Accelerometers measure the acceleration of the body part they are attached and allow to estimate time spent in activity levels (sedentary behaviour, light, and moderate-to-vigorous physical activity) ...and sleep over a 24-h period for several consecutive days. These advantages come with the challenges to analyse the large amount of data while integrating dimensions of both physical activity/sedentary behaviour and sleep domains. This commentary raises the questions of 1) how to classify sleep breaks (i.e. wake after sleep onset) during the night within the 24-h movement behaviour framework and 2) how to assess their impact on health while also accounting for night time sleep duration and time in sedentary behaviour and physical activity during the day. The authors advocate for future collaborations between researchers from the physical activity/sedentary behaviour and sleep research fields to ensure appropriate analysis and interpretation of the tremendous amount of data recorded by the newer generation accelerometers. This is the only way forward to provide meaningfully accurate evidence to inform future 24-h movement behaviour guidelines.
ObjectivesWe identified profiles of wake-time movement behaviours (sedentary behaviours, light intensity physical activity and moderate-to-vigorous physical activity) based on accelerometer-derived ...features among older adults and then examined their association with all-cause mortality.MethodsData were drawn from a prospective cohort of 3991 Whitehall II accelerometer substudy participants aged 60–83 years in 2012–2013. Daily movement behaviour profiles were identified using k-means cluster analysis based on 13 accelerometer-assessed features characterising total duration, frequency, bout duration, timing and activity intensity distribution of movement behaviour. Cox regression models were used to assess the association between derived profiles and mortality risk.ResultsOver a mean follow-up of 8.1 (SD 1.3) years, a total of 410 deaths were recorded. Five distinct profiles were identified and labelled as ‘active’ (healthiest), ‘active sitters’, ‘light movers’, ‘prolonged sitters’, and ‘most sedentary’ (most deleterious). In model adjusted for sociodemographic, lifestyle, and health-related factors, compared with the ‘active’ profile, ‘active sitters’ (HR 1.57, 95% CI 1.01 to 2.44), ‘light movers’ (HR 1.75, 95% CI 1.17 to 2.63), ‘prolonged sitters’ (HR 1.67, 95% CI 1.11 to 2.51), ‘most sedentary’ (HR 3.25, 95% CI 2.10 to 5.02) profiles were all associated with a higher risk of mortality.ConclusionGiven the threefold higher mortality risk among those with a ‘most sedentary’ profile, public health interventions may target this group wherein any improvement in physical activity and sedentary behaviour might be beneficial.
A U- or J-shaped association between BMI and different post-stroke outcomes is suggested. Thus, the aim is to evaluate the association between BMI with ADL, IADL and mobility limitations in the ...ageing post-stroke population at different ages, as well as the differences in this association by sex.
A total of 5,468 participants with stroke and 21,872 without stroke over 50 years of age were assessed for the number of limitations in basic or instrumental activities of daily living (ADL/IADL) as well as mobility tasks. The association between BMI at the interview (continuous time-dependent variable) and the level of limitations was assessed using a linear mixed model stratified by sex and stroke status.
The association between BMI and ADL/IADL and mobility limitations were found to be significant in both men and women regardless of stroke status (p<0.001 for all). The association differs between those who have suffered a stroke and those who have not (p<0.001 for all). In ADL/IADL limitations, men with stroke showed a transition from an inverted J-shape to a U-shape association with age. In women, the BMI showed a less pronounced association between BMI and ADL/IADL limitations compared to men but with similar trends. A effect of sex was observed in the association between BMI and mobility, with women with and without stroke showing a linear association that differed from the inverted J-shaped or U-shaped association of men.
Our results suggest that BMI is associated with limitations in ADL, IADL and mobility in stroke patients. In addition, this association differs between men and women and is also influenced by age.
Previous research suggests an inconsistent association between Metabolic syndrome (MetS) and incident dementia. We examined the role of number of MetS components and age at their assessment for ...incident dementia.
MetS components (fasting glucose, triglycerides, waist circumference, blood pressure, and HDL cholesterol) on 7,265, 6,660, and 3,608 participants at <60, 60 to <70, and ≥70 years of age were used to examine associations with incident dementia using cause-specific Cox regression.
Analyses of MetS measured at <60, 60 to <70, and ≥70 years involved 393 (5.4%), 497 (7.5%), and 284 (7.9%) dementia cases over a median follow-up of 20.8, 10.4, and 4.2 years, respectively. Every additional MetS component before 60 (hazard ratio HR 1.13 95% CI 1.05, 1.23) and 60 to <70 (HR 1.08 95% CI 1.00, 1.16) but not ≥70 years (HR 1.04 95% CI 0.96, 1.13) was associated with higher dementia risk. MetS defined conventionally (≥3 components) before 60 years (HR 1.23 95% CI 0.96, 1.57), between 60 and 70 years (HR 1.14 95% CI 0.91, 1.42), or >70 years of age (HR 1.10 95% CI 0.86, 1.40) was not associated with incident dementia. Multistate models showed higher risk of dementia in those with ≥1 (HR 1.99 95% CI 1.08, 3.66) and ≥2 MetS components (HR 1.69 95% CI 1.12, 2.56) before 60 years of age, even when they remained free of cardiovascular disease over the follow-up.
Risk of incident dementia increases with every additional MetS component present in midlife rather than after accumulation of three components; only part of this risk is mediated by cardiovascular disease.
Abstract
Background
We examined associations of total duration and pattern of accumulation of objectively measured sedentary behavior (SB) with incident cardiovascular disease (CVD) and all-cause ...mortality among older adults.
Methods
Total sedentary time and 8 sedentary accumulation pattern metrics were extracted from accelerometer data of 3 991 Whitehall II study participants aged 60–83 years in 2012–2013. Incident CVD and all-cause mortality were ascertained up to March 2019.
Results
Two hundred and ninety-nine CVD cases and 260 deaths were recorded over a mean (standard deviation SD) follow-up of 6.2 (1.3) and 6.4 (0.8) years, respectively. Adjusting for sociodemographic and behavioral factors, 1-SD (100.2 minutes) increase in total sedentary time was associated with 20% higher CVD risk (hazard ratio 95% confidence interval: 1.20 1.05–1.37). More fragmented SB was associated with reduced CVD risk (eg, 0.86 0.76–0.97 for 1-SD 6.2 increase in breaks per sedentary hour). Associations were not evident once health-related factors and moderate-to-vigorous physical activity (MVPA) were considered. For all-cause mortality, associations with more fragmented SB (eg, 0.73 0.59–0.91 for breaks per sedentary hour) were found only among the youngest older group (<74 years; p for interaction with age < .01) independently from all covariates.
Conclusions
In this study, no associations of total sedentary time and sedentary accumulation patterns with incident CVD and all-cause mortality were found in the total sample once MVPA was considered. Our findings of reduced mortality risk with less total and more fragmented SB independent from MVPA among individuals <74 years need to be replicated to support the recent recommendations to reduce and fragment SB.
Abstract INTRODUCTION Cognitive reserve might mitigate the risk of Alzheimer's dementia among memory clinic patients. No study has examined the potential modifying role of stress on this relation. ...METHODS We examined cross‐sectional associations of the cognitive reserve index (CRI; education, occupational complexity, physical and leisure activities, and social health) with cognitive performance and AD‐related biomarkers among 113 memory clinic patients. The longitudinal association between CRI and cognition over a 3‐year follow‐up was assessed. We examined whether associations were influenced by perceived stress and five measures of diurnal salivary cortisol. RESULTS Higher CRI scores were associated with better cognition. Adjusting for cortisol measures reduced the beneficial association of CRI on cognition. A higher CRI score was associated with better working memory in individuals with higher (favorable) cortisol AM/PM ratio, but not among individuals with low cortisol AM/PM ratio. No association was found between CRI and AD‐related biomarkers. DISCUSSION Physiological stress reduces the neurocognitive benefits of cognitive reserve among memory clinic patients. Highlights Physiological stress may reduce the neurocognitive benefits accrued from cognitively stimulating and enriching life experiences (cognitive reserve CR) in memory clinic patients. Cortisol awakening response modified the relation between CR and P‐tau 181 , a marker of Alzheimer's disease (AD). Effective stress management techniques for AD and related dementia prevention are warranted.
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