Stability of metabolically healthy obesity over 8 years: the English Longitudinal Study of Ageing.

Objective Metabolically healthy obesity possibly reflects a transitional stage before the onset of metabolic dysfunction, but few studies have characterised this transition. We examined the behavioural and biological characteristics of healthy obese adults that progressed to an unhealthy state over 8 years follow-up. Methods Participants were 2422 men and women (aged 63.3±7.7 years, 44.2% men) from the English Longitudinal Study of Ageing. Obesity was defined as BMI ≥30 kg/m2. Based on blood pressure (BP), HDL-cholesterol, triglycerides, HbA1c and C-reactive protein (CRP) participants were classified as ‘healthy’ (0 or 1 metabolic abnormality) or ‘unhealthy’ (≥2 metabolic abnormalities). Results Over 8 years follow-up, 44.5% of healthy obese subjects had transitioned into an unhealthy state, compared to only 16.6 and 26.2% of healthy normal-weight and overweight adults respectively. Compared with healthy obese adults who remained stable, those who progressed to an unhealthy state were more likely to have high BP (75.0% vs 37.0%, age- and sex-adjusted odds ratio (OR) 8.9, 95% CI 4.7–17.0), high CRP (53.7% vs 17.0%, OR=8.6, 95% CI 4.1–18.0), high HbA1c (46.3% vs 5.9%, OR=13.8, 95% CI 6.1–31.2) and high triglycerides (45.4% vs 11.9%, OR=5.9, 95% CI 2.9–12.0) at follow-up, with excess risk remaining independent of lifestyle factors including self-reported physical activity. Progression to an unhealthy state was also linked with significant gains in waist circumference (B=2.7, 95% CI, 0.5–4.9 cm). Conclusion These data show that a healthy obesity phenotype is relatively unstable. Transition to an unhealthy state is characterised by multiple biological changes that are not fully explained by lifestyle risk factors

Contribution of smoking towards the association between socioeconomic position and dementia : 32-year follow-up of the Whitehall II prospective cohort study

Background There is consistent evidence of social inequalities in dementia but the mechanisms underlying this association remain unclear. We examined the role of smoking in midlife in socioeconomic differences in dementia at older ages.Methods Analyses were based on 9951 (67% men) participants, median age 44.3 [IQR=39.6, 50.3] years at baseline in 1985-1988, from the Whitehall II cohort study. Socioeconomic position (SEP) and smoking (smoking status (cur-rent, ex-, never-smoker), pack years of smoking, and smoking history score (combining status and pack-years)) were measured at baseline. Counterfactual mediation analysis was used to examine the contribution of smoking to the association between SEP and dementia.Findings During a median follow-up of 31.6 (IQR 31.1, 32.6) years, 628 participants were diagnosed with dementia and 2110 died. Analyses adjusted for age, sex, ethnicity, education, and SEP showed smokers (hazard ratio [HR] 1.36 [95% CI 1.10-1.68]) but not ex-smokers (HR 0.95 [95% CI 0.79-1.14]) to have a higher risk of dementia compared to never-smokers; similar results for smoking were obtained for pack-years of smoking and smoking history score. Mediation analysis showed low SEP to be associated with higher risk of dementia (HRs between 1.97 and 2.02, depending on the measure of smoking in the model); estimate for the mediation effect was 16% for smoking status (Indirect Effect HR 1.09 [95% CI 1.03-1.15]), 7% for pack-years of smoking (Indirect Effect HR 1.03 [95% CI 1.01 -1.06]) and 11% for smoking history score (Indirect Effect HR 1.06 [95% CI 1.02-1.10]). Interpretation Our findings suggest that part of the social inequalities in dementia is mediated by smoking.Funding NIHCopyright (c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) The Health 2022;23: Published https://doi.org/10.1016/j. lanepe.2022.100516Peer reviewe

Combined effect of physical activity and leisure time sitting on long-term risk of incident obesity and metabolic risk factor clustering

Aims/hypothesis Our study aimed to investigate the combined effects of moderate-to-vigorous physical activity and leisure time sitting on the long-term risk of obesity and clustering of metabolic risk factors. Methods The duration of moderate and vigorous physical activity and of leisure time sitting was assessed by questionnaire between 1997 and 1999 among 3,670 participants from the Whitehall II cohort study (73% male; mean age 56 years). Multivariable-adjusted logistic regression models examined associations of physical activity and leisure time sitting tertiles with odds of incident obesity (BMI ≥ 30 kg/m2) and incident metabolic risk factor clustering (two or more of the following: low HDL-cholesterol, high triacylglycerol, hypertension, hyperglycaemia, insulin resistance) at 5 and 10 year follow-ups. Results Physical activity, but not leisure time sitting, was associated with incident obesity. The lowest odds of incident obesity after 5 years were observed for individuals reporting both high physical activity and low leisure time sitting (OR = 0.26; 95% CI 0.11, 0.64), with weaker effects after 10 years. Compared with individuals in the low physical activity/high leisure time sitting group, those with intermediate levels of both physical activity and leisure time sitting had lower odds of incident metabolic risk factor clustering after 5 years (OR 0.53; 95% CI 0.36, 0.78), with similar odds after 10 years. Conclusions/interpretation Both high levels of physical activity and low levels of leisure time sitting may be required to substantially reduce the risk of obesity. Associations with developing metabolic risk factor clustering were less clear

Association between kidney function and incidence of dementia : 10-year follow-up of the Whitehall II cohort study

Peer reviewe

Association of sleep duration in middle and old age with incidence of dementia

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 (7h) 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.Peer reviewe

Healthy obesity and objective physical activity

Background: Disease risk is lower in metabolically healthy obese adults than in their unhealthy obese counterparts. Studies considering physical activity as a modifiable determinant of healthy obesity have relied on self-reported measures, which are prone to inaccuracies and do not capture all movements that contribute to health. Objective: We aimed to examine differences in total and moderate-to-vigorous physical activity between healthy and unhealthy obese groups by using both self-report and wrist-worn accelerometer assessments. Design: Cross-sectional analyses were based on 3457 adults aged 60–82 y (77% male) participating in the British Whitehall II cohort study in 2012–2013. Normal-weight, overweight, and obese adults were considered “healthy” if they had <2 of the following risk factors: low HDL cholesterol, hypertension, high blood glucose, high triacylglycerol, and insulin resistance. Differences across groups in total physical activity, based on questionnaire and wrist-worn triaxial accelerometer assessments (GENEActiv), were examined by using linear regression. The likelihood of meeting 2010 World Health Organization recommendations for moderate-to-vigorous activity (≥2.5 h/wk) was compared by using prevalence ratios. Results: Of 3457 adults, 616 were obese [body mass index (in kg/m2) ≥30]; 161 (26%) of those were healthy obese. Obese adults were less physically active than were normal-weight adults, regardless of metabolic health status or method of physical activity assessment. Healthy obese adults had higher total physical activity than did unhealthy obese adults only when assessed by accelerometer (P = 0.002). Healthy obese adults were less likely to meet recommendations for moderate-to-vigorous physical activity than were healthy normal-weight adults based on accelerometer assessment (prevalence ratio: 0.59; 95% CI: 0.43, 0.79) but were not more likely to meet these recommendations than were unhealthy obese adults (prevalence ratio: 1.26; 95% CI: 0.89, 1.80). Conclusions: Higher total physical activity in healthy than in unhealthy obese adults is evident only when measured objectively, which suggests that physical activity has a greater role in promoting health among obese populations than previously thought

Segmenting accelerometer data from daily life with unsupervised machine learning

Purpose: Accelerometers are increasingly used to obtain valuable descriptors of physical activity for health research. The cut-points approach to segment accelerometer data is widely used in physical activity research but requires resource expensive calibration studies and does not make it easy to explore the information that can be gained for a variety of raw data metrics. To address these limitations, we present a data-driven approach for segmenting and clustering the accelerometer data using unsupervised machine learning. Methods: The data used came from five hundred fourteen-year-old participants from the Millennium cohort study who wore an accelerometer (GENEActiv) on their wrist on one weekday and one weekend day. A Hidden Semi-Markov Model (HSMM), configured to identify a maximum of ten behavioral states from five second averaged acceleration with and without addition of x, y, and z-angles, was used for segmenting and clustering of the data. A cut-points approach was used as comparison. Results: Time spent in behavioral states with or without angle metrics constituted eight and five principal components to reach 95% explained variance, respectively; in comparison four components were identified with the cut-points approach. In the HSMM with acceleration and angle as input, the distributions for acceleration in the states showed similar groupings as the cut-points categories, while more variety was seen in the distribution of angles. Conclusion: Our unsupervised classification approach learns a construct of human behavior based on the data it observes, without the need for resource expensive calibration studies, has the ability to combine multiple data metrics, and offers a higher dimensional description of physical behavior. States are interpretable from the distributions of observations and by their duration

Leisure time physical activity and subsequent physical and mental health functioning among midlife Finnish, British and Japanese employees: a follow-up study in three occupational cohorts

OBJECTIVES: The aim of this study was to examine whether leisure time physical activity contributes to subsequent physical and mental health functioning among midlife employees. The associations were tested in three occupational cohorts from Finland, Britain and Japan. DESIGN: Cohort study. SETTING: Finland, Britain and Japan. PARTICIPANTS: Prospective employee cohorts from the Finnish Helsinki Health Study (2000-2002 and 2007, n=5958), British Whitehall II study (1997-1999 and 2003-2004, n=4142) and Japanese Civil Servants Study (1998-1999 and 2003, n=1768) were used. Leisure time physical activity was classified into three groups: inactive, moderately active and vigorously active. PRIMARY OUTCOME MEASURE: Mean scores of physical and mental health functioning (SF-36) at follow-up were examined. RESULTS: Physical activity was associated with better subsequent physical health functioning in all three cohorts, however, with varying magnitude and some gender differences. Differences were the clearest among Finnish women (inactive: 46.0, vigorously active: 49.5) and men (inactive: 47.8, active vigorous: 51.1) and British women (inactive: 47.3, active vigorous: 50.4). In mental health functioning, the differences were generally smaller and not that clearly related to the intensity of physical activity. Emerging differences in health functioning were relatively small. CONCLUSIONS: Vigorous physical activity was associated with better subsequent physical health functioning in all three cohorts with varying magnitude. For mental health functioning, the intensity of physical activity was less important. Promoting leisure time physical activity may prove useful for the maintenance of health functioning among midlife employees.Peer reviewe

Association of ideal cardiovascular health at age 50 with incidence of dementia : 25 year follow-up of Whitehall II cohort study

OBJECTIVES To examine the association between the Life Simple 7 cardiovascular health score at age 50 and incidence of dementia. DESIGN Prospective cohort study. SETTING Civil service departments in London (Whitehall II study; study inception 1985-88). PARTICIPANTS 7899 participants with data on the cardiovascular health score at age 50. EXPOSURES The cardiovascular health score included four behavioural (smoking, diet, physical activity, body mass index) and three biological (fasting glucose, blood cholesterol, blood pressure) metrics, coded on a three point scale (0, 1, 2). The cardiovascular health score was the sum of seven metrics (score range 0-14) and was categorised into poor (scores 0-6), intermediate (7-11), and optimal (12-14) cardiovascular health. MAIN OUTCOME MEASURE Incident dementia, identified through linkage to hospital, mental health services, and mortality registers until 2017. RESULTS 347 incident cases of dementia were recorded over a median follow-up of 24.7 years. Compared with an incidence rate of dementia of 3.2 (95% confidence interval 2.5 to 4.0) per 1000 person years among the group with poor cardiovascular health, the absolute rate differences per 1000 person years were -1.5 (95% confidence interval -2.3 to -0.7) for the group with intermediate cardiovascular health and -1.9 (-2.8 to -1.1) for the group with optimal cardiovascular health. Higher cardiovascular health score was associated with a lower risk of dementia (hazard ratio 0.89 (0.85 to 0.95) per 1 point increment in the cardiovascular health score). Similar associations with dementia were observed for the behavioural and biological subscales (hazard ratios per 1 point increment in the subscores 0.87 (0.81 to 0.93) and 0.91 (0.83 to 1.00), respectively). The association between cardiovascular health at age 50 and dementia was also seen in people who remained free of cardiovascular disease over the follow-up (hazard ratio 0.89 (0.84 to 0.95) per 1 point increment in the cardiovascular health score). CONCLUSION Adherence to the Life Simple 7 ideal cardiovascular health recommendations in midlife was associated with a lower risk of dementia later in life.Peer reviewe

Physical Activity, Sedentary Behavior, and Long-Term Changes in Aortic Stiffness: The Whitehall II Study.

BACKGROUND: Physical activity is associated with reduced cardiovascular disease risk, mainly through effects on atherosclerosis. Aortic stiffness may be an alternative mechanism. We examined whether patterns of physical activity and sedentary behavior are associated with rate of aortic stiffening. METHODS AND RESULTS: Carotid-femoral pulse wave velocity (PWV) was measured twice using applanation tonometry at mean ages 65 (in 2008/2009) and 70 (in 2012/2013) years in the Whitehall-II study (N=5196). Physical activity was self-reported at PWV baseline (2008/2009) and twice before (in 1997/1999 and 2002/2003). Sedentary time was defined as sitting time watching television or at work/commute. Linear mixed models adjusted for metabolic and lifestyle risk factors were used to analyze PWV change. Mean (SD) PWV (m/s) was 8.4 (2.4) at baseline and 9.2 (2.7) at follow-up, representing a 5-year increase of 0.76 m/s (95% CI 0.69, 0.83). A smaller 5-year increase in PWV was observed for each additional hour/week spent in sports activity (-0.02 m/s [95% CI -0.03, -0.001]) or cycling (-0.02 m/s [-0.03, -0.008]). Walking, housework, gardening, or do-it-yourself activities were not significantly associated with aortic stiffening. Each additional hour/week spent sitting was associated with faster PWV progression in models adjusted for physical activity (0.007 m/s [95% CI 0.001, 0.013]). Increasing physical activity over time was associated with a smaller subsequent increase in PWV (-0.16 m/s [-0.32, -0.002]) compared with not changing activity levels. CONCLUSIONS: Higher levels of moderate-to-vigorous physical activity and avoidance of sedentary behavior were each associated with a slower age-related progression of aortic stiffness independent of conventional vascular risk factors.The Whitehall II study is supported by grants from the British Heart Foundation (RG/13/2/30098 and RG/16/11/32334), British Medical Research Council (K013351), and the US National Institute on Aging (R01AG013196 and R01AG034454). Brunner is supported by the British Heart Foundation (RG/13/2/30098 and RG/16/11/32334) and the European Commission (FP7 project no. 613598). Kivim€aki is supported by a professorial fellowship from the Economic and Social Research Council, and NordForsk, the Nordic Programme on Health and Welfare. Wilkinson is a British Heart Foundation senior fellow. McEniery and Wilkinson received support from the Cambridge National Institute for Health Research Biomedical Research Centre