| 1. |
- Pedersen, Nancy L., et al.
(författare)
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IGEMS : The Consortium on Interplay of Genes and Environment Across Multiple Studies - An Update
- 2019
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Ingår i: Twin Research and Human Genetics. - : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 22:6, s. 809-816
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Tidskriftsartikel (refereegranskat)abstract
- The Interplay of Genes and Environment across Multiple Studies (IGEMS) is a consortium of 18 twin studies from 5 different countries (Sweden, Denmark, Finland, United States, and Australia) established to explore the nature of gene-environment (GE) interplay in functioning across the adult lifespan. Fifteen of the studies are longitudinal, with follow-up as long as 59 years after baseline. The combined data from over 76,000 participants aged 14-103 at intake (including over 10,000 monozygotic and over 17,000 dizygotic twin pairs) support two primary research emphases: (1) investigation of models of GE interplay of early life adversity, and social factors at micro and macro environmental levels and with diverse outcomes, including mortality, physical functioning and psychological functioning; and (2) improved understanding of risk and protective factors for dementia by incorporating unmeasured and measured genetic factors with a wide range of exposures measured in young adulthood, midlife and later life.
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| 2. |
- Beam, Christopher R., et al.
(författare)
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Estimating Likelihood of Dementia in the Absence of Diagnostic Data : A Latent Dementia Index in 10 Genetically Informed Studies
- 2022
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 90:3, s. 1187-1201
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Epidemiological research on dementia is hampered by differences across studies in how dementia is classified, especially where clinical diagnoses of dementia may not be available. OBJECTIVE: We apply structural equation modeling to estimate dementia likelihood across heterogeneous samples within a multi-study consortium and use the twin design of the sample to validate the results. METHODS: Using 10 twin studies, we implement a latent variable approach that aligns different tests available in each study to assess cognitive, memory, and functional ability. The model separates general cognitive ability from components indicative of dementia. We examine the validity of this continuous latent dementia index (LDI). We then identify cut-off points along the LDI distributions in each study and align them across studies to distinguish individuals with and without probable dementia. Finally, we validate the LDI by determining its heritability and estimating genetic and environmental correlations between the LDI and clinically diagnosed dementia where available. RESULTS: Results indicate that coordinated estimation of LDI across 10 studies has validity against clinically diagnosed dementia. The LDI can be fit to heterogeneous sets of memory, other cognitive, and functional ability variables to extract a score reflective of likelihood of dementia that can be interpreted similarly across studies despite diverse study designs and sampling characteristics. Finally, the same genetic sources of variance strongly contribute to both the LDI and clinical diagnosis. CONCLUSION: This latent dementia indicator approach may serve as a model for other research consortia confronted with similar data integration challenges.
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| 3. |
- Dahl, Anna, 1975-, et al.
(författare)
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Being overweight in midlife is associated with lower cognitive ability and steeper cognitive decline in late life
- 2010
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Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences. - : Oxford University Press. - 1079-5006 .- 1758-535X. ; 65A:1, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although an increasing body of evidence links being overweight in midlife with an increased risk for dementia in late life, no studies have examined the association between being overweight in midlife and cognitive ability in late life. Our aim was to examine the association between being overweight in midlife as measured by body mass index (BMI) and cognitive ability assessed over time. METHODS: Participants in the Swedish Adoption/Twin Study Aging were derived from a population-based sample. The participants completed baseline surveys in 1963 or 1973 (mean age 41.6 years, range 25-63 years). The surveys included questions about height, weight, diseases, and lifestyle factors. Beginning in 1986, the same individuals were assessed on neuropsychological tests every 3 years (except in 1995) until 2002. During the study period, 781 individuals who were 50 years and older (60% women) had at least one complete neuropsychological assessment. A composite score of general cognitive ability was derived from the cognitive test battery for each measurement occasion. RESULTS: Latent growth curve models adjusted for twinness showed that persons with higher midlife BMI scores had significantly lower general cognitive ability and significantly steeper longitudinal decline than their thinner counterparts. The association did not change substantially when persons who developed dementia during the study period were excluded from the analysis. CONCLUSIONS: Higher midlife BMI scores precede lower general cognitive ability and steeper cognitive decline in both men and women. The association does not seem to be mediated by an increased risk for dementia
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| 4. |
- Ericsson, Malin, et al.
(författare)
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Childhood social class and cognitive aging in the Swedish Adoption/Twin Study of Aging
- 2017
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 114:27, s. 7001-7006
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Tidskriftsartikel (refereegranskat)abstract
- In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and parental social class based on the Swedish socioeconomic index. Cognitive ability included a general factor and the four domains of verbal, fluid, memory, and perceptual speed. Latent growth curve models of the longitudinal data tested whether level and change in cognitive performance differed as a function of childhood social class. Between-within twin-pair analyses were performed on twins reared apart to assess familial confounding. Childhood social class was significantly associated with mean-level cognitive performance at age 65 y, but not with rate of cognitive change. The association decreased in magnitude but remained significant after adjustments for level of education and the degree to which the rearing family was supportive toward education. A between-pair effect of childhood social class was significant in all cognitive domains, whereas within-pair estimates were attenuated, indicating genetic confounding. Thus, childhood social class is important for cognitive performance in adulthood on a population level, but the association is largely attributable to genetic influences.
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| 5. |
- Ernsth Bravell, Marie, et al.
(författare)
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Motor functioning differentially predicts mortality in men and women
- 2017
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Ingår i: Archives of gerontology and geriatrics (Print). - : Elsevier. - 0167-4943 .- 1872-6976. ; 72, s. 6-11
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionResearch indicates gender differences in functional performance at advanced ages, but little is known about their impact on longevity for men and women.ObjectiveTo derive a set of motor function factors from a battery of functional performance measures and examine their associations with mortality, incorporating possible gender interactions.MethodAnalyses were performed on the longitudinal Swedish Adoption/Twin Study of Aging (SATSA) including twenty-four assessments of motor function up to six times over a 19-year period. Three motor factors were derived from several factor analyses; fine motor, balance/upper strength, and flexibility. A latent growth curve model was used to capture longitudinal age changes in the motor factors and generated estimates of intercept at age 70 (I), rates of change before (S1) and after age 70 (S2) for each factor. Cox regression models were used to determine how gender in interaction with the motor factors was related to mortality.ResultsFemales demonstrated lower functional performance in all motor functions relative to men. Cox regression survival analyses demonstrated that both balance/upper strength, and fine motor function were significantly related to mortality. Gender specific analyses revealed that this was true for women only. For men, none of the motor factors were related to mortality.ConclusionWomen demonstrated more difficulties in all functioning facets, and only among women were motor functioning (balance/upper strength and fine motor function) associated with mortality. These results provide evidence for the importance of considering motor functioning, and foremost observed gender differences when planning for individualized treatment and rehabilitation.
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| 6. |
- Hallgren, Jenny, 1978-, et al.
(författare)
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Cognitive trajectories in relation to hospitalization among older Swedish adults
- 2018
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Ingår i: Archives of gerontology and geriatrics (Print). - : Elsevier. - 0167-4943 .- 1872-6976. ; 74, s. 9-14
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionResearch indicate that cognitive impairment might be related to hospitalization, but little is known about these effects over time.ObjectiveTo assess cognitive change before and after hospitalization among older adults in a population-based longitudinal study with up to 25 years of follow-up.MethodA longitudinal study on 828 community living men and women aged 50–86 from the Swedish Adoption/Twin Study of Ageing (SATSA) were linked to The Swedish National Inpatient Register. Up to 8 assessments of cognitive performance (general cognitive ability, verbal, spatial/fluid, memory, and processing speed) from 1986 to 2010 were available. Latent growth curve modelling was used to assess the association between cognitive performance and hospitalization including spline models to analyse cognitive trajectories pre- and post-hospitalization.ResultsA total of 735 persons (89%) had at least one hospital admission during the follow-up. Mean age at first hospitalization was 70.2 (±9.3) years. Persons who were hospitalized exhibited a lower mean level of cognitive performance in general ability, processing speed and spatial/fluid ability compared with those who were not hospitalized. The two-slope models revealed steeper cognitive decline before hospitalization than after among those with at least one hospitalization event, as compared to non-hospitalized persons who showed steeper cognitive decline after the centering age of 70 years.ConclusionsPersons being hospitalized in late life have lower cognitive performance across all assessed domains. The results indicate that the main decline occurs before the hospitalization, and not after. This might indicate that when you get treatment you also benefit cognitively.
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| 7. |
- Hallgren, Jenny, 1978-, et al.
(författare)
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Factors associated with hospitalization risk among community living middle aged and older persons : Results from the Swedish Adoption/Twin Study of Aging (SATSA)
- 2016
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Ingår i: Archives of gerontology and geriatrics (Print). - : Elsevier. - 0167-4943 .- 1872-6976. ; 66, s. 102-108
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Tidskriftsartikel (refereegranskat)abstract
- The aims of the present study were to: (1) describe and compare individual characteristics of hospitalized and not hospitalized community living persons, and (2) to determine factors that are associated with hospitalization risk over time. We conducted a prospective study with a multifactorial approach based on the population-based longitudinal Swedish Adoption/Twin Study of Aging (SATSA). A total of 772 Swedes (mean age at baseline 69.7 years, range 46–103, 59.8% females) answered a postal questionnaire about physical and psychological health, personality and socioeconomic factors. During nine years of follow-up, information on hospitalizations and associated diagnoses were obtained from national registers. Results show that 484 persons (63%) had at least one hospital admission during the follow-up period. The most common causes of admission were cardiovascular diseases (25%) and tumors (22%). Cox proportional hazard regression models controlling for age, sex and dependency within twin pairs, showed that higher age (HR = 1.02, p < 0.001) and more support from relatives (HR = 1.09, p = 0.028) were associated with increased risk of hospitalization, while marital status (unmarried (HR = 0.75, p = 0.033) and widow/widower (HR = 0.69, p < 0.001)) and support from friends (HR = 0.93, p = 0.029) were associated with lower risk of hospitalization. Social factors were important for hospitalization risk even when medical factors were controlled for in the analyses. Number of diseases was not a risk in the final regression model. Hospitalization risk was also different for women and men and within different age groups. We believe that these results might be used in future interventions targeting health care utilization.
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| 8. |
- Karlsson, Ida K., et al.
(författare)
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Adiposity and the risk of dementia : mediating effects from inflammation and lipid levels
- 2022
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Ingår i: European Journal of Epidemiology. - : Springer Nature Switzerland AG.. - 0393-2990 .- 1573-7284. ; 37:12, s. 1261-1271
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Tidskriftsartikel (refereegranskat)abstract
- While midlife adiposity is a risk factor for dementia, adiposity in late-life appears to be associated with lower risk. What drives the associations is poorly understood, especially the inverse association in late-life. Using results from genome-wide association studies, we identified inflammation and lipid metabolism as biological pathways involved in both adiposity and dementia. To test if these factors mediate the effect of midlife and/or late-life adiposity on dementia, we then used cohort data from the Swedish Twin Registry, with measures of adiposity and potential mediators taken in midlife (age 40–64, n = 5999) or late-life (age 65–90, n = 7257). Associations between body-mass index (BMI), waist-hip ratio (WHR), C-reactive protein (CRP), lipid levels, and dementia were tested in survival and mediation analyses. Age was used as the underlying time scale, and sex and education included as covariates in all models. Fasting status was included as a covariate in models of lipids. One standard deviation (SD) higher WHR in midlife was associated with 25% (95% CI 2–52%) higher dementia risk, with slight attenuation when adjusting for BMI. No evidence of mediation through CRP or lipid levels was present. After age 65, one SD higher BMI, but not WHR, was associated with 8% (95% CI 1–14%) lower dementia risk. The association was partly mediated by higher CRP, and suppressed when high-density lipoprotein levels were low. In conclusion, the negative effects of midlife adiposity on dementia risk were driven directly by factors associated with body fat distribution, with no evidence of mediation through inflammation or lipid levels. There was an inverse association between late-life adiposity and dementia risk, especially where the body’s inflammatory response and lipid homeostasis is intact.
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| 9. |
- Karlsson, Ida K., et al.
(författare)
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Age-dependent effects of body mass index across the adult life span on the risk of dementia : A cohort study with a genetic approach
- 2020
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Ingår i: BMC Medicine. - : BioMed Central. - 1741-7015. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: While a high body mass index (BMI) in midlife is associated with higher risk of dementia, high BMI in late-life may be associated with lower risk. This study combined genetic designs with longitudinal data to achieve a better understanding of this paradox. Methods: We used longitudinal data from 22,156 individuals in the Swedish Twin Registry (STR) and 25,698 from the Health and Retirement Study (HRS). The STR sample had information about BMI from early adulthood through late-life, and the HRS sample from age 50 through late-life. Survival analysis was applied to investigate age-specific associations between BMI and dementia risk. To examine if the associations are influenced by genetic susceptibility to higher BMI, an interaction between BMI and a polygenic score for BMI (PGSBMI) was included in the models and results stratified into those with genetic predisposition to low, medium, and higher BMI. In the STR, co-twin control models were applied to adjust for familial factors beyond those captured by the PGSBMI. Results: At age 35-49, 5 units higher BMI was associated with 15% (95% CI 7-24%) higher risk of dementia in the STR. There was a significant interaction (p = 0.04) between BMI and the PGSBMI, and the association present only among those with genetic predisposition to low BMI (HR 1.38, 95% CI 1.08-1.78). Co-twin control analyses indicated genetic influences. After age 80, 5 units higher BMI was associated with 10-11% lower risk of dementia in both samples. There was a significant interaction between late-life BMI and the PGSBMI in the STR (p = 0.01), but not the HRS, with the inverse association present only among those with a high PGSBMI (HR 0.70, 95% CI 0.52-0.94). No genetic influences were evident from co-twin control models of late-life BMI. Conclusions: Not only does the association between BMI and dementia differ depending on age at BMI measurement, but also the effect of genetic influences. In STR, the associations were only present among those with a BMI in opposite direction of their genetic predisposition, indicating that the association between BMI and dementia across the life course might be driven by environmental factors and hence likely modifiable. © 2020 The Author(s).
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| 10. |
- Karlsson, Ida K., et al.
(författare)
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Change in cognition and body mass index in relation to preclinical dementia
- 2021
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Ingår i: Alzheimer’s & Dementia. - : John Wiley & Sons. - 2352-8737. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: To study if declining cognition drives weight loss in preclinical dementia, we examined the longitudinal association between body mass index (BMI) and cognitive abilities in individuals who did or did not later develop dementia.Methods: Using data from individuals spanning age 50 to 89, we applied dual change score models separately in individuals who remained cognitively intact (n = 1498) and those who were diagnosed with dementia within 5 years of last assessment (n = 459).Results: Among the cognitively intact, there was a bidirectional association: Stable BMI predicted stable cognition and vice versa. Among individuals who were subsequently diagnosed with dementia, the association was unidirectional: Higher BMI predicted declining cognition but cognition did not predict change in BMI.Discussion: Although BMI and cognition stabilized each other when cognitive functioning was intact, this buffering effect was missing in the preclinical dementia phase. This finding indicates that weight loss in preclinical dementia is not driven by declining cognition.
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