% (95% CI -1.0 to 0.6) and with a final prevalence of 199 patients per 10,000 population in 2010. The prevalence of IS in people aged <45 years increased from 6.4 in 1995 to 7.6 patients per 10,000 population in 2010, with an APC of 2.1% (95% CI 0.9 to 3.4) from 1995-1998 and 0.7% (95% CI 0.6-0.9) from 1998-2010. Among those aged 45-54 years, the prevalence rose through the mid to late 1990s, followed by a slight decrease (APC:-0.7%, 95% CI -1.1 to -0.4) until 2006 and then remained stable with a prevalence of 43.8 patients per 10,000 population in 2010. Among >= 85 years, there was a minor decrease (APC: -0.3%, 95% CI -0.5 to -0.1) in overall prevalence after 2002 from 1481 to 1453 patients per 10,000 population in 2010. The overall prevalence of IS increased until 2000, but then remained stable followed by a slight decline. However, the prevalence of IS in the young increased through the study period. The absolute number of IS survivors has markedly increased, mainly because of demographic changes.
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2. |
- Giang, Kok Wai, 1984, et al.
(author)
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Trends in risk of recurrence after the first ischemic stroke in adults younger than 55 years of age in Sweden
- 2016
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In: International Journal of Stroke. - : SAGE Publications. - 1747-4930 .- 1747-4949. ; 11:1, s. 52-61
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Journal article (peer-reviewed)abstract
- Background: Previous studies on stroke recurrence in younger adults often contain small sample size which makes it difficult to study trends in stroke recurrence over a long period of time. Aims: The aim of the present study was to investigate temporal trends in the risk of recurrence in younger patients with a first ischemic stroke. Methods: All men and women aged 18-54 years who had survived at least 28 days after a first ischemic stroke from 1987 to 2006 were identified in the Swedish Inpatient Register. The patients were stratified into four 5-year periods according to their admission period and were followed up for a total of four years after the index event with regard to recurrent ischemic stroke. A Cox regression model was used to analyze the risk of recurrent ischemic stroke. Results: Of the 17,149 ischemic stroke patients who were identified, 2432 (14.2%) had a recurrent ischemic stroke event within four years. From the first to the last periods (1987-1991 versus 2002-2006), the four-year risk of recurrent ischemic stroke decreased by 55% (hazard ratio 0.45, 95% confidence interval 0.39-0.53) in men and 59% (hazard ratio 0.41, 95% confidence interval, 0.33-0.50) in women. The cumulative four-year risk was 11.8% (95% CI 10.55-13.25) in men and 9.8% (95% CI 8.40-11.46) in women during the last five-year period (2002-2006). Conclusions: The risk of recurrence among younger ischemic stroke patients has decreased over the past 20 years. Despite these improvements, younger patients are still at a high risk for recurrent ischemic stroke.
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5. |
- Redfors, Petra, et al.
(author)
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Living alone predicts mortality in patients with ischemic stroke before 70 years of age: a long-term prospective follow-up study
- 2016
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In: BMC neurology. - : Springer Science and Business Media LLC. - 1471-2377 .- 1471-2377. ; 16
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Journal article (peer-reviewed)abstract
- BACKGROUND: Living alone is associated with increased mortality after myocardial infarction but little data is available about whether this applies to prognosis after stroke. We aimed to examine the association between living situation and long-term mortality in patients with ischemic stroke and a control group, and to explore whether this association is modified by patient gender. METHODS: This is a prospective case-control study of 600 patients with ischemic stroke before 70 years of age and 600 age- and sex-matched controls who have been included in the Sahlgrenska Study on Ischemic Stroke. Mortality data were collected through national registers and medical records. We used Cox regression models for identifying predictors of mortality. RESULTS: In the entire sample, mean age was 57 years, proportion of males 64 %, proportion living alone 28 %, and median follow-up 8.6 years. Mortality rates were 36 % among patients living alone, 17 % among cohabitant patients, 15 % among controls living alone, and 9 % among cohabitant controls. Living alone was an independent predictor of all-cause mortality in cases after adjustment for stroke severity, stroke subtype, and vascular risk factors including physical activity, alcohol consumption, and socioeconomic status. A significant interaction was found between gender and living situation; the adjusted hazard ratio for mortality was 3.47 (95 % Confidence Interval 2.13-5.65) in male patients living alone, whereas no significant association was observed in women. Living alone was also a predictor of vascular mortality among cases and of all-cause mortality among controls. CONCLUSIONS: Living alone is associated with increased long-term mortality after ischemic stroke in men. Further prospective studies are needed to confirm the observed gender difference and to identify modifiable factors underlying this increased risk.
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6. |
- Åberg, N David, 1970, et al.
(author)
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Altered levels of circulating insulin-like growth factor I (IGF-I) following ischemic stroke are associated with outcome - a prospective observational study
- 2018
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In: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 18:1
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Journal article (peer-reviewed)abstract
- Background: Insulin-like growth factor I (IGF-I) has neuroprotective effects in experimental ischemic stroke (IS). However, in patients who have suffered IS, various associations between the levels of serum IGF-I (s-IGF-I) and clinical outcome have been reported, probably reflecting differences in sampling time-points and follow-up periods. Since changes in the levels of post-stroke s-IGF-I have not been extensively explored, we investigated whether decreases in the levels of s-IGF-I between the acute time-point (median, 4 days) and 3 months (Delta IGF-I, further transformed into Delta IGF-I-quintiles, Delta IGF-I-q) are associated with IS severity and outcome. Methods: In the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS) conducted in Gothenburg, Sweden, patients with IS who had s-IGF-I measurements available were included (N = 354; 65% males; mean age, 55 years). Baseline stroke severity was evaluated using the National Institutes of Health Stroke Scale (NIHSS) and converted into NIHSS-quintiles (NIHSS-q). Outcomes were assessed using the modified Rankin Scale (mRS) at 3 months and 2 years. Results: In general, the levels of s-IGF-I decreased (positive Delta IGF-I), except for those patients with the most severe NIHSS-q. After correction for sex and age, the 3rd Delta IGF-I-q showed the strongest association to mRS 0-2 [Odds Ratio (OR) 5.11, 95% confidence interval (CI) 2.18-11.9], and after 2 years, the 5th Delta IGF-I-q (OR 3.63, 95% CI 1.40-9.38) showed the strongest association to mRS 0-2. The associations remained significant after multivariate correction for diabetes, smoking, hypertension, and hyperlipidemia after 3 months, but were not significant (p = 0.057) after 2 years. The 3-month associations withstood additional correction for baseline stroke severity (p = 0.035), whereas the 2-year associations were further attenuated (p = 031). Conclusions: Changes in the levels of s-IGF-I are associated primarily with temporally near 3-month outcomes, while associations with long-term 2-year outcomes are weakened and attenuated by other factors. The significance of the change in post-stroke s-IGF-I is compatible with a positive role for IGF-I in IS recovery. However, the exact mechanisms are unknown and probably reflects combinations of multiple peripheral and central actions.
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7. |
- Abzhandadze, Tamar, 1980, et al.
(author)
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LIFE SATISFACTION IN SPOUSES OF STROKE SURVIVORS AND CONTROL SUBJECTS: A 7-YEAR FOLLOW-UP OF PARTICIPANTS IN THE SAHLGRENSKA ACADEMY STUDY ON ISCHAEMIC STROKE
- 2017
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In: Journal of Rehabilitation Medicine. - : Medical Journals Sweden AB. - 1650-1977. ; 49:7, s. 550-557
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Journal article (peer-reviewed)abstract
- Objective: To investigate life satisfaction in spouses of middle-aged stroke survivors from the long-term perspective and to identify factors that explain their life satisfaction. Subjects: Cohabitant spouses of survivors of ischaemic stroke aged < 70 years at stroke onset (n = 248) and spouses of controls (n = 246). Methods: Assessments were made 7 years after inclusion to the study. Spouses' life satisfaction was assessed with the Fugl-Meyer's Life Satisfaction Check-List (LiSAT 11). Stroke-related factors were examined with the National Institutes of Health stroke scale, Mini-Mental State Examination, Barthel Index and modified Rankin Scale. Results: Spouses of stroke survivors had significantly lower satisfaction with general life, leisure, sexual life, partner relationship, family life, and poorer somatic and psychological health than spouses of controls. Caregiving spouses had significantly lower scores on all life domains except vocation and own activities of daily living than non-caregiving spouses. Spouses' satisfaction on different life domains was explained mainly by their age, sex, support given to the partner, and the survivor's level of global disability, to which both physical and cognitive impairments contributed. Conclusion: Seven years after stroke, spouses of stroke survivors reported lower life satisfaction compared with spouses of controls. Life satisfaction in stroke survivors' spouses was associated with spouses' age, sex, giving support, and the stroke survivors' level of global disability.
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8. |
- Blomgren, Charlotte, et al.
(author)
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Long-term performance of instrumental activities of daily living (IADL) in young and middle-aged stroke survivors: Results from SAHLSIS outcome
- 2018
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In: Scandinavian Journal of Occupational Therapy. - : Informa UK Limited. - 1103-8128 .- 1651-2014. ; 25:2, s. 119-126
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Journal article (peer-reviewed)abstract
- Background: Although stroke prevalence is increasing and large proportions of stroke survivors are expected to live many years after stroke onset, research on the long-term consequences of stroke for instrumental activities of daily living (IADL) is limited. Aim: To explore performance of IADL seven years post-stroke onset and identify predictors of long-term IADL performance based on commonly employed acute measures and demographic characteristics in young and middle-aged stroke survivors. Methods: Data on stroke survivors were collected from SAHLSIS. IADL performance was assessed at 7 years using the Frenchay Activities Index (FAI). Demographic data and baseline measures were assessed as predictors of FAI outcome, using logistic regression. Results: 237 stroke survivors with a median age of 63 at follow-up were included. Participants had predominantly suffered a mild stroke and > 90% lived at home with no community services. Mean FAI was 25.7(score range 0-45), indicating reduced levels of participation in IADL. Frequency of performance of IADL was lowest for work/leisure activities. Gender, cohabitation status, initial stroke severity and baseline score on mRS were independently associated with IADL outcome. Conclusions: Reduced levels of participation in IADL persist many years after stroke onset and indicate a need to adapt a long-term perspective on stroke rehabilitation.
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9. |
- Blomgren, Charlotte, et al.
(author)
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Long-term performance of instrumental activities of daily living in young and middle-aged stroke survivors-Impact of cognitive dysfunction, emotional problems and fatigue.
- 2019
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In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 14:5
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Journal article (peer-reviewed)abstract
- With an upward trend in the number of people who return home to independent living after stroke, the ability to perform more complex activities is becoming an increasingly important long-term outcome after stroke. Although associations between Instrumental Activities of Daily Living (IADL) and cognitive dysfunction, emotional problems, and fatigue have been reported, less is known about the long-term impact of these stroke consequences on the performance of everyday activities in young and middle-aged stroke survivors.To explore the impact of cognitive dysfunction, emotional problems, and fatigue on long-term performance of instrumental activities of daily living in young and middle-aged stroke survivors.Data on stroke survivors, aged 18-69 at index stroke, were collected from the Sahlgrenska Academy Study on Ischaemic Stroke. IADL outcome was assessed using the Frenchay Activities Index (FAI), and the impact of chosen variables was assessed using Spearman´s rank-order correlation and logistic regression.Seven years after index stroke, 296 stroke survivors (median age of 64) were included in this study. Cognitive dysfunction showed the strongest correlations with FAI outcome and independently explained worse outcome on FAI summary score and the domain of work/leisure activities. Fatigue was independently explanatory of worse outcome on FAI summary score and domestic chores, while depressive symptoms independently explained worse outcome on work/leisure activities. In a subgroup with only those participants who had no or minimal residual neurological deficits at follow-up (NIHSS score 0), cognitive dysfunction independently explained worse outcome on FAI summary score and work/leisure activities. Depressive symptoms independently explained worse outcome on FAI summary score and domestic chores.Our results show that in young and middle-aged stroke survivors, cognitive dysfunction, depressive symptoms, and fatigue negatively impact performance of IADL even at seven years post stroke onset. Further, we have shown that an impact of both cognitive dysfunction and depressive symptoms can be found also among stroke survivors with mild or no remaining neurological deficits.
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10. |
- Chauhan, G., et al.
(author)
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Genetic and lifestyle risk factors for MRI-defined brain infarcts in a population-based setting
- 2019
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 92:5
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Journal article (peer-reviewed)abstract
- ObjectiveTo explore genetic and lifestyle risk factors of MRI-defined brain infarcts (BI) in large population-based cohorts.MethodsWe performed meta-analyses of genome-wide association studies (GWAS) and examined associations of vascular risk factors and their genetic risk scores (GRS) with MRI-defined BI and a subset of BI, namely, small subcortical BI (SSBI), in 18 population-based cohorts (n = 20,949) from 5 ethnicities (3,726 with BI, 2,021 with SSBI). Top loci were followed up in 7 population-based cohorts (n = 6,862; 1,483 with BI, 630 with SBBI), and we tested associations with related phenotypes including ischemic stroke and pathologically defined BI.ResultsThe mean prevalence was 17.7% for BI and 10.5% for SSBI, steeply rising after age 65. Two loci showed genome-wide significant association with BI: FBN2, p = 1.77 x 10(-8); and LINC00539/ZDHHC20, p = 5.82 x 10(-9). Both have been associated with blood pressure (BP)-related phenotypes, but did not replicate in the smaller follow-up sample or show associations with related phenotypes. Age- and sex-adjusted associations with BI and SSBI were observed for BP traits (p value for BI, p([BI]) = 9.38 x 10(-25); p([SSBI]) = 5.23 x 10(-14) for hypertension), smoking (p([BI]) = 4.4 x 10(-10); p([SSBI]) = 1.2 x 10(-4)), diabetes (p([BI]) = 1.7 x 10(-8); p([SSBI]) = 2.8 x 10(-3)), previous cardiovascular disease (p([BI]) = 1.0 x 10(-18); p([SSBI]) = 2.3 x 10(-7)), stroke (p([BI]) = 3.9 x 10(-69); p([SSBI]) = 3.2 x 10(-24)), and MRI-defined white matter hyperintensity burden (p([BI]) = 1.43 x 10(-157); p([SSBI]) = 3.16 x 10(-106)), but not with body mass index or cholesterol. GRS of BP traits were associated with BI and SSBI (p 0.0022), without indication of directional pleiotropy.ConclusionIn this multiethnic GWAS meta-analysis, including over 20,000 population-based participants, we identified genetic risk loci for BI requiring validation once additional large datasets become available. High BP, including genetically determined, was the most significant modifiable, causal risk factor for BI.
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11. |
- Cheng, Yu-Ching, et al.
(author)
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Genome-Wide Association Analysis of Young-Onset Stroke Identifies a Locus on Chromosome 10q25 Near HABP2.
- 2016
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In: Stroke; a journal of cerebral circulation. - 1524-4628. ; 47:2, s. 307-16
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Journal article (peer-reviewed)abstract
- Although a genetic contribution to ischemic stroke is well recognized, only a handful of stroke loci have been identified by large-scale genetic association studies to date. Hypothesizing that genetic effects might be stronger for early- versus late-onset stroke, we conducted a 2-stage meta-analysis of genome-wide association studies, focusing on stroke cases with an age of onset <60 years.
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12. |
- Cole, John W, et al.
(author)
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Genetics of the thrombomodulin-endothelial cell protein C receptor system and the risk of early-onset ischemic stroke.
- 2018
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In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 13:11
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Journal article (peer-reviewed)abstract
- Polymorphisms in coagulation genes have been associated with early-onset ischemic stroke. Here we pursue an a priori hypothesis that genetic variation in the endothelial-based receptors of the thrombomodulin-protein C system (THBD and PROCR) may similarly be associated with early-onset ischemic stroke. We explored this hypothesis utilizing a multi-stage design of discovery and replication.Discovery was performed in the Genetics-of-Early-Onset Stroke (GEOS) Study, a biracial population-based case-control study of ischemic stroke among men and women aged 15-49 including 829 cases of first ischemic stroke (42.2% African-American) and 850 age-comparable stroke-free controls (38.1% African-American). Twenty-four single-nucleotide-polymorphisms (SNPs) in THBD and 22 SNPs in PROCR were evaluated. Following LD pruning (r2≥0.8), we advanced uncorrelated SNPs forward for association analyses. Associated SNPs were evaluated for replication in an early-onset ischemic stroke population (onset-age<60 years) consisting of 3676 cases and 21118 non-stroke controls from 6 case-control studies. Lastly, we determined if the replicated SNPs also associated with older-onset ischemic stroke in the METASTROKE data-base.Among GEOS Caucasians, PROCR rs9574, which was in strong LD with 8 other SNPs, and one additional independent SNP rs2069951, were significantly associated with ischemic stroke (rs9574, OR = 1.33, p = 0.003; rs2069951, OR = 1.80, p = 0.006) using an additive-model adjusting for age, gender and population-structure. Adjusting for risk factors did not change the associations; however, associations were strengthened among those without risk factors. PROCR rs9574 also associated with early-onset ischemic stroke in the replication sample (OR = 1.08, p = 0.015), but not older-onset stroke. There were no PROCR associations in African-Americans, nor were there any THBD associations in either ethnicity.PROCR polymorphisms are associated with early-onset ischemic stroke in Caucasians.
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- Debette, Stéphanie, et al.
(author)
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Common variation in PHACTR1 is associated with susceptibility to cervical artery dissection
- 2015
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 47, s. 78-83
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Journal article (peer-reviewed)abstract
- Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year)1. Minor cervical traumas, infection, migraine and hypertension are putative risk factors1–3, and inverse associations with obesity and hypercholesterolemia are described3,4. No confirmed genetic susceptibility factors have been identified using candidate gene approaches5. We performed genome-wide association studies (GWAS) in 1 1,393 CeAD cases and 1 14,416 controls. The rs9349379[G] allele (PHACTR1) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69–0.82; P = 4.46 × 1 10−10), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 1 × 1 10−3; combined P = 1 1.00 × 1 10−1111). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction6–9. Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions.
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- Ekblom, Maria, 1974-, et al.
(author)
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Device-Measured Sedentary Behavior, Physical Activity and Aerobic Fitness Are Independent Correlates of Cognitive Performance in Healthy Middle-Aged Adults-Results from the SCAPIS Pilot Study.
- 2019
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In: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 16:24
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Journal article (peer-reviewed)abstract
- High aerobic fitness, more moderate to vigorous physical activity (MVPA) and less sedentary behavior (SED) have all been suggested to promote cognitive functions, but it is unclear whether they are independent predictors of specific cognitive domains. This study aimed to investigate to what extent aerobic fitness MVPA and SED are independently associated with cognitive performance among middle-aged Swedish adults. We acquired device-based measures of aerobic fitness, cognitive performance and percent daily time spent in MVPA and SED in Swedish adults (n = 216; 54-66 years old). Aerobic fitness was associated with better performance at one out of two tests of speed/attention and one out of four tests of executive attention, and with worse performance at one of seven tests of memory. Increasing %MVPA was associated with better performance at one out of seven tests of memory and two out of three tests of verbal ability, whereas increasing %SED was associated with better performance at all four tests of executive attention and four out of seven tests of memory. These findings suggest that aerobic fitness, %MVPA and %SED are partly independent correlates of cognitive performance. To fully understand the association between SED and performance at several tests of cognitive function, future investigations might attempt to investigate intellectually engaging SED (such as reading books) separately from mentally undemanding SED (such as watching TV).
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15. |
- Ekker, Merel, et al.
(author)
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Global Outcome Assessment Life-long after stroke in young adults initiative-the GOAL initiative: study protocol and rationale of a multicentre retrospective individual patient data meta-analysis.
- 2019
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In: BMJ open. - : BMJ. - 2044-6055. ; 9:11
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Journal article (peer-reviewed)abstract
- Worldwide, 2 million patients aged 18-50 years suffer a stroke each year, and this number is increasing. Knowledge about global distribution of risk factors and aetiologies, and information about prognosis and optimal secondary prevention in young stroke patients are limited. This limits evidence-based treatment and hampers the provision of appropriate information regarding the causes of stroke, risk factors and prognosis of young stroke patients.The Global Outcome Assessment Life-long after stroke in young adults (GOAL) initiative aims to perform a global individual patient data meta-analysis with existing data from young stroke cohorts worldwide. All patients aged 18-50 years with ischaemic stroke or intracerebral haemorrhage will be included. Outcomes will be the distribution of stroke aetiology and (vascular) risk factors, functional outcome after stroke, risk of recurrent vascular events and death and finally the use of secondary prevention. Subgroup analyses will be made based on age, gender, aetiology, ethnicity and climate of residence.Ethical approval for the GOAL study has already been obtained from the Medical Review Ethics Committee region Arnhem-Nijmegen. Additionally and when necessary, approval will also be obtained from national or local institutional review boards in the participating centres. When needed, a standardised data transfer agreement will be provided for participating centres. We plan dissemination of our results in peer-reviewed international scientific journals and through conference presentations. We expect that the results of this unique study will lead to better understanding of worldwide differences in risk factors, causes and outcome of young stroke patients.
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16. |
- Fava, Cristiano, et al.
(author)
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A genetic risk score for hypertension associates with the risk of ischemic stroke in a Swedish case-control study
- 2015
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In: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 23, s. 969-974
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Journal article (peer-reviewed)abstract
- Genetic risk scores (GRS), summing up the total effect of several single-nucleotide polymorphisms (SNPs) in genes associated with either coronary risk or cardiovascular risk factors, have been tested for association with ischemic stroke with conflicting results. Recently an association was found between a GRS based on 29 SNPs discovered by genome-wide association studies and hypertension. The aim of our study was to investigate the possible association of the same GRS with ischemic stroke on top of other ‘traditional risk factors’, also testing its potential improvement in indices of discrimination and reclassification, in a Swedish case–control study. Twenty-nine SNPs were genotyped in 3677 stroke cases and 2415 controls included in the Lund Stroke Register (LSR), the Malmö Diet and Cancer (MDC) study and the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). The analysis was conducted in the combined sample, and separately for the three studies. After adjustment for hypertension, diabetes mellitus and smoking habits, the GRS was associated with ischemic stroke in the combined sample (OR (95% CI) 1.086 (1.029–1.147) per SD increase in the GRS P=0.003) with similar trends in all three samples: LSR (1.050 (0.967–1.140); P=0.25), MDC (1.168 (1.060–1.288); P=0.002) and SAHLSIS (1.124 (0.997–1.267); P=0.055). Measures of risk discrimination and reclassification improved marginally using the GRS. A blood pressure GRS is independently associated with ischemic stroke risk in three Swedish case–control studies, however, the effect size is low and adds marginally to prediction of stroke on top of traditional risk factors including hypertension.
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17. |
- Franceschini, N., et al.
(author)
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GWAS and colocalization analyses implicate carotid intima-media thickness and carotid plaque loci in cardiovascular outcomes
- 2018
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
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Journal article (peer-reviewed)abstract
- Carotid artery intima media thickness (cIMT) and carotid plaque are measures of subclinical atherosclerosis associated with ischemic stroke and coronary heart disease (CHD). Here, we undertake meta-analyses of genome-wide association studies (GWAS) in 71,128 individuals for cIMT, and 48,434 individuals for carotid plaque traits. We identify eight novel susceptibility loci for cIMT, one independent association at the previously-identified PINX1 locus, and one novel locus for carotid plaque. Colocalization analysis with nearby vascular expression quantitative loci (cis-eQTLs) derived from arterial wall and metabolic tissues obtained from patients with CHD identifies candidate genes at two potentially additional loci, ADAMTS9 and LOXL4. LD score regression reveals significant genetic correlations between cIMT and plaque traits, and both cIMT and plaque with CHD, any stroke subtype and ischemic stroke. Our study provides insights into genes and tissue-specific regulatory mechanisms linking atherosclerosis both to its functional genomic origins and its clinical consequences in humans. © 2018, The Author(s).
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20. |
- Gerafi, Joel, et al.
(author)
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Neglect and aphasia in the acute phase as predictors of functional outcome 7 years after ischemic stroke
- 2017
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In: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 24:11, s. 1407-1415
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Journal article (peer-reviewed)abstract
- © 2017 EAN Background and purpose: Visuospatial inattention (VSI) and language impairment (LI) are often present early after stroke and associations with an unfavorable short-term functional outcome have been reported. The purpose of this study was to investigate whether a screening of VSI and LI as indicators of cortical symptoms early after stroke could predict long-term functional outcomes. Methods: A consecutive cohort of 375 patients with ischemic stroke was assessed for the occurrence of VSI at a median of 7 days after admission (interquartile range, 1–5 days) using the Star Cancellation Test and for LI (within the first 7 days) with the language item in the Scandinavian Stroke Scale. Seven years later, functional outcomes were assessed by the modified Rankin scale and Frenchay Activities Index in 235 survivors without recurrent stroke. Relationships between baseline predictors and functional outcome at 7 years were analyzed with bivariate correlations and multiple categorical regressions with optimal scaling. Results: The regression model significantly explained variance in the modified Rankin scale (R 2 = 0.435, P < 0.001) and identified VSI (P = 0.001) and neurological deficits (P < 0.001; Scandinavian Stroke Scale score without the language item) as the significant independent predictors. The model for Frenchay Activities Index was also significant (R 2 = 0.269, P < 0.001) with VSI (P = 0.035) and neurological deficits (P < 0.001) as significant independent predictors. Conclusions: Visuospatial inattention at acute stroke has an independent impact on long-term functional outcomes. Early recognition may enable targeted rehabilitative interventions.
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22. |
- Giese, A. K., et al.
(author)
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Design and rationale for examining neuroimaging genetics in ischemic stroke The MRI-GENIE study
- 2017
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In: Neurology-Genetics. - : Ovid Technologies (Wolters Kluwer Health). - 2376-7839. ; 3:5
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Journal article (peer-reviewed)abstract
- Objective: To describe the design and rationale for the genetic analysis of acute and chronic cerebrovascular neuroimaging phenotypes detected on clinical MRI in patients with acute ischemic stroke (AIS) within the scope of the MRI-GENetics Interface Exploration (MRI-GENIE) study.& para;& para;Methods: MRI-GENIE capitalizes on the existing infrastructure of the Stroke Genetics Network (SiGN). In total, 12 international SiGN sites contributed MRIs of 3,301 patients with AIS. Detailed clinical phenotyping with the web-based Causative Classification of Stroke (CCS) system and genome-wide genotyping data were available for all participants. Neuroimaging analyses include the manual and automated assessments of established MRI markers. A high-throughput MRI analysis pipeline for the automated assessment of cerebrovascular lesions on clinical scans will be developed in a subset of scans for both acute and chronic lesions, validated against gold standard, and applied to all available scans. The extracted neuroimaging phenotypes will improve characterization of acute and chronic cerebrovascular lesions in ischemic stroke, including CCS subtypes, and their effect on functional outcomes after stroke. Moreover, genetic testing will uncover variants associated with acute and chronic MRI manifestations of cerebrovascular disease.& para;& para;Conclusions: The MRI-GENIE study aims to develop, validate, and distribute the MRI analysis platform for scans acquired as part of clinical care for patients with AIS, which will lead to (1) novel genetic discoveries in ischemic stroke, (2) strategies for personalized stroke risk assessment, and (3) personalized stroke outcome assessment.
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23. |
- Gill, D., et al.
(author)
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Genetically Determined Risk of Depression and Functional Outcome After Ischemic Stroke: Mendelian Randomization Study
- 2019
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In: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 50:8, s. 2219-2222
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Journal article (peer-reviewed)abstract
- Background and Purpose- Psychosocial factors can have implications for ischemic stroke risk and recovery. This study investigated the effect of genetically determined risk of depression on these outcomes using the Mendelian randomization (MR) framework. Methods- Genetic instruments for risk of depression were identified in a discovery genome-wide association study of 246363 cases and 561190 controls and further replicated in a separate population of 474574 cases and 1032579 controls. Corresponding genetic association estimates for risk of ischemic stroke were taken from 60341 cases and 454450 controls, with those for functional outcome 3 months after ischemic stroke taken from an analysis of 6021 patients. Following statistical power calculation, inverse-variance weighted MR was performed to pool estimates across different instruments. The Cochran Q heterogeneity test, weighted median MR, and MR pleiotropy residual sum and outlier were used to explore possible bias relating to inclusion of pleiotropic variants. Results- There was no MR evidence for an effect of genetically determined risk of depression on ischemic stroke risk. Although suffering low statistical power, the main inverse-variance weighted MR analysis was suggestive of a detrimental effect of genetically determined risk of depression on functional outcome after ischemic stroke (odds ratio of poor outcome [modified Rankin Scale, >= 3] per 1-SD increase in genetically determined risk of depression, 1.81; 95% CI, 0.98-3.35; P=0.06). There was no evidence of heterogeneity between MR estimates produced by different instruments (Q P=0.26). Comparable MR estimates were obtained with weighted median MR (odds ratio, 2.57; 95% CI, 1.05-6.25; P=0.04) and MR pleiotropy residual sum and outlier (odds ratio, 1.81; 95% CI, 0.95-3.46; P=0.08). Conclusions- We found no MR evidence of genetically determined risk of depression affecting ischemic stroke risk but did find consistent MR evidence suggestive of a possible effect on functional outcome after ischemic stroke. Given the widespread prevalence of depression-related morbidity, these findings could have implications for prognostication and personalized rehabilitation after stroke.
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24. |
- Holmegaard, Lukas, et al.
(author)
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Long-term progression of white matter hyperintensities in ischemic stroke
- 2018
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In: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314. ; 138:6, s. 548-556
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Journal article (peer-reviewed)abstract
- Objectives Studies on long-term progression of white matter hyperintensities (WMH) after ischemic stroke are scarce. Here, we sought to investigate this progression and its predictors in a cohort presenting with ischemic stroke before 70 years of age. Materials and methods Participants in the Sahlgrenska Academy Study on Ischemic Stroke who underwent magnetic resonance imaging (MRI) of the brain at index stroke were examined by MRI again after 7 years (n = 188, mean age 53 years at index stroke, 35% females). WMH at index stroke and progression were assessed according to Fazekas' grades and the WMH change scale. Stroke subtype was classified according to TOAST. Results Marked WMH at index stroke were present in 20% of the participants and were significantly associated with age, hypertension, and subtype. Progression of WMH after 7 years was observed in 63% and 35% of the participants for subcortical and periventricular locations, respectively. Significant independent predictors of progression were age and marked WMH at baseline for both locations, whereas no significant associations were detected for vascular risk factors or subtype in multivariable analyses. In participants with no or only mild WMH at baseline, 20% showed marked WMH at follow-up. Age and hypertension, but not subtype, were independently associated with this acquisition of marked WMH. Conclusions Age and marked WMH at index stroke, but not stroke subtype, predicted long-term WMH progression after ischemic stroke before 70 years of age, whereas age and hypertension predicted acquisition of marked WMH in those with no or only mild WMH at baseline.
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25. |
- Lagging, Cecilia, et al.
(author)
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APOE ε4 is associated with younger age at ischemic stroke onset but not with stroke outcome
- 2019
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In: Neurology. - 1526-632X. ; 93:19, s. 849-853
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Journal article (peer-reviewed)abstract
- Stroke outcome is determined by a complex interplay, where age and stroke severity are predominant predictors. Studies on hemorrhagic stroke indicate that APOE genotype is a predictor of poststroke outcomes,1,2 but results from studies on ischemic stroke are more conflicting.1,3 There is 1 study suggesting an influence of APOE genotype on age at ischemic stroke onset,4 and sex-specific effects on outcome have been reported.5 Taken together, there is a need for larger studies on APOE and ischemic stroke outcomes with integrated information on age, severity, and sex.The 3 common APOE alleles ε2, ε3, and ε4 can be separated by a combination of 2 single nucleotide polymorphisms (SNPs), rs429358 and rs7412. Thus, associations with APOE alleles are not directly captured in a regular genome-wide association study (GWAS), where each SNP is investigated separately. We derived the 3 common APOE alleles and investigated the interplay between APOE, age at ischemic stroke onset, severity, sex, and outcome within a large international collaboration, the Genetics of Ischaemic Stroke Functional Outcome (GISCOME) network.
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26. |
- Larsson, S. C., et al.
(author)
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Serum magnesium and calcium levels in relation to ischemic stroke: Mendelian randomization study
- 2019
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In: Neurology. - 1526-632X .- 0028-3878. ; 92:9
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To determine whether serum magnesium and calcium concentrations are causally associated with ischemic stroke or any of its subtypes using the mendelian randomization approach. METHODS: Analyses were conducted using summary statistics data for 13 single-nucleotide polymorphisms robustly associated with serum magnesium (n = 6) or serum calcium (n = 7) concentrations. The corresponding data for ischemic stroke were obtained from the MEGASTROKE consortium (34,217 cases and 404,630 noncases). RESULTS: In standard mendelian randomization analysis, the odds ratios for each 0.1 mmol/L (about 1 SD) increase in genetically predicted serum magnesium concentrations were 0.78 (95% confidence interval [CI] 0.69-0.89; p = 1.3 × 10-4) for all ischemic stroke, 0.63 (95% CI 0.50-0.80; p = 1.6 × 10-4) for cardioembolic stroke, and 0.60 (95% CI 0.44-0.82; p = 0.001) for large artery stroke; there was no association with small vessel stroke (odds ratio 0.90, 95% CI 0.67-1.20; p = 0.46). Only the association with cardioembolic stroke was robust in sensitivity analyses. There was no association of genetically predicted serum calcium concentrations with all ischemic stroke (per 0.5 mg/dL [about 1 SD] increase in serum calcium: odds ratio 1.03, 95% CI 0.88-1.21) or with any subtype. CONCLUSIONS: This study found that genetically higher serum magnesium concentrations are associated with a reduced risk of cardioembolic stroke but found no significant association of genetically higher serum calcium concentrations with any ischemic stroke subtype. Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.
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27. |
- Maguire, Jane M., et al.
(author)
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GISCOME – Genetics of Ischaemic Stroke Functional Outcome network : A protocol for an international multicentre genetic association study
- 2017
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In: European Stroke Journal. - : SAGE Publications. - 2396-9873 .- 2396-9881. ; 2:3, s. 229-237
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Journal article (peer-reviewed)abstract
- Introduction: Genome-wide association studies have identified several novel genetic loci associated with stroke risk, but how genetic factors influence stroke outcome is less studied. The Genetics of Ischaemic Stroke Functional outcome network aims at performing genetic studies of stroke outcome. We here describe the study protocol and methods basis of Genetics of Ischaemic Stroke Functional outcome. Methods: The Genetics of Ischaemic Stroke Functional outcome network has assembled patients from 12 ischaemic stroke projects with genome-wide genotypic and outcome data from the International Stroke Genetics Consortium and the National Institute of Neurological Diseases Stroke Genetics Network initiatives. We have assessed the availability of baseline variables, outcome metrics and time-points for collection of outcome data. Results: We have collected 8831 ischaemic stroke cases with genotypic and outcome data. Modified Rankin score was the outcome metric most readily available. We detected heterogeneity between cohorts for age and initial stroke severity (according to the NIH Stroke Scale), and will take this into account in analyses. We intend to conduct a first phase genome-wide association outcome study on ischaemic stroke cases with data on initial stroke severity and modified Rankin score within 60–190 days. To date, we have assembled 5762 such cases and are currently seeking additional cases meeting these criteria for second phase analyses. Conclusion: Genetics of Ischaemic Stroke Functional outcome is a unique collection of ischaemic stroke cases with detailed genetic and outcome data providing an opportunity for discovery of genetic loci influencing functional outcome. Genetics of Ischaemic Stroke Functional outcome will serve as an exploratory study where the results as well as the methodological observations will provide a basis for future studies on functional outcome. Genetics of Ischaemic Stroke Functional outcome can also be used for candidate gene replication or assessing stroke outcome non-genetic association hypotheses.
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28. |
- Mola-Caminal, M., et al.
(author)
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PATJ Low Frequency Variants Are Associated With Worse Ischemic Stroke Functional Outcome A Genome-Wide Meta-Analysis
- 2019
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In: Circulation research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7330 .- 1524-4571. ; 124:1, s. 114-120
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Journal article (peer-reviewed)abstract
- Rationale: Ischemic stroke is among the leading causes of adult disability. Part of the variability in functional outcome after stroke has been attributed to genetic factors but no locus has been consistently associated with stroke outcome. Objective: Our aim was to identify genetic loci influencing the recovery process using accurate phenotyping to produce the largest GWAS (genome-wide association study) in ischemic stroke recovery to date. Methods and Results: A 12-cohort, 2-phase (discovery-replication and joint) meta-analysis of GWAS included anterior-territory and previously independent ischemic stroke cases. Functional outcome was recorded using 3-month modified Rankin Scale. Analyses were adjusted for confounders such as discharge National Institutes of Health Stroke Scale. A gene-based burden test was performed. The discovery phase (n=1225) was followed by open (n=2482) and stringent joint-analyses (n=1791). Those cohorts with modified Rankin Scale recorded at time points other than 3-month or incomplete data on previous functional status were excluded in the stringent analyses. Novel variants in PATJ (Pals1-associated tight junction) gene were associated with worse functional outcome at 3-month after stroke. The top variant was rs76221407 (G allele, beta=0.40, P=1.70x10-9). Conclusions: Our results identify a set of common variants in PATJ gene associated with 3-month functional outcome at genome-wide significance level. Future studies should examine the role of PATJ in stroke recovery and consider stringent phenotyping to enrich the information captured to unveil additional stroke outcome loci.
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29. |
- Ohlsson, Claes, 1965, et al.
(author)
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BMI increase through puberty and adolescence is associated with risk of adult stroke
- 2017
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 89:4, s. 363-369
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Journal article (peer-reviewed)abstract
- Objective: To evaluate the contribution of prepubertal childhood body mass index (BMI) and BMI change through puberty and adolescence, 2 distinct developmental BMI parameters, for risk of adult stroke in men. Methods: In this population-based study in Gothenburg, Sweden, men born in 1945-1961 with information on both childhood BMI at age 8 and BMI change through puberty and adolescence (BMI at age 20-BMI at age 8) were followed until December 2013 (n = 37,669). Information on stroke events was retrieved from high-quality national registers (918 first stroke events, 672 ischemic stroke events [IS], 207 intracerebral hemorrhage events [ICH]). Results: BMI increase through puberty and adolescence (hazard ratio [HR] 1.21 per SD increase; 95% confidence interval [CI] 1.14-1.28), but not childhood BMI, was independently associated with risk of adult stroke. Subanalyses revealed that BMI increase through puberty and adolescence was associated with both IS (HR per SD increase 1.19; 95% CI 1.11-1.28) and ICH (HR per SD increase 1.29; 95% CI 1.15-1.46). High BMI increase during puberty was strongly associated with increased risk of adult hypertension (odds ratio per SD increase 1.35; 95% CI 1.32-1.39). Conclusions: BMI increase through puberty and adolescence is associated with risk of adult IS and ICH in men. We propose that greater BMI increases during puberty contribute to increased risk of adult stroke at least partly via increased blood pressure.
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30. |
- Ohlsson, T., et al.
(author)
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A stop-codon of the phosphodiesterase 11A gene is associated with elevated blood pressure and measures of obesity
- 2016
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In: Journal of Hypertension. - : Ovid Technologies (Wolters Kluwer Health). - 0263-6352. ; 34:3, s. 445-451
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Journal article (peer-reviewed)abstract
- Objective:To identify stop-codon variants associated with blood pressure (BP).Methods:Illumina exome chip was genotyped in 5453 individuals of the population-based Malmo Diet and Cancer Study. We compared BP levels between carriers and noncarriers of all stop-codon variants found in at least 10 individuals and characterized these further based on literature evidence of functionality. Next, the association to ischemic stroke was evaluated in 2278 cases of ischemic stroke and 5969 controls.Results:We identified 19 stop-codon variants with nominally significant BP associations (P<0.05). One of these, located in the phosphodiesterase 11A (PDE11A) gene (R307X), has previously been reported to cause loss of PDE11A function and Cushing's syndrome in female carriers. In the Malmo Diet and Cancer Study, 1% of the population carried R307X and had age and sex-adjusted (mean, 95% confidence interval) 5.0, 0.29-9.7 (P=0.038), and 3.3, 0.83-5.7 (P=0.009) mmHg higher SBP and DBP than noncarriers and also significantly higher waist circumference and BMI. Among females, carriers of the R307X had age adjusted 8.3, 2.3-14 (P=0.006) and 4.7, 1.7-7.7 (P=0.002) mmHg higher SBP and DBP, 4.3, 0.84-7.8 (P=0.015)cm higher waist circumference and 1.7, 0.30-3.1 (P=0.018)kg/m(2) higher BMI. In addition, carriers of the R307X mutation had an odds ratio of ischemic stroke of 1.73 (95% confidence interval 1.06-2.82); P=0.028.Conclusion:One percent of the Swedish population carries a PDE11A loss-of-function mutation associated with elevated BP, abdominal obesity, and risk of ischemic stroke.
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31. |
- Olsson Lindvall, Martina, et al.
(author)
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Hemostatic Genes Exhibit a High Degree of Allele-Specific Regulation in Liver
- 2019
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In: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 119:7, s. 1072-1083
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Journal article (peer-reviewed)abstract
- Objective Elucidating the genetic basis underlying hepatic hemostatic gene expression variability may contribute to unraveling genetic factors contributing to thrombotic or bleeding disorders. We aimed to identify novel cis-regulatory variants involved in regulating hemostatic genes by analyzing allele-specific expression (ASE) in human liver samples. Study Design Biopsies of human liver tissue and blood were collected from adults undergoing liver surgery at the Sahlgrenska University Hospital (n =20). Genomic deoxyribonucleic acid (gDNA) and total ribonucleic acid (RNA) were isolated. A targeted approach was used to enrich and sequence 35 hemostatic genes for single nucleotide polymorphism (SNP) analysis (gDNAseq) and construct individualized genomes for transcript alignment. The allelic ratio of transcripts from targeted RNAseq was determined via ASE analysis. Public expression quantitative trait loci (eQTL) and genome-wide association study (GWAS) data were used to assess novelty and importance of the ASE SNPs (and proxies, r(2) >= 0.8) for relevant traits/diseases. Results Sixty percent of the genes studied showed allelic imbalance across 53 SNPs. Of these, 7 SNPs were previously validated in liver eQTL studies. For 32 with eQTLs in other cell/tissue types, this is the first time genotype-specific expression is demonstrated in liver, and for 14 ASE SNPs, this is the first ever reported genotype-expression association. A total of 29 ASE SNPs were previously associated with the respective plasma protein levels and 17 ASE SNPs to other relevant GWAS traits including venous thromboembolism, coronary artery disease, and stroke. Conclusion Our study provides a comprehensive ASE analysis of hemostatic genes and insights into the regulation of hemostatic genes in human liver.
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32. |
- Olsson, Martina, et al.
(author)
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Epigenetic Regulation of Tissue-Type Plasminogen Activator in Human Brain Tissue and Brain-Derived Cells
- 2016
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In: Gene Regulation and Systems Biology. - 1177-6250. ; 10, s. 9-13
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Journal article (peer-reviewed)abstract
- The serine protease tissue-type plasminogen activator (t-PA) is involved in both vital physiological brain processes, such as synaptic plasticity, and pathophysiological conditions, such as neurodegeneration and ischemic stroke. Recent data suggest that epigenetic mechanisms play an important role in the regulation of t-PA in human endothelial cells. However, there are limited data on epigenetic regulation of t-PA in human brain-derived cells. We demonstrate that treatment of cultured human neurons and human astrocytes with the histone deacetylase inhibitors trichostatin A (TSA) and MS-275 resulted in a two- to threefold increase in t-PA mRNA and protein expression levels. Next, we performed a chromatin immunoprecipitation assay on treated astrocytes with antibodies directed against acetylated histones H3 and H4 (both markers of gene activation). Treatment with MS-275 and TSA for 24 hours resulted in a significant increase in H3 acetylation, which could explain the observed increase in t-PA gene activity after the inhibition of histone deacety-lation. Furthermore, DNA methylation analysis of cultured human neurons and astrocytes, as well as human postmortem brain tissue, revealed a stretch of unmethylated CpG dinucleotides in the proximal t-PA promoter, whereas more upstream CpGs were highly methylated. Taken together, these results implicate involvement of epigenetic mechanisms in the regulation of t-PA expression in the human brain.
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33. |
- Olsson, Maja, 1975, et al.
(author)
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Genome-wide analysis of genetic determinants of circulating factorVII-activating protease (FSAP) activity
- 2018
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In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 16:10, s. 2024-2034
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Journal article (peer-reviewed)abstract
- Background FactorVII-activating protease (FSAP) has roles in both coagulation and fibrinolysis. Recent data indicate its involvement in several other processes, such as vascular remodeling and inflammation. Plasma FSAP activity is highly variable among healthy individuals and, apart from the low-frequency missense variant Marburg-I (rs7080536) in the FSAP-encoding gene HABP2, determinants of this variation are unclear. Objectives To identify novel genetic variants within and outside of the HABP2 locus that influence circulating FSAP activity. Patients/Methods We performed an exploratory genome-wide association study (GWAS) on plasma FSAP activity amongst 3230 Swedish subjects. Directly genotyped rare variants were also analyzed with gene-based tests. Using GWAS, we confirmed the strong association between the Marburg-I variant and FSAP activity. HABP2 was also significant in the gene-based analysis, and remained significant after exclusion of Marburg-I carriers. This was attributable to a rare HABP2 stop variant (rs41292628). Carriers of this stop variant showed a similar reduction in FSAP activity as Marburg-I carriers, and this finding was replicated. A secondary genome-wide significant locus was identified at a 5p15 locus (rs35510613), and this finding requires future replication. This common variant is located upstream of ADCY2, which encodes a protein catalyzing the formation of cAMP. Results and Conclusions This study verified the Marburg-I variant to be a strong regulator of FSAP activity, and identified an HABP2 stop variant with a similar impact on FSAP activity. A novel locus near ADCY2 was identified as a potential additional regulator of FSAP activity.
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34. |
- Pedersen, Annie, 1981, et al.
(author)
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Circulating neurofilament light in ischemic stroke: temporal profile and outcome prediction
- 2019
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In: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 266:11, s. 2796-2806
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Journal article (peer-reviewed)abstract
- Background and purpose Neurofilament light chain (NfL) is a marker of neuroaxonal damage. We aimed to study associations between serum NfL (sNfL) concentrations at different time points after ischemic stroke and outcomes. Methods We prospectively included ischemic stroke cases (n=595, mean age 59 years, 64% males) and assessed outcomes by both the modified Rankin Scale (mRS) and the NIH stroke scale (NIHSS) at 3 months and by mRS at 2 years. In a subsample, long-term (7-year) outcomes were also assessed by both mRS and NIHSS. We used the ultrasensitive single-molecule array assay to measure sNfL in the acute phase (range 1–14, median 4 days), after 3 months and 7 years in cases and once in controls (n=595). Results Acute-phase sNfL increased by the time to blood-draw and highest concentrations were observed at 3 months post-stroke. High sNfL associated to stroke severity and poor outcomes, and both associations were strongest for 3-month sNfL. After adjusting for age, previous stroke, stroke severity, and day of blood draw, 3-month sNfL was significantly associated to both outcomes at all time points (p<0.01 throughout). For all main etiological subtypes, both acute phase and 3-month sNfL were significantly higher than in controls, but the dynamics of sNfL differed by stroke subtype. Conclusions The results from this study inform on sNfL in ischemic stroke and subtypes over time, and show that sNfL predicts short- and long-term neurological and functional outcomes. Our findings suggest a potential utility of sNfL in ischemic stroke outcome prediction.
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35. |
- Pedersen, Annie, 1981, et al.
(author)
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Fibrinogen concentrations predict long-term cognitive outcome in young ischemic stroke patients
- 2018
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In: Research and Practice in Thrombosis and Haemostasis. - : Elsevier BV. - 2475-0379. ; 2:2, s. 339-346
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Journal article (peer-reviewed)abstract
- Background: Cognitive impairment is frequent after stroke, and young patients may live with this consequence for a long time. Predictors of cognitive outcomes after stroke represent a current gap of knowledge. Objectives: To investigate levels of three hemostatic biomarkers as predictors of long-term cognitive function after stroke. Methods: This longitudinal study included consecutively recruited patients with ischemic stroke at 18-69 years (n = 268). Blood was collected 3 months after index stroke and analyzed for plasma concentrations of fibrinogen, von Willebrand factor (VWF) and tissue-type plasminogen activator (t-PA) antigen. Cognitive function 7 years after index stroke was assessed by the Barrow Neurological Institute Screen for Higher Cerebral Functions (BNIS). Participants with stroke <50 years of age were also examined by the Trail Making Test A and B (n = 41). Associations between biomarker concentrations and cognitive scales were assessed in the whole group and in participants with stroke <50 years of age. Results: The hemostatic biomarkers fibrinogen, VWF and t-PA, were all correlated to total BNIS score, but these associations did not withstand adjustment for confounding factors in the whole group. However, in patients <50 years, we found an independent association between fibrinogen concentrations and total BNIS score (beta(std) = -.27, 95% confidence interval [CI], -0.47 to -0.07) and to performance on the Trail Making Test A (beta(std) = 31, 95% CI, 0.03-0.58). No such association was seen for the Trail Making Test B. Conclusion: High convalescent fibrinogen concentrations were associated with worse long-term cognitive outcomes in ischemic stroke <50 years of age. We propose further investigations of fibrinogen in relation to cognitive function in stroke in the young.
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36. |
- Pedersen, Annie, 1981, et al.
(author)
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Haemostatic biomarkers are associated with long-term recurrent vascular events after ischaemic stroke
- 2016
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In: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 116:3, s. 537-543
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Journal article (peer-reviewed)abstract
- Ischaemic stroke patients continue to be at risk for recurrent vascular events for many years. Predictors of long-term prognosis are needed. It was the objective of this study to investigate levels of four haemostatic proteins as long-term predictors of recurrent vascular events after ischaemic stroke. We prospectively followed 548 ischaemic stroke patients, 18-69 years, and registered recurrent vascular events. Plasma levels of tissue-type plasminogen activator (t-PA), von Willebrand factor (VWF), fibrinogen and thrombin activatable fibrinolysis inhibitor activation peptide (TAFI-AP) were measured three months after index stroke. Cox regression models were used to assess associations to outcomes for single biomarkers and for a combined biomarker measure. For single biomarkers significantly associated with any of the outcomes, we performed subanalyses stratified for age, sex, diabetes and atherosclerosis. During 5,637 person-years of follow-up, we registered 74 vascular deaths, 90 recurrent strokes and 62 coronary events. Levels of t-PA, VWF and fibrinogen were significantly associated with vascular death and coronary events. After adjustment, the association between t-PA and vascular death remained (HR per 1 SD increase in plasma level 1.27, 95 % CI 1.00-1.61, p=0.047). The combined effect of t-PA, VWF and fibrinogen was associated with coronary events (adjusted HR 1.35, 1.02-1.80, p=0.04). In non-diabetic patients, an association with coronary events was seen for VWF levels (adjusted HR 2.23,1.45-3.43, p
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37. |
- Persson, Josefine, 1981, et al.
(author)
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Long- term cost of spouses’ informal support for dependent midlife stroke survivors
- 2017
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In: Brain and Behavior. - : Wiley. - 2162-3279. ; 7:6
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Journal article (peer-reviewed)abstract
- Objectives: Stroke is a major global disease that requires extensive care and support from society and relatives. The aim of this study was to identify and quantify the long- term informal support and to estimate the annual cost of informal support provided by spouses to their stroke surviving partner. Method: Data were based on the 7- year follow- up of the Sahlgrenska Academy Study on Ischemic Stroke. One- third of the spouses stated that they provided support to their stroke surviving partner. The magnitude of the support was assessed with a study- specific time- diary and was estimated for independent and dependent stroke survivors based on the scores of the modified Rankin Scale. To deal with skewed data, a two- part econometric model was used to estimate the annual cost of informal support. Result: Cohabitant dyads of 221 stroke survivors aged <70 at stroke onset were in- cluded in the study. Spouses of independent stroke survivors ( n = 188) provided on average 0.15 hr/day of practical support and 0.48 hr/day of being available. Corresponding figures for spouses of dependent stroke survivors ( n = 33) were 5.00 regarding practical support and 9.51 regarding being available. The mean annual cost of informal support provided for independent stroke survivors was estimated at €991 and €25,127 for dependent stroke survivor. Conclusion: The opportunity cost of informal support provided to dependent midlife stroke survivors is of a major magnitude many years after stroke onset and should be considered in economic evaluations of health care.
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38. |
- Persson, Josefine, 1981, et al.
(author)
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Long-term QALY-weights among spouses of dependent and independent midlife stroke survivors.
- 2017
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In: Quality of Life Research. - : Springer Science and Business Media LLC. - 0962-9343 .- 1573-2649. ; 26:11, s. 3059-3068
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Journal article (peer-reviewed)abstract
- PURPOSE: The aim of this study was to investigate whether the dependency of midlife stroke survivors had any long-term impact on their spouses' QALY-weights. METHOD: Data on stroke survivors, controls, and spouses were collected from the 7-year follow-up of the Sahlgrenska Academy Study on Ischemic Stroke. Health-related quality of life was assessed by the SF-36, and the preference-based health state values were assessed with the SF-6D. Spouses of dependent and independent stroke survivors were categorized according to their scores on the modified Rankin Scale. An ordinary least squares regression analysis was used to evaluate whether the dependency of the stroke survivors had any impact on the spouses' QALY-weights. RESULT: Cohabitant dyads of 247 stroke survivors aged <70 at stroke onset and 245 dyads of controls were included in the study. Spouses of dependent stroke survivors (n = 50) reported a significant lower mean QALY-weight of 0.69 in comparison to spouses of independent stroke survivors (n = 197) and spouses of controls, (n = 245) who both reported a mean QALY-weight of 0.77. The results from the regression analysis showed that higher age of the spouse and dependency of the stroke survivor had a negative association with the spouses' QALY-weights. CONCLUSION: The QALY-weights for spouses of dependent midlife stroke survivors were significantly reduced compared to spouses of independent midlife stroke survivors. This indicates that the inclusion of spouses' QALYs in evaluations of early treatment and rehabilitation efforts to reduce stroke patients' dependency would capture more of the total effect in dyads of stroke survivors.
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39. |
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40. |
- Persson, Josefine, 1981, et al.
(author)
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Stroke survivors’ long-term QALY-weights in relation to their spouses’ QALY-weights and informal support: a cross-sectional study
- 2017
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In: Health and Quality of Life Outcomes. - : Springer Science and Business Media LLC. - 1477-7525. ; 15
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Journal article (peer-reviewed)abstract
- Background: Healthcare interventions that have positive effects on the stroke survivors’ health-related quality of Life (HRQoL) and quality-adjusted life-years (QALYs) might also have positive effects for their spouses in terms of improved HRQoL and/or reduced spousal informal support. However, knowle dge about stroke survivors ’ HRQoL and QALY and the consequences for their spouses’ HRQoL and QALY is limited. Therefore, the aim of this study was to describe the HRQoL and QALY-weights in dyads of stroke survivors in comparison with dyads of healthy controls, and to study the relationship between the stroke survivors’ QALY-weights and consequences for spouses in terms of QALY-weight and annual cost of informal support, using a long-term perspective. Methods: Data on stroke survivors, controls, and spouses were collected from the seven-year follow-up of the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). HRQoL was assessed by the SF-36, and the preference-based health state values were assessed with the SF-6D. The magnitude of the support was assessed with a study specific time-diary. An ordinary least squares (OLS) regression was used to estimate the association between stroke survivors’ and spouses’ QALY-weights. A two-part econometri c model was used to estimate the association between stroke survivors’ QALY-weights and the time spent and cost of spouses’ informal support. Results: Cohabitant dyads of 248 stroke survivors’ aged <70 at stroke onset and 245 controls were included in the study. Stroke survivors had lower HRQoL in the SF-36 domains physical functioning, physical role, general health, vitality (P <0.001), and social functioning (P = 0.005) in comparison with their cohabitant spouses. There was no significant difference in HRQoL for the dyads of controls. The results from the regression analyses showed that lo wer QALY-weights of the stroke survivors were associated with lower QALY-weights of their spouses and increased annual cost of spousal informal support. Conclusion: Our results show that the QALY-weight s for stroke surv ivors had consequences for their spouses in terms of annual cost of spousal informal support and QALY-weights. Hence, economic evalu ation of interventions that improve the HRQoL of the stroke survivors but ignore the consequences for their spouses may underestimate the value of the intervention.
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41. |
- Pfeiffer, D., et al.
(author)
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Genetic Imbalance Is Associated With Functional Outcome After Ischemic Stroke
- 2019
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In: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 50:2, s. 298-304
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Journal article (peer-reviewed)abstract
- Background and Purpose-We sought to explore the effect of genetic imbalance on functional outcome after ischemic stroke (IS). Methods-Copy number variation was identified in high-density single-nucleotide polymorphism microarray data of IS patients from the CADISP (Cervical Artery Dissection and Ischemic Stroke Patients) and SiGN (Stroke Genetics Network)/ GISCOME (Genetics of Ischaemic Stroke Functional Outcome) networks. Genetic imbalance, defined as total number of protein-coding genes affected by copy number variations in an individual, was compared between patients with favorable (modified Rankin Scale score of 0-2) and unfavorable (modified Rankin Scale score of = 3) outcome after 3 months. Subgroup analyses were confined to patients with imbalance affecting ohnologs-a class of dose-sensitive genes, or to those with imbalance not affecting ohnologs. The association of imbalance with outcome was analyzed by logistic regression analysis, adjusted for age, sex, stroke subtype, stroke severity, and ancestry. Results-The study sample comprised 816 CADISP patients (age 44.2 +/- 10.3 years) and 2498 SiGN/GISCOME patients (age 67.7 +/- 14.2 years). Outcome was unfavorable in 122 CADISP and 889 SiGN/GISCOME patients. Multivariate logistic regression analysis revealed that increased genetic imbalance was associated with less favorable outcome in both samples (CADISP: P=0.0007; odds ratio=0.89; 95% CI, 0.82-0.95 and SiGN/GISCOME: P=0.0036; odds ratio=0.94; 95% CI, 0.91-0.98). The association was independent of age, sex, stroke severity on admission, stroke subtype, and ancestry. On subgroup analysis, imbalance affecting ohnologs was associated with outcome (CADISP: odds ratio=0.88; 95% CI, 0.80-0.95 and SiGN/GISCOME: odds ratio=0.93; 95% CI, 0.89-0.98) whereas imbalance without ohnologs lacked such an association. Conclusions-Increased genetic imbalance was associated with poorer functional outcome after IS in both study populations. Subgroup analysis revealed that this association was driven by presence of ohnologs in the respective copy number variations, suggesting a causal role of the deleterious effects of genetic imbalance.
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42. |
- Pulit, SL, et al.
(author)
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Loci associated with ischaemic stroke and its subtypes (SiGN): a genome-wide association study.
- 2016
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In: The Lancet. Neurology. - 1474-4465. ; 15:2, s. 174-84
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Journal article (peer-reviewed)abstract
- The discovery of disease-associated loci through genome-wide association studies (GWAS) is the leading genetic approach to the identification of novel biological pathways underlying diseases in humans. Until recently, GWAS in ischaemic stroke have been limited by small sample sizes and have yielded few loci associated with ischaemic stroke. We did a large-scale GWAS to identify additional susceptibility genes for stroke and its subtypes.To identify genetic loci associated with ischaemic stroke, we did a two-stage GWAS. In the first stage, we included 16851 cases with state-of-the-art phenotyping data and 32473 stroke-free controls. Cases were aged 16 to 104 years, recruited between 1989 and 2012, and subtypes of ischaemic stroke were recorded by centrally trained and certified investigators who used the web-based protocol, Causative Classification of Stroke (CCS). We constructed case-control strata by identifying samples that were genotyped on nearly identical arrays and were of similar genetic ancestral background. We cleaned and imputed data by use of dense imputation reference panels generated from whole-genome sequence data. We did genome-wide testing to identify stroke-associated loci within each stratum for each available phenotype, and we combined summary-level results using inverse variance-weighted fixed-effects meta-analysis. In the second stage, we did in-silico lookups of 1372 single nucleotide polymorphisms identified from the first stage GWAS in 20941 cases and 364736 unique stroke-free controls. The ischaemic stroke subtypes of these cases had previously been established with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system, in accordance with local standards. Results from the two stages were then jointly analysed in a final meta-analysis.We identified a novel locus (G allele at rs12122341) at 1p13.2 near TSPAN2 that was associated with large artery atherosclerosis-related stroke (first stage odds ratio [OR] 1·21, 95% CI 1·13-1·30, p=4·50×10(-8); joint OR 1·19, 1·12-1·26, p=1·30×10(-9)). Our results also supported robust associations with ischaemic stroke for four other loci that have been reported in previous studies, including PITX2 (first stage OR 1·39, 1·29-1·49, p=3·26×10(-19); joint OR 1·37, 1·30-1·45, p=2·79×10(-32)) and ZFHX3 (first stage OR 1·19, 1·11-1·27, p=2·93×10(-7); joint OR 1·17, 1·11-1·23, p=2·29×10(-10)) for cardioembolic stroke, and HDAC9 (first stage OR 1·29, 1·18-1·42, p=3·50×10(-8); joint OR 1·24, 1·15-1·33, p=4·52×10(-9)) for large artery atherosclerosis stroke. The 12q24 locus near ALDH2, which has previously been associated with all ischaemic stroke but not with any specific subtype, exceeded genome-wide significance in the meta-analysis of small artery stroke (first stage OR 1·20, 1·12-1·28, p=6·82×10(-8); joint OR 1·17, 1·11-1·23, p=2·92×10(-9)). Other loci associated with stroke in previous studies, including NINJ2, were not confirmed.Our results suggest that all ischaemic stroke-related loci previously implicated by GWAS are subtype specific. We identified a novel gene associated with large artery atherosclerosis stroke susceptibility. Follow-up studies will be necessary to establish whether the locus near TSPAN2 can be a target for a novel therapeutic approach to stroke prevention. In view of the subtype-specificity of the associations detected, the rich phenotyping data available in the Stroke Genetics Network (SiGN) are likely to be crucial for further genetic discoveries related to ischaemic stroke.US National Institute of Neurological Disorders and Stroke, National Institutes of Health.
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43. |
- Schirmer, M. D., et al.
(author)
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White matter hyperintensity quantification in large-scale clinical acute ischemic stroke cohorts - The MRI-GENIE study
- 2019
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In: Neuroimage-Clinical. - : Elsevier BV. - 2213-1582. ; 23
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Journal article (peer-reviewed)abstract
- White matter hyperintensity (WMH) burden is a critically important cerebrovascular phenotype linked to prediction of diagnosis and prognosis of diseases, such as acute ischemic stroke (AIS). However, current approaches to its quantification on clinical MRI often rely on time intensive manual delineation of the disease on T2 fluid attenuated inverse recovery (FLAIR), which hinders high-throughput analyses such as genetic discovery. In this work, we present a fully automated pipeline for quantification of WMH in clinical large-scale studies of AIS. The pipeline incorporates automated brain extraction, intensity normalization and WMH segmentation using spatial priors. We first propose a brain extraction algorithm based on a fully convolutional deep learning architecture, specifically designed for clinical FLAIR images. We demonstrate that our method for brain extraction outperforms two commonly used and publicly available methods on clinical quality images in a set of 144 subject scans across 12 acquisition centers, based on dice coefficient (median 0.95; inter-quartile range 0.94-0.95; p < 0.01) and Pearson correlation of total brain volume (r = 0.90). Subsequently, we apply it to the large-scale clinical multi-site MRI-GENIE study (N = 2783) and identify a decrease in total brain volume of -2.4 cc/year. Additionally, we show that the resulting total brain volumes can successfully be used for quality control of image preprocessing. Finally, we obtain WMH volumes by building on an existing automatic WMH segmentation algorithm that delineates and distinguishes between different cerebrovascular pathologies. The learning method mimics expert knowledge of the spatial distribution of the WMH burden using a convolutional auto-encoder. This enables successful computation of WMH volumes of 2533 clinical AIS patients. We utilize these results to demonstrate the increase of WMH burden with age (0.950 cc/year) and show that single site estimates can be biased by the number of subjects recruited.
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44. |
- Soderholm, M., et al.
(author)
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Genome-wide association meta-analysis of functional outcome after ischemic stroke
- 2019
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 92:12
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Journal article (peer-reviewed)abstract
- Objective To discover common genetic variants associated with poststroke outcomes using a genome-wide association (GWA) study. Methods The study comprised 6,165 patients with ischemic stroke from 12 studies in Europe, the United States, and Australia included in the GISCOME (Genetics of Ischaemic Stroke Functional Outcome) network. The primary outcome was modified Rankin Scale score after 60 to 190 days, evaluated as 2 dichotomous variables (0-2 vs 3-6 and 0-1 vs 2-6) and subsequently as an ordinal variable. GWA analyses were performed in each study independently and results were meta-analyzed. Analyses were adjusted for age, sex, stroke severity (baseline NIH Stroke Scale score), and ancestry. The significance level was p < 5 x 10(-8). Results We identified one genetic variant associated with functional outcome with genome-wide significance (modified Rankin Scale scores 0-2 vs 3-6, p = 5.3 x 10(-9)). This intronic variant (rs1842681) in the LOC105372028 gene is a previously reported trans-expression quantitative trait locus for PPP1R21, which encodes a regulatory subunit of protein phosphatase 1. This ubiquitous phosphatase is implicated in brain functions such as brain plasticity. Several variants detected in this study demonstrated suggestive association with outcome (p < 10(-5)), some of which are within or near genes with experimental evidence of influence on ischemic stroke volume and/or brain recovery (e.g., NTN4, TEK, and PTCH1). Conclusions In this large GWA study on functional outcome after ischemic stroke, we report one significant variant and several variants with suggestive association to outcome 3 months after stroke onset with plausible mechanistic links to poststroke recovery. Future replication studies and exploration of potential functional mechanisms for identified genetic variants are warranted.
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45. |
- Stanne, Tara M, 1979, et al.
(author)
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A Genome-wide Study of Common and Rare Genetic Variants Associated with Circulating Thrombin Activatable Fibrinolysis Inhibitor
- 2018
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In: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 118:2, s. 298-308
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Journal article (peer-reviewed)abstract
- Thrombin-activatable fibrinolysis inhibitor (TAFI) plays a central role in haemostasis, and plasma TAFI concentrations are heritable. Candidate gene studies have identified several variants within the gene encoding TAFI, CPB2, that explain part of the estimated heritability. Here, we describe an exploratory genome-wide association study to identify novel variants within and outside of the CPB2 locus that influence plasma concentrations of intact TAFI and/or the extent of TAFI activation (measured by released TAFI activation peptide, TAFI-AP) amongst 3,260 subjects from Southern Sweden. We also explored the role of rare variants on the HumanExome BeadChip. We confirmed the association with previously reported common variants in CPB2 for both intact TAFI and TAFI-AP, and discovered novel associations with variants in putative CPB2 enhancers. We identified a gene-based association with intact TAFI at CPB2 (PSKAT-O = 2.8 x 10(-8)), driven by two novel rare nonsynonymous single nucleotide polymorphisms (SNPs; I420N and D177G). Carriers of the rare variant of D177G (rs140446990; MAF 0.2%) had lower intact TAFI and TAFI-AP concentrations compared with non-carriers (intact TAFI, geometricmean 53 vs. 78%, PT-test < 5 x 10(-7); TAFI-AP 63 vs. 99%, P(T-tes)t = 7.2 x 10(-4)). For TAFI-AP, we identified a genome-wide significant association at an intergenic region of chromosome 3p14.1 and five gene-based associations (all PSKAT-O = 5 x 10(-6)). Using well-characterized assays together with a genome-wide association study and a rare-variant approach, we verified CPB2 to be the primary determinant of TAFI concentrations and identified putative secondary loci (candidate variants and genes) associated with intact TAFI and TAFI-AP that require independent validation.
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46. |
- Stanne, Tara M, 1979, et al.
(author)
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Low Circulating Acute Brain-Derived Neurotrophic Factor Levels Are Associated With Poor Long-Term Functional Outcome After Ischemic Stroke.
- 2016
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In: Stroke; a journal of cerebral circulation. - 1524-4628 .- 0039-2499. ; 47:7, s. 1943-1945
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Journal article (peer-reviewed)abstract
- Brain-derived neurotrophic factor (BDNF) plays important roles in brain plasticity and repair, and it influences stroke outcomes in animal models. Circulating BDNF concentrations are lowered in patients with traumatic brain injury, and low BDNF predicts poor recovery after this injury. We sought to investigate whether circulating concentrations of BDNF are altered in the acute phase of ischemic stroke and whether they are associated with short- or long-term functional outcome.
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47. |
- Söderholm, M, et al.
(author)
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Exome array analysis of ischaemic stroke : results from a southern Swedish study
- 2016
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In: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 23:12, s. 1722-1728
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Journal article (peer-reviewed)abstract
- BACKGROUND AND PURPOSE: Genome-wide association (GWA) studies have identified a few risk loci for ischaemic stroke, but these variants explain only a small part of the genetic contribution to the disease. Coding variants associated with amino acid substitutions or premature termination of protein synthesis could have a large effect on disease risk. We performed an exome array analysis for ischaemic stroke.METHODS: Patients with ischaemic stroke (n = 2385) and control subjects (n = 6077) from three Swedish studies were genotyped with the Illumina HumanOmniExpressExome BeadChip. Single-variant association analysis and gene-based tests were performed of exome variants with minor allele frequency of < 5%. A separate GWA analysis was also performed, based on 700 000 genotyped common markers and subsequent imputation.RESULTS: No exome variant or gene was significantly associated with all ischaemic stroke after Bonferroni correction (all P > 1.8 × 10(-6) for single-variant and >4.15 × 10(-6) for gene-based analysis). The strongest association in single-variant analysis was found for a missense variant in the DNAH11 gene (rs143362381; P = 5.01 × 10(-6) ). In gene-based tests, the strongest association was for the ZBTB20 gene (P = 7.9 × 10(-5) ). The GWA analysis showed that the sample was homogenous (median genomic inflation factor = 1.006). No genome-wide significant association with overall ischaemic stroke risk was found. However, previously reported associations for the PITX2 and ZFHX3 gene loci with cardioembolic stroke subtype were replicated (P = 7 × 10(-15) and 6 × 10(-3) ).CONCLUSIONS: This exome array analysis did not identify any single variants or genes reaching the pre-defined significance level for association with ischaemic stroke. Further studies on exome variants should be performed in even larger, well-defined and subtyped samples.
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48. |
- Traylor, Matthew, et al.
(author)
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Genetic Variation at 16q24.2 is associated with small vessel stroke.
- 2017
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In: Annals of neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 81:3, s. 383-394
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Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have been successful at identifying associations with stroke and stroke subtypes, but have not yet identified any associations solely with small vessel stroke (SVS). SVS comprises a quarter of all ischaemic stroke and is a major manifestation of cerebral small vessel disease, the primary cause of vascular cognitive impairment. Studies across neurological traits have shown younger onset cases have an increased genetic burden. We leveraged this increased genetic burden by performing an age-at-onset informed GWAS meta-analysis, including a large younger onset SVS population, to identify novel associations with stroke.We used a three-stage age-at-onset informed GWAS to identify novel genetic variants associated with stroke. On identifying a novel locus associated with SVS, we assessed its influence on other small vessel disease phenotypes, as well as on mRNA expression of nearby genes, and on DNA methylation of nearby CpG sites in whole blood and in the fetal brain.We identified an association with SVS in 4,203 cases and 50,728 controls on chromosome 16q24.2 (OR(95% CI)=1.16(1.10-1.22); p=3.2x10(-9) ). The lead SNP (rs12445022) was also associated with cerebral white matter hyperintensities (OR(95% CI)=1.10(1.05-1.16); p=5.3x10(-5) ; N=3,670), but not intracerebral haemorrhage (OR(95% CI)=0.97(0.84-1.12); p=0.71; 1,545 cases, 1,481 controls). rs12445022 is associated with mRNA expression of ZCCHC14 in arterial tissues (p=9.4x10(-7) ), and DNA methylation at probe cg16596957 in whole blood (p=5.3x10(-6) ).16q24.2 is associated with SVS. Associations of the locus with expression of ZCCHC14 and DNA methylation suggest the locus acts through changes to regulatory elements. This article is protected by copyright. All rights reserved.
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49. |
- Wu, O., et al.
(author)
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Big Data Approaches to Phenotyping Acute Ischemic Stroke Using Automated Lesion Segmentation of Multi-Center Magnetic Resonance Imaging Data
- 2019
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In: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 50:7, s. 1734-1741
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Journal article (peer-reviewed)abstract
- Background and Purpose- We evaluated deep learning algorithms' segmentation of acute ischemic lesions on heterogeneous multi-center clinical diffusion-weighted magnetic resonance imaging (MRI) data sets and explored the potential role of this tool for phenotyping acute ischemic stroke. Methods- Ischemic stroke data sets from the MRI-GENIE (MRI-Genetics Interface Exploration) repository consisting of 12 international genetic research centers were retrospectively analyzed using an automated deep learning segmentation algorithm consisting of an ensemble of 3-dimensional convolutional neural networks. Three ensembles were trained using data from the following: (1) 267 patients from an independent single-center cohort, (2) 267 patients from MRI-GENIE, and (3) mixture of (1) and (2). The algorithms' performances were compared against manual outlines from a separate 383 patient subset from MRI-GENIE. Univariable and multivariable logistic regression with respect to demographics, stroke subtypes, and vascular risk factors were performed to identify phenotypes associated with large acute diffusion-weighted MRI volumes and greater stroke severity in 2770 MRI-GENIE patients. Stroke topography was investigated. Results- The ensemble consisting of a mixture of MRI-GENIE and single-center convolutional neural networks performed best. Subset analysis comparing automated and manual lesion volumes in 383 patients found excellent correlation (rho=0.92; P<0.0001). Median (interquartile range) diffusion-weighted MRI lesion volumes from 2770 patients were 3.7 cm(3) (0.9-16.6 cm(3)). Patients with small artery occlusion stroke subtype had smaller lesion volumes (P<0.0001) and different topography compared with other stroke subtypes. Conclusions- Automated accurate clinical diffusion-weighted MRI lesion segmentation using deep learning algorithms trained with multi-center and diverse data is feasible. Both lesion volume and topography can provide insight into stroke subtypes with sufficient sample size from big heterogeneous multi-center clinical imaging phenotype data sets.
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50. |
- Åberg, Daniel, 1973, et al.
(author)
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Homeostasis model assessment of insulin resistance and outcome of ischemic stroke in non-diabetic patients - a prospective observational study
- 2019
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In: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 19:1
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Journal article (peer-reviewed)abstract
- BackgroundInsulin resistance (IR) in relation to diabetes is a risk factor for ischemic stroke (IS), whereas less is known about non-diabetic IR and outcome after IS.MethodsIn non-diabetic IS (n=441) and controls (n=560) from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), IR was investigated in relation to IS severity and functional outcome. IR was evaluated acutely and after 3months using the Homeostasis model assessment of IR (HOMA-IR). Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS). Functional outcome was evaluated using the modified Rankin Scale (mRS) after 3months, 2 and 7years. Associations were evaluated by logistic regression.ResultsHigher acute and 3-month HOMA-IR was observed in IS compared to the controls (both p<0.001) and in severe compared to mild IS (both p<0.05). High acute HOMA-IR was associated with poor outcome (mRS 3-6) after 3months and 7years [crude Odds ratios (ORs), 95% confidence intervals (CIs) 1.50, 1.07-2.11 and 1.59, 1.11-2.30, respectively], but not after 2years. These associations lost significance after adjustment for all covariates including initial stroke severity. In the largest IS subtype (cryptogenic stroke), acute HOMA-IR was associated with poor outcome after 2years also after adjustment for age and stroke severity (OR 2.86, 95% CI 1.01-8.12).ConclusionsIn non-diabetic IS patients, HOMA-IR was elevated and related to stroke severity, but after adjustment for IS severity, the associations between HOMR-IR and poor outcome lost significance. This could suggest that elevated IR mostly is a part of the acute IS morbidity. However, in the subgroup of cryptogenic stroke, the associations with poor outcome withstood correction for stroke severity.
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