Sleep dysregulation is a feature of dementia but it remains unclear whether sleep duration prior to old age is associated with dementia incidence. Using data from 7959 participants of the Whitehall ...II study, we examined the association between sleep duration and incidence of dementia (521 diagnosed cases) using a 25-year follow-up. Here we report higher dementia risk associated with a sleep duration of six hours or less at age 50 and 60, compared with a normal (7 h) sleep duration, although this was imprecisely estimated for sleep duration at age 70 (hazard ratios (HR) 1.22 (95% confidence interval 1.01-1.48), 1.37 (1.10-1.72), and 1.24 (0.98-1.57), respectively). Persistent short sleep duration at age 50, 60, and 70 compared to persistent normal sleep duration was also associated with a 30% increased dementia risk independently of sociodemographic, behavioural, cardiometabolic, and mental health factors. These findings suggest that short sleep duration in midlife is associated with an increased risk of late-onset dementia.
We examined whether obesity at ages 50, 60, and 70 years is associated with subsequent dementia. Changes in body mass index (BMI) for more than 28 years before dementia diagnosis were compared with ...changes in BMI in those free of dementia.
A total of 10,308 adults (33% women) aged 35 to 55 years in 1985 were followed up until 2015. BMI was assessed six times and 329 cases of dementia were recorded.
Obesity (BMI ≥30 kg/m2) at age 50 years (hazard ratio = 1.93; 1.35–2.75) but not at 60 or 70 years was associated with risk of dementia. Trajectories of BMI differed in those with dementia compared with all others (P < .0001) or to matched control subjects (P < .0001) such that BMI in dementia cases was higher from 28 years (P = .001) to 16 years (P = .05) and lower starting 8 years before diagnosis.
Obesity in midlife and weight loss in the preclinical phase characterizes dementia; the current obesity epidemic may affect future dementia rates.
Objectives
To determine whether fast gait speed at study baseline and change in gait speed had independent associations with disability onset.
Design
Cohort study with 11‐year follow‐up (1999–2010).
...Setting
Three‐City Study center, Dijon, France.
Participants
Community‐dwelling individuals aged 65 to 85 (N = 3,814, 61% female).
Measurements
Fast gait speed (over 6 m) was assessed up to five times and disability (mobility (Rosow‐Breslau scale), instrumental activities of daily living (IADLs; Lawton‐Brody scale), basic activities of daily living (ADLs; Katz scale)) six times. A hierarchical disability indicator was constructed; participants were considered disabled if they reported difficulties with mobility and IADLs or with mobility, IADLs, and ADLs. The association between baseline fast gait speed and its slope of change and disability incidence was examined using joint models for longitudinal and time‐to‐event data.
Results
Over follow‐up, 628 participants (68% women) developed disability. Mean fast gait speed at baseline was 1.54 m/s, and annual decline was 0.017 m/s. The hazard ratio of disability per standard deviation (SD) (−0.22 m/s) slower baseline fast gait speed was 1.77 (95% confidence interval (CI) = 1.60–1.94) and for one‐SD (−0.013 m/s) faster annual decline was 1.38 (95% CI = 1.10–1.73) when both parameters were included in a sex‐ and age‐adjusted model. All associations remained statistically significant in multivariable models, except for slope of change when chronic conditions were added to the model; of chronic conditions, dyspnea was the main contributor.
Conclusion
Accelerated decline in fast gait speed was associated with disability independent of baseline fast gait speed. These results confirm the importance of measuring gait speed repeatedly in elderly adults to identify those at higher risk of disability and the need to identify determinants of decline, because they are likely to be targets for prevention and treatment to reduce disability risk.
Sleep duration has been shown to be associated with individual chronic diseases but its association with multimorbidity, common in older adults, remains poorly understood. We examined whether sleep ...duration is associated with incidence of a first chronic disease, subsequent multimorbidity and mortality using data spanning 25 years.
Data were drawn from the prospective Whitehall II cohort study, established in 1985 on 10,308 persons employed in the London offices of the British civil service. Self-reported sleep duration was measured 6 times between 1985 and 2016, and data on sleep duration was extracted at age 50 (mean age (standard deviation) = 50.6 (2.6)), 60 (60.3 (2.2)), and 70 (69.2 (1.9)). Incidence of multimorbidity was defined as having 2 or more of 13 chronic diseases, follow-up up to March 2019. Cox regression, separate analyses at each age, was used to examine associations of sleep duration at age 50, 60, and 70 with incident multimorbidity. Multistate models were used to examine the association of sleep duration at age 50 with onset of a first chronic disease, progression to incident multimorbidity, and death. Analyses were adjusted for sociodemographic, behavioral, and health-related factors. A total of 7,864 (32.5% women) participants free of multimorbidity had data on sleep duration at age 50; 544 (6.9%) reported sleeping ≤5 hours, 2,562 (32.6%) 6 hours, 3,589 (45.6%) 7 hours, 1,092 (13.9%) 8 hours, and 77 (1.0%) ≥9 hours. Compared to 7-hour sleep, sleep duration ≤5 hours was associated with higher multimorbidity risk (hazard ratio: 1.30, 95% confidence interval = 1.12 to 1.50; p < 0.001). This was also the case for short sleep duration at age 60 (1.32, 1.13 to 1.55; p < 0.001) and 70 (1.40, 1.16 to 1.68; p < 0.001). Sleep duration ≥9 hours at age 60 (1.54, 1.15 to 2.06; p = 0.003) and 70 (1.51, 1.10 to 2.08; p = 0.01) but not 50 (1.39, 0.98 to 1.96; p = 0.07) was associated with incident multimorbidity. Among 7,217 participants free of chronic disease at age 50 (mean follow-up = 25.2 years), 4,446 developed a first chronic disease, 2,297 progressed to multimorbidity, and 787 subsequently died. Compared to 7-hour sleep, sleeping ≤5 hours at age 50 was associated with an increased risk of a first chronic disease (1.20, 1.06 to 1.35; p = 0.003) and, among those who developed a first disease, with subsequent multimorbidity (1.21, 1.03 to 1.42; p = 0.02). Sleep duration ≥9 hours was not associated with these transitions. No association was found between sleep duration and mortality among those with existing chronic diseases. The study limitations include the small number of cases in the long sleep category, not allowing conclusions to be drawn for this category, the self-reported nature of sleep data, the potential for reverse causality that could arise from undiagnosed conditions at sleep measures, and the small proportion of non-white participants, limiting generalization of findings.
In this study, we observed short sleep duration to be associated with risk of chronic disease and subsequent multimorbidity but not with progression to death. There was no robust evidence of an increased risk of chronic disease among those with long sleep duration at age 50. Our findings suggest an association between short sleep duration and multimorbidity.
Studies of diet and depression have focused primarily on individual nutrients.
To examine the association between dietary patterns and depression using an overall diet approach.
Analyses were carried ...on data from 3486 participants (26.2% women, mean age 55.6 years) from the Whitehall II prospective cohort, in which two dietary patterns were identified: 'whole food' (heavily loaded by vegetables, fruits and fish) and 'processed food' (heavily loaded by sweetened desserts, fried food, processed meat, refined grains and high-fat dairy products). Self-reported depression was assessed 5 years later using the Center for Epidemiologic Studies - Depression (CES-D) scale.
After adjusting for potential confounders, participants in the highest tertile of the whole food pattern had lower odds of CES-D depression (OR = 0.74, 95% CI 0.56-0.99) than those in the lowest tertile. In contrast, high consumption of processed food was associated with an increased odds of CES-D depression (OR = 1.58, 95% CI 1.11-2.23).
In middle-aged participants, a processed food dietary pattern is a risk factor for CES-D depression 5 years later, whereas a whole food pattern is protective.
The concept of brain maintenance refers to the preservation of brain integrity in older age, while cognitive reserve refers to the capacity to maintain cognition in the presence of neurodegeneration ...or aging‐related brain changes. While both mechanisms are thought to contribute to individual differences in cognitive function among older adults, there is currently no “gold standard” for measuring these constructs. Using machine‐learning methods, we estimated brain and cognitive age based on deviations from normative aging patterns in the Whitehall II MRI substudy cohort (N = 537, age range = 60.34–82.76), and tested the degree of correspondence between these constructs, as well as their associations with premorbid IQ, education, and lifestyle trajectories. In line with established literature highlighting IQ as a proxy for cognitive reserve, higher premorbid IQ was linked to lower cognitive age independent of brain age. No strong evidence was found for associations between brain or cognitive age and lifestyle trajectories from midlife to late life based on latent class growth analyses. However, post hoc analyses revealed a relationship between cumulative lifestyle measures and brain age independent of cognitive age. In conclusion, we present a novel approach to characterizing brain and cognitive maintenance in aging, which may be useful for future studies seeking to identify factors that contribute to brain preservation and cognitive reserve mechanisms in older age.
Using machine learning, we estimated brain and cognitive age based on deviations from normative aging patterns in the Whitehall II MRI substudy cohort, and tested the degree of correspondence between these constructs, as well as their associations with premorbid IQ, education, and lifestyle trajectories. The study presents a novel approach to characterizing brain and cognitive maintenance in aging, which may be useful for future studies seeking to identify factors that contribute to brain preservation and cognitive reserve in older age.
Socioeconomic disadvantage is a risk factor for many diseases. We characterised cascades of these conditions by using a data-driven approach to examine the association between socioeconomic status ...and temporal sequences in the development of 56 common diseases and health conditions.
In this multi-cohort study, we used data from two Finnish prospective cohort studies: the Health and Social Support study and the Finnish Public Sector study. Our pooled prospective primary analysis data comprised 109 246 Finnish adults aged 17–77 years at study entry. We captured socioeconomic status using area deprivation and education at baseline (1998–2013). Participants were followed up for health conditions diagnosed according to the WHO International Classification of Diseases until 2016 using linkage to national health records. We tested the generalisability of our findings with an independent UK cohort study—the Whitehall II study (9838 people, baseline in 1997, follow-up to 2017)—using a further socioeconomic status indicator, occupational position.
During 1 110 831 person-years at risk, we recorded 245 573 hospitalisations in the Finnish cohorts; the corresponding numbers in the UK study were 60 946 hospitalisations in 186 572 person-years. Across the three socioeconomic position indicators and after adjustment for lifestyle factors, compared with more advantaged groups, low socioeconomic status was associated with increased risk for 18 (32·1%) of the 56 conditions. 16 diseases formed a cascade of inter-related health conditions with a hazard ratio greater than 5. This sequence began with psychiatric disorders, substance abuse, and self-harm, which were associated with later liver and renal diseases, ischaemic heart disease, cerebral infarction, chronic obstructive bronchitis, lung cancer, and dementia.
Our findings highlight the importance of mental health and behavioural problems in setting in motion the development of a range of socioeconomically patterned physical illnesses. Policy and health-care practice addressing psychological health issues in social context and early in the life course could be effective strategies for reducing health inequalities.
UK Medical Research Council, US National Institute on Aging, NordForsk, British Heart Foundation, Academy of Finland, and Helsinki Institute of Life Science.
Social inequalities in mortality persist in high-income countries with universal health care, and the mechanisms by which these inequalities are generated remain unclear. We aimed to examine whether ...social inequalities were present before or after the onset of adverse health conditions (multimorbidity, frailty, and disability).
Our analysis was based on data from the ongoing Whitehall II cohort study, which enrolled British civil servants aged 35–55 years in 1985–88. Participants were assessed for three indicators of socioeconomic status (education, occupational position, and literacy) at age 50 years. Participants underwent clinical examinations (in 2002–04, 2007–09, 2012–13, and 2015–16) for assessment of frailty (two or more of low physical activity, slow walking speed, poor grip strength, weight loss, and exhaustion) and disability (two or more difficulties in bathing, dressing, going to the toilet, transferring, feeding, and walking). In addition, electronic health records were used to assess the incidence of multimorbidity (two or more of diabetes, coronary heart disease, stroke, chronic obstructive pulmonary disease, depression, arthritis, cancer, dementia, and Parkinson's disease) and mortality. In analyses adjusted for sociodemographic factors, we used multistate models to examine social inequalities in transitions from healthy state to adverse health conditions and subsequently to mortality.
Of 10 308 individuals in the Whitehall II study cohort, 6425 had relevant data available at 50 years and to the end of follow-up on Aug 31, 2017, and were included in our analysis. Participants were followed up for a median of 23·6 years (IQR 19·6–28·9). 1694 (26·4%) of 6425 participants developed multimorbidity, 1733 (27·0%) became frail, 692 (10·8%) had a disability, and 611 (9·5%) died. Multimorbidity (hazard ratio HR 4·12 95% CI 3·41–4·98), frailty (HR 2·38 95% CI 1·93–2·93), and disability (HR 1·73 95% CI 1·34–2·22) were associated with increased risk of mortality; these associations were not modified by socioeconomic status. In multistate models, occupation was the socioeconomic status indicator that was most strongly associated with inequalities in the transition from healthy state to multimorbidity (HR 1·54 95% CI 1·37–1·73), to frailty (HR 2·08 95% CI 1·85–2·33), and to disability (HR 1·44 95% CI 1·18–1·74). Socioeconomic status indicators did not affect transitions to mortality in those with multimorbidity, frailty, or disability.
Socioeconomic status affects the risk of multimorbidity, frailty, and disability, but does not affect the risk of mortality after the onset of these adverse health conditions. Therefore, primary prevention is key to reducing social inequalities in mortality. Of the three adverse health conditions, multimorbidity had the strongest association with mortality, making it a central target for improving population health.
UK Medical Research Council; National Institute on Aging, National Institutes of Health; British Heart Foundation.
Summary Background Governments need to increase the proportion of the population in work in most developed countries because of ageing populations. We investigated longitudinally how self-perceived ...health is affected by work and retirement in older workers. Methods We examined trajectories of self-rated health in 14 714 employees (11 581 79% men) from the French national gas and electricity company, the GAZEL cohort, for up to 7 years before and 7 years after retirement, with yearly measurements from 1989 to 2007. We analysed data by use of repeated-measures logistic regression with generalised estimating equations. Findings Overall, suboptimum health increased with age. However, between the year before retirement and the year after, the estimated prevalence of suboptimum health fell from 19·2% (95% CI 18·5–19·9) to 14·3% (13·7–14·9), corresponding to a gain in health of 8–10 years. We noted this retirement-related improvement in men (odds ratio 0·68, 95% CI 0·64–0·73) and women (0·74, 0·67–0·83), and across occupational grades (low 0·72, 0·63–0·82; high 0·70, 0·63–0·77), and it was maintained throughout the 7 years after retirement. A poor work environment and health complaints before retirement were associated with a steeper yearly increase in the prevalence of suboptimum health while still in work, and a greater retirement-related improvement; however, people with a combination of high occupational grade, low demands, and high satisfaction at work showed no such retirement-related improvement. Interpretation These findings suggest that the burden of ill-health, in terms of perceived health problems, is substantially relieved by retirement for all groups of workers apart from those with ideal working conditions, and that working life for older workers needs to be redesigned to achieve higher labour-market participation. Funding Swedish Council for Working Life and Social Research, Academy of Finland, INSERM (France), BUPA Foundation (UK), European Science Foundation, and Economic and Social Research Council (UK).
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