Background: The longitudinal associations of sleep timing and time in bed (TIB) with dementia and cognitive decline in older adults are unclear.

Methods: This population-based cohort study used data from 1982 participants who were aged >= 60 years, free of dementia, and living in rural communities in western Shandong, China. At the baseline (2014) and follow-up (2018) examinations, sleep parameters were assessed using standard questionnaires. Cognitive function was measured using the Mini-Mental State Examination (MMSE). Dementia was diagnosed following the DSM-IV criteria, and the NIA-AA criteria for Alzheimer disease (AD). Data were analyzed using restricted cubic splines, Cox proportional-hazards models, and general linear models.

Results: During the mean follow-up of 3.7 years, dementia was diagnosed in 97 participants (68 with AD). Restricted cubic spline curves showed J-shaped associations of sleep duration, TIB, and rise time with dementia risk, and a reverse J-shaped association with mid-sleep time. When sleep parameters were categorized into tertiles, the multivariable-adjusted hazard ratio (HR) of incident dementia was 1.69 (95%CI 1.01-2.83) for baseline sleep duration >8 hours (vs. 7-8 h), 2.17 (1.22-3.87) for bedtime before 9 p.m. (vs. 10 p.m. or later), and 2.00 (1.23-3.24) for mid-sleep time before 1 a.m. (vs. 1-1.5 a.m.). Early bedtime and mid-sleep time were significantly associated with incident AD (HR range: 2.25-2.51; p < 0.05). Among individuals who were free of dementia at follow-up, baseline long TIB, early bedtime and mid-sleep time, early and late rise time, and prolonged TIB and advanced bedtime and mid-sleep time from baseline to follow-up were associated with a greater decline in MMSE score (p < 0.05). These associations with cognitive decline were statistically evident mainly among men or participants who were aged 60-74 years.

Conclusions: Long TIB and early sleep timing are associated with an increased risk of dementia, and the associations with greater cognitive decline are evident only among older people aged 60-74 years and men.

Background: Shorter leukocyte telomere length (LTL) is associated with aging and dementia. Impact of lifestyle changes on LTL, and relation to cognition and genetic susceptibility for dementia, has not been investigated in randomized controlled trials (RCTs).

Methods: Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability is a 2-year RCT enrolling 1260 participants at risk for dementia from the general population, aged 60-77 years, randomly assigned (1:1) to multidomain lifestyle intervention or control group. The primary outcome was cognitive change (Neuropsychological Test Battery z-score). Relative LTL was measured using quantitative real-time polymerase chain reaction (trial registration: NCT01041989).

Results: This exploratory LTL substudy included 756 participants (377 intervention, 379 control) with baseline and 24-month LTL measurements. The mean annual LTL change (SD) was -0.016 (0.19) in the intervention group and -0.023 (0.17) in the control group. Between-group difference was nonsignificant (unstandardized beta-coefficient 0.007, 95% CI -0.015 to 0.030). Interaction analyses indicated better LTL maintenance among apolipoprotein E (APOE)-epsilon 4 carriers versus noncarriers: 0.054 (95% CI 0.007 to 0.102); younger versus older participants: -0.005 (95% CI -0.010 to -0.001); and those with more versus less healthy lifestyle changes: 0.047 (95% CI 0.005 to 0.089). Cognitive intervention benefits were more pronounced among participants with better LTL maintenance for executive functioning (0.227, 95% CI 0.057 to 0.396) and long-term memory (0.257, 95% CI 0.024 to 0.489), with a similar trend for Neuropsychological Test Battery total score (0.127, 95% CI -0.011 to 0.264).

Conclusions: This is the first large RCT showing that a multidomain lifestyle intervention facilitated LTL maintenance among subgroups of older people at risk for dementia, including APOE-epsilon 4 carriers. LTL maintenance was associated with more pronounced cognitive intervention benefits.

Objectives: Perceived financial strain is associated with various health conditions, but it is unknown whether it is associated with an increased risk for dementia. The goal is to examine the associations between midlife perceptions of financial situation and dementia risk later in life.

Methods: Participants were derived from the Cardiovascular Risk Factors, Aging, and Dementia population-based cohort study (n = 2000) (between 1972 and 1987, baseline mean age 50 years) in Finland. Participants returned for two re-examinations in late life (in 1998 and 2005–2008, mean age 71 and 78 years). In this study, 1442 subjects that participated in at least one re-examination (mean total follow-up 25 years) were included in analyses. Financial strain was measured using two questions in midlife on perceptions of financial situation and perceptions of changes in financial situation. For each question, participants were categorized into three groups reporting improvement, worsening, or stability, with the latter set as the reference group. Analyses were adjusted for potential confounding factors.

Results: The group reporting better financial situation had a reduced risk for dementia (fully adjusted model: odds ratio (OR): 0.53, 95% confidence interval (CI): 0.33–0.86). In contrast, the group reporting worse financial situation did not have an increased risk for dementia (OR: 1.04, 95% CI: 0.53–2.02). Analyses on perceptions of current financial situation showed that the groups reporting satisfaction or dissatisfaction with financial situation did not differ in risk for dementia.

Conclusion: This study is the first to show that midlife improvements in financial situation are associated with a reduced dementia risk later in life. Potential pathways related to stress reduction, improved lifestyle, and potential biological mechanisms are discussed.

Objective: To investigate the associations between sleep disturbances in mid-life and late-life and late-life cognitive status. Methods: In four population-based studies (three Swedish studies: H70 study, Kungsholmen Project (KP) and The Swedish Panel Study of Living Conditions of the Oldest Old (SWEOLD); and one Finnish study: Cardiovascular Risk Factors, Aging and Dementia (CAIDE)), participants provided self-reports on insomnia, nightmares and general sleep problems. Late-life cognitive status was measured by the Mini Mental State Exam (MMSE). The associations between late-life sleep disturbances and cognition 3-11 years later were investigated across all studies (n = 3210). Mean baseline ages were 70 (CAIDE, H70 and SWEOLD), and 84 years (KP). Additional analyses examined the association between midlife sleep and late-life cognition using CAIDE (21 and 31 years follow-up, n = 1306, mean age 50 years), and SWEOLD (20-24 years follow-up, n = 2068, mean age 58 years). Ordered logistic regressions, adjusted for potential baseline confounders, were used in the analyses. Results: Late-life sleep disturbances were associated with poorer cognition after 3-11 years (fully adjusted beta = -0.12, 95% CI = -0.24 to -0.01). Midlife nightmares and insomnia were also associated with lower MMSE scores (fully adjusted beta = -0.28, 95% CI = -0.49 to -0.07 and beta = -0.20, 95% CI = -0.39 to -0.01), although the latter association was attenuated after adjusting for lifestyle/health-related confounders. Midlife general sleep problems were not associated with late-life MMSE performance. Conclusions: Sleep disturbances and midlife nightmares were associated with lower MMSE scores, which suggests that sleep disturbances in earlier life stages can be associated with worse late-life cognition.