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Subjective health ratings are associated with dementia risk such that those who rate their health more poorly have increased risk for dementia. The genetic and environmental mechanisms underlying this association are unclear, as prior research cannot rule out whether the association is due to genetic confounds. The current study addresses this gap in two samples of twins, one from Sweden (N = 548) and one from Denmark (N = 4,373). Using genetically-informed, bivariate regression models, we assessed whether additive genetic effects explained the association between subjective health and dementia risk as indexed by a latent variable proxy measure. Age at intake, sex, education, depressive symptomatology, and follow-up time between subjective health and dementia risk assessments were included as covariates. Results indicate that genetic variance and other sources of confounding accounted for the majority of the effect of subjective health ratings on dementia risk. After adjusting for genetic confounding and other covariates, a small correlation was observed between subjective health and latent dementia risk in the Danish sample (r E  = - .09, p < .05). The results provide further support for the genetic association between subjective health and dementia risk, and also suggest that subjective ratings of health measures may be useful for predicting dementia risk., (© 2024. The Author(s).)

As the spread of COVID-19 has led to global efforts to social distance, concerns about the negative psychological effects of social isolation and loneliness have grown. The purpose of this commentary is to draw attention to 2 populations across the life span at risk for the psychological sequelae of social isolation and loneliness: young adults and old-old adults. We present data from three population-based longitudinal studies from two nations (United States and Sweden) to support this view. We then provide recommendations for the prevention of loneliness during social distancing as well as after social distancing measures are eased through implementation of programs that match young adults with older adults to foster intergenerational connection and group-based psychotherapy. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The Louisville Twin Study (LTS) began in 1958 and became a premier longitudinal twin study of cognitive development. The LTS continuously collected data from twins through 2000 after which the study closed indefinitely due to lack of funding. Now that the majority of the sample is age 40 or older (61.36%, N = 1770), the LTS childhood data can be linked to midlife cognitive functioning, among other physical, biological, social, and psychiatric outcomes. We report results from two pilot studies in anticipation of beginning the midlife phase of the LTS. The first pilot study was a participant tracking study, in which we showed that approximately 90% of the Louisville families randomly sampled (N = 203) for the study could be found. The second pilot study consisted of 40 in-person interviews in which twins completed cognitive, memory, biometric, and functional ability measures. The main purpose of the second study was to correlate midlife measures of cognitive functioning to a measure of biological age, which is an alternative index to chronological age that quantifies age as a function of the breakdown of structural and functional physiological systems, and then to relate both of these measures to twins' cognitive developmental trajectories. Midlife IQ was uncorrelated with biological age (- .01) while better scores on episodic memory more strongly correlated with lower biological age (- .19 to - .31). As expected, midlife IQ positively correlated with IQ measures collected throughout childhood and adolescence. Additionally, positive linear rates of change in FSIQ scores in childhood significantly correlated with biological age (- .68), physical functioning (.71), and functional ability (- .55), suggesting that cognitive development predicts lower biological age, better physical functioning, and better functional ability. In sum, the Louisville twins can be relocated to investigate whether and how early and midlife cognitive and physical health factors contribute to cognitive aging.

Objectives: This article examines whether sexual minority men and women experience greater increases in depressive symptoms and loneliness with age compared to heterosexual men and women., Methods: Using three waves of data from sexual minority (n Men  = 87 and n Women  = 62) and heterosexual (n Men  = 1,297 and n Women  = 1,362) older adults in the National Social Life, Health, and Aging Project, we used latent growth curve modeling to test whether change in depressive symptoms and loneliness varies across sexual orientation and whether annual household income and family support accounted for this change., Results: Although differences in the growth trajectories of depressive symptoms and loneliness across sexual orientation were not observed, gender differences were. Annual household income and family support more strongly influenced initial depressive symptoms and loneliness in sexual minority men and women than in heterosexual men and women., Conclusions: Trajectories of depressive symptoms and loneliness in older adulthood do not vary by sexual orientation. Economic and family resources may allow sexual minorities to cope effectively with depressive symptoms and loneliness., Clinical Implications: Clinicians should be cautious about assuming that older sexual minority group members are more susceptible to depressive symptoms and loneliness than heterosexual groups by virtue of their sexual preference.

Openness to experience has been found to be a correlate of successful aging outcomes yet also has been found to decline from middle age onward. We hypothesized that decline in openness would be associated with death. Using longitudinal data from the Swedish Adoption/Twin Study of Aging (SATSA), the analytic sample encompassed 1954 individuals, approximately two-thirds of whom were deceased. We tested whether openness declines across late adulthood and, central to our hypothesis, whether the decline correlated with age at death. Multivariate modeling adjusted for age at study entry, sex, education, as well as the time-varying effects of physical illness, depressive symptoms, and cognitive ability. Correlations between change in neuroticism and extraversion and death were modeled for comparison. A follow-up cotwin control analysis adjusted for genetic and environmental familial confounders. Significant mean-level change was identified in all personality traits, but only for openness was change correlated with age at death, in support of our hypothesis. The findings were not explained by health factors or cognition. Cotwin control analyses indicated that the twin who died earlier showed a greater drop in openness prior to death, compared with their cotwin measured at the same time points. There was no cotwin finding for neuroticism or extraversion. We suggest that declines in openness may reflect a change in goal orientation due to the experience of a shortened time horizon, leading to an optimized selection of experiences as people approach the end of life. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Risk for Alzheimer's disease (AD) is affected by multiple factors, including aging, obesity, and low testosterone. We previously showed that obesity and low testosterone independently and interactively exacerbate AD-related outcomes in young adult rodents. The goals of the present study are two-fold: to examine whether the effects of an obesogenic diet differ with increasing age and to determine if testosterone treatment in middle-aged and aged animals mitigates negative effects of the diet. Male brown Norway rats were maintained on control or high-fat diets for 12 weeks beginning in young adulthood, middle age, or advanced age. Separate cohorts of middle-aged and aged animals were treated with testosterone during dietary manipulations. Endpoints included metabolic indices, inflammation, cognitive performance, and neural health outcomes. Aging was associated with poorer outcomes that were generally exacerbated by high-fat diet, especially at middle age. Testosterone treatment was largely without benefit, exerting only subtle effects on a select number of measures. Understanding how the deleterious effects of obesity are affected by advancing age and the ability of protective strategies such as testosterone to reduce these effects may provide significant insight into both the development and prevention of age-related cognitive decline and AD., (Copyright © 2018 Elsevier Inc. All rights reserved.)

BackgroundEpidemiological research on dementia is hampered by differences across studies in how dementia is classified, especially where clinical diagnoses of dementia may not be available.ObjectiveWe 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.MethodsUsing 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.ResultsResults 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.ConclusionThis latent dementia indicator approach may serve as a model for other research consortia confronted with similar data integration challenges.

Objectives Loneliness may influence aging biomarkers related to cognitive functioning, for example, through accelerated DNA methylation (DNAm) aging. Methods In the present study, we tested whether six common DNAm age acceleration measures mediated the effects of baseline loneliness and five different longitudinal loneliness trajectories on general cognitive ability, immediate memory recall, delayed memory recall, and processing speed in 1,814 older adults in the Health and Retirement Study. Results We found that baseline loneliness and individuals who belong to the highest loneliness trajectories had poorer general cognitive ability and memory scores. Only DNAm age acceleration measures that index physiological comorbidities, unhealthy lifestyle factors (e.g. smoking), and mortality risk-mediated effects of baseline loneliness on general cognitive ability and memory functioning but not processing speed. These same DNAm measures mediated effects of the moderate-but-declining loneliness trajectory on cognitive functioning. Additionally, immediate and delayed memory scores were mediated by GrimAge Accel in the lowest and two highest loneliness trajectory groups. Total and mediated effects of loneliness on cognitive functioning outcomes were mainly accounted for by demographic, social, psychological, and physiological covariates, most notably self-rated health, depressive symptomatology, objective social isolation, and body mass index. Discussion Current findings suggest that DNAm biomarkers of aging, particularly GrimAge Accel, have promise for explaining the prospective association between loneliness and cognitive functioning outcomes. [ABSTRACT FROM AUTHOR]

Although several studies have shown small longitudinal associations between baseline loneliness and subsequent dementia risk, studies rarely test whether change in loneliness predicts dementia risk. Furthermore, as both increase with advancing age, genetic and environmental selection processes may confound the putative causal association between loneliness and dementia risk. We used a sample of 2,476 individual twins from three longitudinal twin studies of aging in the Swedish Twin Registry to test the hypothesis that greater positive change in loneliness predicts greater dementia risk. We then used a sample of 1,632 pairs of twins to evaluate the hypothesis that effects of change in loneliness on dementia risk would remain after adjusting for effects of genetic and environmental variance. Phenotypic model results suggest that mild levels of baseline loneliness predict greater dementia risk. Contrary to our hypothesis, change in loneliness did not correlate with dementia risk, regardless of whether genetic and environmental selection confounds were taken into account. Worsening loneliness with age may not confer greater dementia risk. [ABSTRACT FROM AUTHOR]

Objectives Education and cognition are closely associated, yet the role of spousal education is not well understood. We estimate the independent effects of own and spousal education on cognitive ability in late-life in Mexico, a developing country experiencing rapid aging. Method We analyzed 4,017 married dyads (age 50+) from the 2012 Mexican Health and Aging Study. Cognitive ability for married adults was a factor score from a single factor model. Using seemingly unrelated regression, we test whether spousal education influences older adults' cognitive ability, whether associations are explained by couple-level socioeconomic position, health and health behaviors, and social support, and whether associations differed by gender. Results Education and cognitive ability were correlated within couples. Higher spousal education was associated with better cognitive ability. Associations between spousal education and cognitive ability were independent of own education, did not differ by gender, and remained significant even after adjustment for couple-level socioeconomic position, health and health behaviors, and perceived social support. Discussion In addition to own education, spousal education was associated with better cognitive ability, even at relatively low levels of education. We discuss the possibility that spousal education may improve cognition via transmission of knowledge and mutually reinforcing cognitively stimulating environments. [ABSTRACT FROM AUTHOR]

It is well documented that memory is heritable and that older adults tend to have poorer memory performance than younger adults. However, whether the magnitudes of genetic and environmental contributions to late-life verbal episodic memory ability differ from those at earlier ages remains unresolved. Twins from 12 studies participating in the Interplay of Genes and Environment in Multiple Studies (IGEMS) consortium constituted the analytic sample. Verbal episodic memory was assessed with immediate word list recall (N = 35,204 individuals; 21,792 twin pairs) and prose recall (N = 3805 individuals; 2028 twin pairs), with scores harmonized across studies. Average test performance was lower in successively older age groups for both measures. Twin models found significant age moderation for both measures, with total inter-individual variance increasing significantly with age, although it was not possible definitively to attribute the increase specifically to either genetic or environmental sources. Pooled results across all 12 studies were compared to results where we successively dropped each study (leave-one-out) to assure results were not due to an outlier. We conclude the models indicated an overall increase in variance for verbal episodic memory that was driven by a combination of increases in the genetic and nonshared environmental parameters that were not independently statistically significant. In contrast to reported results for other cognitive domains, differences in environmental exposures are comparatively important for verbal episodic memory, especially word list learning. • Verbal episodic memory performance is poorer at older ages compared to midlife. • Individual variance in verbal episodic memory shows an increase across age. • Environmental variance unique to individuals is more important than genetic variance. • Genetic variance is greater for remembering a prose passage than a list of words. [ABSTRACT FROM AUTHOR]