| 1. |
- Hoevenaar-Blom, Marieke P., et al.
(författare)
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Improving data sharing in research with context-free encoded missing data
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- Lack of attention to missing data in research may result in biased results, loss of power and reduced generalizability. Registering reasons for missing values at the time of data collection, or-in the case of sharing existing data-before making data available to other teams, can save time and efforts, improve scientific value and help to prevent erroneous assumptions and biased results. To ensure that encoding of missing data is sufficient to understand the reason why data are missing, it should ideally be context-free. Therefore, 11 context-free codes of missing data were carefully designed based on three completed randomized controlled clinical trials and tested in a new randomized controlled clinical trial by an international team consisting of clinical researchers and epidemiologists with extended experience in designing and conducting trials and an Information System expert. These codes can be divided into missing due to participant and/or participation characteristics (n = 6), missing by design (n = 4), and due to a procedural error (n = 1). Broad implementation of context-free missing data encoding may enhance the possibilities of data sharing and pooling, thus allowing more powerful analyses using existing data.
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| 2. |
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| 3. |
- Norgren, Jakob, et al.
(författare)
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Capillary blood tests may overestimate ketosis : triangulation between three different measures of beta-hydroxybutyrate
- 2020
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Ingår i: American Journal of Physiology. Endocrinology and Metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 318:2, s. e184-E188
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Tidskriftsartikel (refereegranskat)abstract
- The ketone body beta-hydroxybutyrate (BHB), assessed by a point-of-care meter in venous whole blood (BHBv), was used as the main outcome in a study on nutritional ketosis in healthy older adults. Two other BHB measures were also used in the study for validation and exploratory purposes, and here we report findings on correlation and agreement between those three methods. Ketosis in the range of 0-1.5 mmol/L was induced in 15 healthy volunteers by intake of medium-chain fatty acids after a 12-h fast. BHBv was assessed at 12 time points for 4 h. The same point-of-care meter was also used to test capillary blood (BHBc) at three time points, and a laboratory test determined total ketones (TK) in plasma (BHBp + acetoacetate) at four time points. A total of 180 cases included simultaneous data on BHBv, BHBc, BHBp, and TK. TK correlated with BHBp (Pearson's r = 0.99), BHBv (r = 0.91), and BHBc (r = 0.91), all P < 0.0001. BHBv and BHBp had good agreement in absolute values. However, the slope between BHBc and BHBv, measured with the same device, was in the range of 0.64-0.78 in different regression models, indicating substantially higher BHB concentrations in capillary versus venous blood. We conclude that all three methods are valid to detect relative changes in ketosis, but our results highlight the importance of method considerations and the possible need to adjust cutoffs, e.g., in the management of ketoacidosis and in the evaluation and comparison of dietary interventions.
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| 4. |
- Ballin, Marcel, et al.
(författare)
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Time-varying risk of death after SARS-CoV-2 infection in Swedish long-term care facility residents: a matched cohort study
- 2022
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:11
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate whether SARS-CoV-2 infection in residents of long-term care (LTC) facilities is associated with higher mortality after the acute phase of infection, and to estimate survival in uninfected residents.DESIGN: Extended follow-up of a previous, propensity score-matched, retrospective cohort study based on the Swedish Senior Alert register.SETTING: LTC facilities in Sweden.PARTICIPANTS: n=3604 LTC residents with documented SARS-CoV-2 until 15 September 2020 matched to 3604 uninfected controls using time-dependent propensity scores on age, sex, health status, comorbidities, prescription medications, geographical region and Senior Alert registration time. In a secondary analysis (n=3731 in each group), geographical region and Senior Alert registration time were not matched for in order to increase the follow-up time in controls and allow for an estimation of median survival.PRIMARY OUTCOME MEASURES: All-cause mortality until 24 October 2020, tracked using the National Cause of Death Register.RESULTS: Median age was 87 years and 65% were women. Excess mortality peaked at 5 days after documented SARS-CoV-2-infection (HR 21.5, 95% CI 15.9 to 29.2), after which excess mortality decreased. From the second month onwards, mortality rate became lower in infected residents than controls. The HR for death during days 61-210 of follow-up was 0.76 (95% CI 0.62 to 0.93). The median survival of uninfected controls was 1.6 years, which was much lower than the national life expectancy in Sweden at age 87 (5.05 years in men, 6.07 years in women).CONCLUSIONS: The risk of death after SARS-CoV-2 infection in LTC residents peaked after 5 days and decreased after 2 months, probably because the frailest residents died during the acute phase, leaving healthier residents remaining. The limited life expectancy in this population suggests that LTC resident status should be accounted for when estimating years of life lost due to COVID-19.
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| 5. |
- Enache, Daniela, et al.
(författare)
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CAIDE Dementia Risk Score and biomarkers of neurodegeneration in memory clinic patients without dementia
- 2016
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 42, s. 124-131
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to explore cross-sectional associations between Cardiovascular Risk Factors, Aging and Dementia Study (CAIDE) Dementia Risk Score and dementia-related cerebrospinal fluid and neuroimaging biomarkers in 724 patients without dementia from the Memory Clinic at Karolinska University Hospital, Huddinge, Sweden. We additionally evaluated the score's capacity to predict dementia. Two risk score versions were calculated: one including age, gender, obesity, hyperlipidemia, and hypertension; and one additionally including apolipoprotein E (APOE) ε4 carrier status. Cerebrospinal fluid was analyzed for amyloid β (Aβ), total tau, and phosphorylated tau. Visual assessments of medial temporal lobe atrophy (MTA), global cortical atrophy-frontal subscale, and Fazekas scale for white matter changes (WMC) were performed. Higher CAIDE Dementia Risk Score (version without APOE) was significantly associated with higher total tau, more severe MTA, WMC, and global cortical atrophy-frontal subscale. Higher CAIDE Dementia Risk Score (version with APOE) was associated with reduced Aβ, more severe MTA, and WMC. CAIDE Dementia Risk Score version with APOE seemed to predict dementia better in this memory clinic population with short follow-up than the version without APOE.
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| 6. |
- Exalto, Lieza G, et al.
(författare)
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Midlife risk score for the prediction of dementia four decades later
- 2013
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Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 10:5, s. 562-570
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe objective of this study was to obtain external validation of the only available midlife dementia risk score cardiovascular risk factors , aging and dementia study (CAIDE) constituting age, education, hypertension, obesity, and hyperlipidemia in a larger, more diverse population. Our second aim was to improve the CAIDE risk score by additional midlife risk factors.MethodsThis retrospective cohort study was conducted in an integrated health care delivery system. A total of 9480 Kaiser Permanente members who participated in a health survey study (age range, 40–55 years) from 1964 to 1973 were included in this study. Dementia diagnoses from primary care and medical specialist visits were collected from January 1, 1994 to January 16, 2006, using International Classification of Diseases 9 codes 290.0, 290.1 for “possible dementia,” and 331.0 and 290.4 for “specialist confirmed dementia.” Risk model prediction and validation were examined with the C statistic, net reclassification improvement, and integrated discrimination improvement. Dementia risk per sum score was calculated with Kaplan-Meier estimates.ResultsA total of 2767 participants (25%) were diagnosed with any type of dementia, of which 1011 diagnoses (10.7%) were specialist-confirmed diagnoses. Average time between midlife examination and end of follow-up was 36.1 years. The CAIDE risk score replicated well with a C statistic of 0.75, quite similar to the original CAIDE C statistic of 0.78. The CAIDE score also predicted well within different race strata. Other midlife risk factors (central obesity, depressed mood, diabetes mellitus, head trauma, lung function, and smoking) did not improve predictability. The risk score allowed stratification of participants into those with 40-year low (9%) and high (29%) dementia risk.ConclusionsA combination of modifiable vascular risk factors in midlife is highly predictive of the likelihood of dementia decades later. Possible dementia prevention strategies should point to a life course perspective on maintaining vascular health.
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| 7. |
- Hagg, Sara, et al.
(författare)
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Age, Frailty, and Comorbidity as Prognostic Factors for Short-Term Outcomes in Patients With Coronavirus Disease 2019 in Geriatric Care
- 2020
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Ingår i: Journal of the American Medical Directors Association. - : ELSEVIER SCIENCE INC. - 1525-8610 .- 1538-9375. ; 21:11, s. 1555-1559
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To analyze whether frailty and comorbidities are associated with in-hospital mortality and discharge to home in older adults hospitalized for coronavirus disease 2019 (COVID-19). Design: Single-center observational study. Setting and Participants: Patients admitted to geriatric care in a large hospital in Sweden between March 1 and June 11, 2020; 250 were treated for COVID-19 and 717 for other diagnoses. Methods: COVID-19 diagnosis was clinically confirmed by positive reverse transcription polymerase chain reaction test or, if negative, by other methods. Patient data were extracted from electronic medical records, which included Clinical Frailty Scale (CFS), and were further used for assessments of the Hospital Frailty Risk Score (HFRS) and the Charlson Comorbidity Index (CCI). In-hospital mortality and home discharge were followed up for up to 25 and 28 days, respectively. Multivariate Cox regression models adjusted for age and sex were used. Results: Among the patients with COVID-19, in-hospital mortality rate was 24% and home discharge rate was 44%. Higher age was associated with in-hospital mortality (hazard ratio [HR] 1.05 per each year, 95% confidence interval [CI] 1.01.1.08) and lower probability of home discharge (HR 0.97, 95% CI 0.95.0.99). CFS (>5) and CCI, but not HFRS, were predictive of in-hospital mortality (HR 1.93, 95% CI 1.02.3.65 and HR 1.27, 95% CI 1.02.1.58, respectively). Patients with CFS >5 had a lower probability of being discharged home (HR 0.38, 95% CI 0.25.0.58). CCI and HFRS were not associated with home discharge. In general, effects were more pronounced in men. Acute kidney injury was associated with in-hospital mortality and hypertension with discharge to home. Other comorbidities (diabetes, cardiovascular disease, lung diseases, chronic kidney disease and dementia) were not associated with either outcome. Conclusions and Implications: Of all geriatric patients with COVID-19, 3 out of 4 survived during the study period. Our results indicate that in addition to age, the level of frailty is a useful predictor of short-term COVID-19 outcomes in geriatric patients. (C) 2020 AMDA - The Society for Post-Acute and Long-Term Care Medicine.
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| 8. |
- Hartikainen, Päivi, et al.
(författare)
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Cortical thickness in frontotemporal dementia, mild cognitive impairment, and Alzheimer's disease
- 2012
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 30:4, s. 857-874
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Tidskriftsartikel (refereegranskat)abstract
- Cortical thickness analysis has been proposed as a potential diagnostic measure in memory disorders. In this retrospective study, we compared the cortical thickness values of 24 patients with frontotemporal dementia (FTD) to those of 25 healthy controls, 45 symptomatic subjects with stable mild cognitive impairment (S-MCI), 15 subjects with progressive mild cognitive impairment (P-MCI), and 36 patients with Alzheimer's disease (AD). The patterns of regions of thinning in FTD when compared to controls and also S-MCI patients showed similar trends; thinning of the bilateral frontal poles and bilateral medial temporal lobe structures, especially the anterior part of the gingulum, the uncus, and parahippocampal gyri. Cortical thinning in FTD was also found on the boundary regions of parietal and occipital lobes. In the P-MCI group compared to FTD, the trend of thinning in small distinct areas of the parietal and occipital lobes was observed. The FTD and AD groups did not differ statistically, but we found trends toward thinning in FTD of the left cingulate gyrus, and the left occipitotemporal gyri, and in AD of the inferior parietal, occipitoparietal, and the pericalcarine regions, more in the right hemisphere. In FTD, increased slowness in the executive test (Trail-Making A) correlated with the thinner cortex, whereas the language tests showed the lower scores, the thinner cortex in the left hemisphere. Cortical thickness might be a tool for detecting subtle changes in brain atrophy in screening of dementia prior to the development of diffuse or lobar atrophies.
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| 9. |
- Holleman, Jasper, et al.
(författare)
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Life-course stress, cognition, and diurnal cortisol in memory clinic patients without dementia
- 2024
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Ingår i: Archives of gerontology and geriatrics (Print). - : Elsevier. - 0167-4943 .- 1872-6976. ; 119
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To examine associations of life-course stress with cognition and diurnal cortisol patterns in older adulthood, as well as potential mediation effects of diurnal cortisol patterns and perceived stress on the association between life-course stress and cognition.METHODS: 127 participants without dementia were selected from a cohort of Swedish memory clinic patients. Cross-sectional associations between scores on two chronic stress questionnaires (perceived stress, stressful life events (SLEs)), five cognitive domains (overall cognition, memory, working memory, processing speed, perceptual reasoning), and two measures of diurnal cortisol patterns (total daily output, diurnal cortisol slope), as well as potential mediation effects of diurnal cortisol patterns and perceived stress on associations between life-course stress and cognition, were assessed using linear regressions.RESULTS: Greater lifetime exposure to SLEs was associated with worse memory, working memory, and processing speed performance, but not with diurnal cortisol patterns. A greater number of SLEs in late childhood was associated with worse working memory and processing speed, while a greater number of SLEs in non-recent adulthood were associated with better overall cognition and perceptual reasoning. Greater perceived stress was associated with a flattened diurnal cortisol slope, but not with cognition. No evidence for interplay between self-reported and physiological stress markers was found in relation to cognition, although there appeared to be a significant positive indirect association between economic/legal SLEs and the diurnal cortisol slope via perceived stress.CONCLUSIONS: The associations between SLEs and cognition depend on the period during which SLEs occur, but seem independent of late-life cortisol dysregulation.
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| 10. |
- Hooshmand, Babak, et al.
(författare)
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Association of Methionine to Homocysteine Status With Brain Magnetic Resonance Imaging Measures and Risk of Dementia
- 2019
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 76:11, s. 1198-1205
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Impairment of methylation status (ie, methionine to homocysteine ratio) may be a modifiable risk factor for structural brain changes and incident dementia.OBJECTIVE To investigate the association of serum markers of methylation status and sulfur amino acids with risk of incident dementia, Alzheimer disease (AD), and the rate of total brain tissue volume loss during 6 years.DESIGN, SETTING, AND PARTICIPANTS This population-based longitudinal study was performed from March 21, 2001, to October 10, 2010, in a sample of 2570 individuals aged 60 to 102 years from the Swedish Study on Aging and Care in Kungsholmen who were dementia free at baseline and underwent comprehensive examinations and structural brain magnetic resonance imaging (MRI) on 2 to 3 occasions during 6 years. Data analysis was performed from March 1, 2018, to October 1, 2018.MAIN OUTCOMES AND MEASURES Incident dementia, AD, and the rate of total brain volume loss.RESULTS This study included 2570 individuals (mean [SD] age, 73.1 [10.4] years; 1331 [56.5%] female). The methionine to homocysteine ratio was higher in individuals who consumed vitamin supplements (median, 1.9; interquartile range [IQR], 1.5-2.6) compared with those who did not (median, 1.8; IQR, 1.3-2.3; P<.001) and increased per each quartile increase of vitamin B-12 or folate. In the multiadjusted model, an elevated baseline serum total homocysteine level was associated with an increased risk of dementia and AD during 6 years: for the highest homocysteine quartile compared with the lowest, the hazard ratios (HRs) were 1.60 (95% CI, 1.01-2.55) for dementia and 2.33 (95% CI, 1.26-4.30) for AD. In contrast, elevated concentrations of methionine were associated with a decreased risk of dementia (HR, 0.54; 95% CI, 0.36-0.81) for the highest quartile compared with the lowest. Higher values of the methionine to homocysteine ratio were significantly associated with lower risk of dementia and AD: for the fourth methionine-homocysteine quartile compared with the first quartile, the HR was 0.44 (95% CI, 0.27-0.71) for incident dementia and 0.43 (95% CI, 0.23-0.80) for AD. In the multiadjusted linear mixed models, a higher methionine to homocysteine ratio was associated with a decreased rate of total brain tissue volume loss during the study period (beta [SE] per 1-SD increase, 0.038 [0.014]; P=.007).CONCLUSIONS AND RELEVANCE The methionine to homocysteine status was associated with dementia development and structural brain changes during the 6-year study period, suggesting that a higher methionine to homocysteine ratio may be important in reducing the rate of brain atrophy and decreasing the risk of dementia in older adults.
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