Sleep, physical activity, sedentary behavior, and risk of incident dementia: a prospective cohort study of 431,924 UK Biobank participants

Sleep Quality Moderates the Associations between Cardiorespiratory Fitness and Hippocampal and Entorhinal Volume in Middle-Aged and Older Adults

INTRODUCTION/PURPOSE

As individuals age, the entorhinal cortex (ERC) and hippocampus-crucial structures for memory-tend to atrophy, with related cognitive decline. Simultaneously, lifestyle factors that can be modified, such as exercise and sleep, have been separately linked to slowing of brain atrophy and functional decline. However, the synergistic impact of fitness and sleep on susceptible brain structures in aging adults remains uncertain.

METHODS

We examined both independent and interactive associations of fitness and subjective sleep quality with regard to ERC thickness and hippocampal volume in 598 middle-aged and older adults from the Human Connectome Lifespan Aging Project. Cardiorespiratory fitness was assessed using the 2-min walk test, whereas subjective sleep quality was measured with the continuous Pittsburgh Sleep Quality Index global score. High-resolution structural magnetic resonance imaging was used to examine mean ERC thickness and bilateral hippocampal volume. Through multiple linear regression analyses, we investigated the moderating effects of subjective sleep quality on the association between fitness and brain structure, accounting for age, sex, education, body mass index, gait speed, and subjective physical activity.

RESULTS

We found that greater cardiorespiratory fitness, but not subjective sleep quality, was positively associated with bilateral hippocampal volume and ERC thickness. Notably, significant interaction effects suggest that poor subjective sleep quality was associated with a weaker association between fitness and both hippocampal volume and ERC thickness.

CONCLUSIONS

Findings suggest the potential importance of both cardiorespiratory fitness and subjective sleep quality in preserving critical, age-vulnerable brain structures. Interventions targeting brain health should consider potential combined effects of sleep and fitness on brain health.

Associations between Recreational Screen Time and Brain Health in Middle-Aged and Older Adults: A Large Prospective Cohort Study

OBJECTIVES

To investigate the associations of recreational screen time with risks of brain-related disorders (dementia, stroke, and Parkinson's disease) and neuroimaging features.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

A total of 407,792 participants from the UK Biobank who were free of dementia, stroke, or Parkinson's disease at enrollment (2006-2010).

METHODS

TV viewing and time spent using the computer were self-reported at baseline. Among a subsample of 40,692 participants, neuroimaging features were measured by magnetic resonance imaging in 2014. Data were analyzed using Cox proportional hazard models, restricted cubic spline models, and general linear regression models.

RESULTS

During a median follow-up of 12.6 years, 5227 incident dementia, 6822 stroke, and 2308 Parkinson's disease cases were identified. Compared with TV viewing >0-1 h/day, watching TV ≥5 h/day was associated with higher risks of dementia [hazard ratio (HR), 1.44; 95% confidence interval (CI), 1.28-1.62], stroke (HR, 1.12; 95% CI, 1.01-1.25), and Parkinson's disease (HR, 1.28; 95% CI, 1.06-1.54). Moreover, we observed inverse associations between TV viewing time and both gray matter volume and hippocampus volume (Ptrend <.001). However, we did not observe the significant associations between discretional computer use and brain-related disorders or neuroimaging features.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that high TV viewing time is associated with increased risk of various brain-related disorders, highlighting recreational TV viewing could have an important impact on brain-related health.

Association between grip strength and walking pace with incidence of degenerative cervical myelopathy: a UK biobank observational study

PURPOSE

This study investigates the association between handgrip strength, walking pace, and the incidence of degenerative cervical myelopathy (DCM) using the UK Biobank dataset.

METHODS

We analyzed data from 364,716 UK Biobank participants without prior neurological conditions. Handgrip strength was measured with a dynamometer, and walking pace was self-reported. Cox proportional hazards models assessed hazard ratios (HRs) and 95% confidence intervals (CIs) for DCM development.

RESULTS

The cohort, with an average age of 56.2 years (SD, 8.1) and 47.4% male, was followed for a median of 12.6 years. During this period, 3,993 participants (1.1%) developed DCM. A significant inverse correlation was found between handgrip strength and DCM incidence (P for trend < 0.001), with decreasing HRs for DCM across quartiles of increasing grip strength: HRs were 0.70 (95% CI: 0.64-0.76), 0.62 (95% CI: 0.57-0.68), and 0.59 (95% CI: 0.54-0.66) for the second, third, and fourth quartiles, respectively. Participants with average or brisk walking paces had a lower DCM risk (HR, 0.55; 95% CI: 0.50-0.61 and HR, 0.48; 95% CI: 0.43-0.54) compared to slow walkers. The greatest risk reduction was in those with both higher handgrip strength and faster pace (HR, 0.39; 95% CI: 0.34-0.44).

CONCLUSIONS

Handgrip strength and walking pace are inversely associated with DCM incidence, suggesting their potential as cost-effective screening tools for identifying individuals at risk for DCM.

Association of past and current sleep duration with structural brain differences: A large population-based study from the UK Biobank

OBJECTIVE

This study aimed to examine the association between past/current sleep duration and macro-/micro-structural brain outcomes and explore whether hypertension or social activity plays a role in such association.

METHODS

Within the UK Biobank, 40 436 dementia-free participants (age 40-70 years) underwent a baseline assessment followed by a brain magnetic resonance imaging (MRI) scan 9 years later. Past (baseline) and current (MRI scans) sleep duration (hours/day) were recorded and classified as short (≤5), intermediate (6-8), and long (≥9). Brain structural volumes and diffusion markers were assessed by MRI scans.

RESULTS

Compared with past intermediate sleep, past short sleep was related to smaller cortex volumes (standardized β [95 % CI]: -0.04 [-0.07, -0.02]) and lower regional fractional anisotropy (FA) (-0.08 [-0.13, -0.03]), while past long sleep was related to smaller regional subcortical volumes (standardized β: -0.04 to -0.07 for thalamus, accumbens, and hippocampus). Compared to current intermediate sleep, current short sleep was associated with smaller cortex volumes (-0.03 [-0.05, -0.01]), greater white matter hyperintensities (WMH) volumes (0.04 [0.01, 0.08]), and lower regional FA (-0.07 [-0.11, -0.02]). However, current long sleep was related to smaller total brain (-0.03 [-0.05, -0.02]), grey matter (-0.05 [-0.07, -0.03]), cortex (-0.05 [-0.07, -0.03]), regional subcortical volumes [standardized β: -0.05 to -0.09 for putamen, thalamus, hippocampus, and accumbens]), greater WMH volumes (0.06 [0.03, 0.09]), as well as lower regional FA (-0.05 [-0.09, -0.02]). The association between current long sleep duration and poor brain health was stronger among people with hypertension or low frequency of social activity (all Pinteraction <0.05).

CONCLUSIONS

Both past and current short/long sleep are associated with smaller brain volume and poorer white matter health in the brain, especially in individuals with hypertension and low frequency of social activity. Our findings highlight the need to maintain 6-8 h' sleep duration for healthy brain aging.

Association between garden work and risk of incident dementia in an older population in China: a national cohort study

OBJECTIVES

Evidence on the association between garden work and risk of incident dementia in the older Chinese population is limited. This study aimed to explore the association between the frequency of garden work and risk of incident dementia in an older population in China.

STUDY DESIGN

This was a national cohort study.

METHODS

This study analysed data from 8676 participants (median age: 86 years) from the Chinese Longitudinal Healthy Longevity Survey. Cox proportional hazard models were used to assess the association between the frequency of garden work and risk of incident dementia using hazard ratios (HRs) and 95% confidence intervals (CIs). Multiplicative and additive interaction effects were calculated between the frequency of garden work and age, sex or residence on incident dementia; subgroup analyses of the association were also conducted by age, sex and residence. In addition, sensitivity analyses were performed to assess the robustness of the results.

RESULTS

During 4.31 years (median) of follow-up, 633 participants developed dementia. Compared with participants who did not engage in garden work, the adjusted risk of incident dementia for those who regularly or almost daily engaged in garden work decreased by 28% (HR = 0.72, 95% CI: 0.57-0.93). An additive interaction effect between frequency of garden work and age on incident dementia was observed, with subgroup analyses demonstrating similar statistically significant associations among participants aged ≥85 years, women and city or town residents. Sensitivity analyses were consistent with the primary analysis in the present study.

CONCLUSIONS

Frequent engagement in garden work may be associated with a reduced risk of dementia and may be an effective measure to prevent incident dementia in the older population in China.

Sleep and physical activity measures are associated with resting-state network segregation in non-demented older adults

Greater physical activity and better sleep are associated with reduced risk of cognitive decline and dementia among older adults, but little is known about their combined associations with measures of brain function and neuropathology. This study investigated potential independent and interactive cross-sectional relationships between actigraphy-estimated total volume of physical activity (TVPA) and sleep patterns [i.e., total sleep time (TST), sleep efficiency (SE)] with resting-state functional magnetic resonance imaging (rs-fMRI) measures of large scale network connectivity and positron emission tomography (PET) measures of amyloid-β. Participants were 135 non-demented older adults from the BIOCARD study (116 cognitively normal and 19 with mild cognitive impairment; mean age = 70.0 years). Using multiple linear regression analyses, we assessed the association between TVPA, TST, and SE with connectivity within the default-mode, salience, and fronto-parietal control networks, and with network modularity, a measure of network segregation. Higher TVPA and SE were independently associated with greater network modularity, although the positive relationship of SE with modularity was only present in amyloid-negative individuals. Additionally, higher TVPA was associated with greater connectivity within the default-mode network, while greater SE was related to greater connectivity within the salience network. In contrast, longer TST was associated with lower network modularity, particularly among amyloid-positive individuals, suggesting a relationship between longer sleep duration and greater network disorganization. Physical activity and sleep measures were not associated with amyloid positivity. These data suggest that greater physical activity levels and more efficient sleep may promote more segregated and potentially resilient functional networks and increase functional connectivity within specific large-scale networks and that the relationship between sleep and functional networks connectivity may depend on amyloid status.

The association of sleep duration and leukocyte telomere length in middle-aged and young-old adults: A cross-sectional study of UK Biobank

BACKGROUND

The relationships between sleep duration and aging-associated diseases are intricate. Leukocyte telomere length (LTL) is a biomarker of aging, while the association of sleep duration and LTL is unclear.

METHODS

The 310,091 study participants from UK Biobank were enrolled in this cross-sectional study. Restricted cubic splines (RCS) analysis was firstly performed to assess the nonlinear relationship between sleep duration and LTL. Sleep duration was then categorized into three groups: <7 h (short sleep duration), 7-8 h (reference group), and >8 h (long sleep duration) and multiple linear regression was applied to analyze the association of short sleep and long sleep duration with LTL. We further performed subgroup analyses stratified by sex, age, chronotype and snoring.

RESULTS

RCS showed an inverted J-shaped relationship between sleep duration and LTL. Compared with the reference group, the inverse association of long sleep duration and LTL was statistically significant in fully-adjusted model (P = 0.001). Subgroup analyses showed that this association was more apparent in people over 50 years (51-60 y: P = 0.002; >60 y: P = 0.005), in men (P = 0.022), and in people preferred evening chronotype (P = 0.001).

CONCLUSION

Compared with participants sleeping 7-8 h, those sleep longer than 8 h had shorter LTL in middle-aged and young-old adults. The negative association between long sleep duration and LTL was more apparent in older people, in men, and in people preferred evening chronotype.

Relationship of microvascular complications and healthy lifestyle with all-cause and cardiovascular mortality in women compared with men with type 2 diabetes

BACKGROUND

Sex differences exist in the prevalence of microvascular disease (MVD) and healthy-lifestyle adherence. Whether MVD and healthy lifestyles are associated with mortality risk similarly for women and men who have type 2 diabetes mellitus (T2DM) remains unknown.

METHODS

The present study included 9992 women and 15,860 men with T2DM from the UK Biobank. MVDs included retinopathy, peripheral neuropathy, and chronic kidney disease. Healthy lifestyle factors consisted of ideal BMI, nonsmoking, healthy diet, regular exercise, and appropriate sleep duration. Sex-specific hazard ratios (HRs) of mortality associated with the MVDs or healthy lifestyles were calculated and women-to-men ratio of HRs (RHR) were further estimated, after multivariable adjustment for potential confounders.

RESULTS

During a median of 12.7 years of follow-up, 4346 (1202 in women) all-cause and 1207 (254 in women) CVD deaths were recorded. The adjusted HRs (95% CI) of all-cause mortality for 1 additional increment of the MVDs were 1.71 (1.55, 1.88) for women and 1.48 (1.39, 1.57) for men, with an RHR of 1.16 (1.03, 1.30). The corresponding RHR was 1.36 (1.09, 1.69) for cardiovascular mortality. Adhering to a healthy lifestyle (≥4 vs. ≤1 lifestyle factor) was associated with an approximately 60%-70% lower risk of all-cause and cardiovascular mortality without sex differences (P-interaction >0.70). Furthermore, as compared with having no MVD and an unfavorable lifestyle, having ≥2 MVDs but a favorable lifestyle was not associated with a higher risk of all-cause mortality either in women (HR = 0.88; 95% CI: 0.49, 1.60) or in men (HR = 0.95; 95% CI: 0.64, 1.40), similarly when considering cardiovascular mortality.

CONCLUSIONS

In T2DM, while MVDs are more strongly associated with mortality risk in women than in men, adhering to a favorable lifestyle is associated with a substantially lower risk of mortality and may eliminate the detrimental impact of MVDs in both sexes.

Individual sleep need is flexible and dynamically related to cognitive function

Given that sleep deprivation studies consistently show that short sleep causes neurocognitive deficits, the effects of insufficient sleep on brain health and cognition are of great interest and concern. Here we argue that experimentally restricted sleep is not a good model for understanding the normal functions of sleep in naturalistic settings. Cross-disciplinary research suggests that human sleep is remarkably dependent on environmental conditions and social norms, thus escaping universally applicable rules. Sleep need varies over time and differs between individuals, showing a complex relationship with neurocognitive function. This aspect of sleep is rarely addressed in experimental work and is not reflected in expert recommendations about sleep duration. We recommend focusing on the role of individual and environmental factors to improve our understanding of the relationship between human sleep and cognition.

Sedentary behavior and the combination of physical activity associated with dementia, functional disability, and mortality: A cohort study of 90,471 older adults in Japan

OBJECTIVE

To examine the associations of sedentary behavior (SB) and the combination of moderate-to-vigorous intensity physical activity (MVPA) with dementia, functional disability, and mortality in older adults, and the heterogeneity in different subpopulations.

METHODS

Nation-wide cohort with 90,471 individuals aged ≥65 years in Japan. SB (<3, 3-<8, and ≥ 8 h per day [h/d]) and MVPA (0, 0 < MVPA<1, and ≥ 1 h/d) were measured in 2016. Long-term care registry-based incidence of outcomes was ascertained through 2021. Cox proportional hazard models were performed.

RESULTS

Compared with SB < 3 h/d group, SB ≥ 8 h/d was associated with higher risks of dementia, functional disability, and mortality with hazard ratios (95% confidence interval) of 1.36 (1.22-1.52), 1.32 (1.19-1.48), and 1.31 (1.18-1.45). The combination of MVPA and SB demonstrated a dose-respond trend of increasing risks of dementia, functional disability, and mortality with increased SB and decreased MVPA, where participants who spent no MVPA with SB ≥ 8 h/d had the highest risks. High MVPA attenuated but didn't eliminate the risks. Participants who spent MVPA≥1 h/d with SB ≥ 8 h/d had comparable risks to those who spent no MVPA with SB < 3 h/d. No heterogeneity was found by MVPA levels, sex, education, comorbidity, and depression conditions.

CONCLUSIONS

Prolonged daily SB was associated with higher risks of dementia, functional disability, and mortality in older adults, regardless of MVPA, sex, education, and chronic conditions. Individuals with high MVPA also face considerable risks when engaging in high SB. High MVPA with high SB revealed a comparable risk to no MVPA with low SB.

Recent advances in understanding of sleep disorders and disturbances for dementia risk and prevention

PURPOSE OF REVIEW

To synthesise the recent work examining the relationship between sleep disturbances and dementia, emphasising studies involving individuals with mild cognitive impairment (MCI) or Alzheimer's disease (AD) and/or those investigating AD biomarkers. Additionally, we provide an update on recent interventions targeting sleep-related issues in older adults with MCI or AD.

RECENT FINDINGS

Various studies have examined obstructive sleep apnoea, sleep duration, and circadian alterations in relation to Alzheimer's pathology and dementia risk, with an emerging body of evidence suggesting that cardiovascular disease, hypertension, glymphatic function, and inflammation might serve as plausible pathophysiological mechanisms contributing to dementia during critical brain periods. Conversely, recent studies investigating insomnia have produced disparate results. Regarding intervention studies, the scarcity of prospective randomised control trials poses a challenge in establishing the benefits of addressing sleep disorders and disturbances.

SUMMARY

Recent work examining the pathophysiological links between sleep and dementia is strongest for obstructive sleep apnoea and sleep duration, while findings in insomnia studies exhibit inconsistency, possibly due to varied associations with dementia among different insomnia subtypes. It is apparent that more longitudinal studies examining the underlying pathophysiological mechanisms are necessary, alongside more rigorous clinical trials. Although some trials are underway in this field, there is still scarcity in trials examining interventions for circadian disturbances.

Association of the Sleep Regularity Index With Incident Dementia and Brain Volume

BACKGROUND AND OBJECTIVES

Irregular sleep may increase the risk of cardiometabolic conditions, but its association with incident dementia is unclear. The aim of this study was to assess the association between sleep regularity, that is, the day-to-day consistency in sleep-wake patterns and the risk of incident dementia and related brain MRI endophenotypes.

METHODS

We used Cox proportional hazard models to investigate the relationships between sleep regularity and incident dementia in 88,094 UK Biobank participants. The sleep regularity index (SRI) was calculated as the probability of being in the same state (asleep/awake) at any 2 time points 24 hours apart, averaged over 7 days of accelerometry.

RESULTS

The mean age of the sample was 62 years (SD = 8), 56% were women, and the median SRI was 60 (SD = 10). There were 480 cases of incident dementia over a median 7.2 years of follow-up. Following adjustments for demographic, clinical, and genetic confounders (APOE ε4), there was a nonlinear association between the SRI and dementia hazard (p [global test of spline term] < 0.001) with hazard ratios (HRs) following a U-shape pattern. HRs, relative to the median SRI, were 1.53 (95% CI 1.24-1.89) for participants with SRI at the 5th percentile (SRI = 41) and 1.16 (95% CI 0.89-1.50) for those with SRI at the 95th percentile (SRI = 71). In a subset with brain MRI (n = 15,263), gray matter and hippocampal volume tended to be lowest at the extremes of the SRI.

DISCUSSION

Sleep regularity displayed a U-shaped association with risk of incident dementia. Irregular sleep may represent a novel dementia risk factor.

Gender-and age-specific associations of sleep duration and quality with cognitive impairment in community-dwelling older adults in Anhui Province, China

Objective

To examine associations of sleep duration and quality with cognitive impairment in older adults and the moderating role of gender and age in these associations.

Methods

This community-based cross-sectional study included 4,837 participants aged 60 years and above. Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination (MMSE), and the participants were grouped based on the presence of cognitive impairment. The duration and quality of sleep were assessed using the Pittsburgh Sleep Quality Index (PSQI). Multivariate logistic regression models were used to analyze associations of sleep duration and quality with cognitive impairment. The role of age and gender in these associations have also been explored.

Results

The age (mean ± SD) of the participants was 71.13 ± 5.50 years. Of all older adults, 1,811 (37.44%) were detected as cognitive impairment, and 1755 (36.8%) had poor sleep quality. Among those with cognitive impairment, 51.09% were female. The proportion of the participants with cognitive impairment is significantly higher in those with symptoms of depression (49.73%, 273/549) (χ2 = 41.275, p < 0.001) than in those without depressive symptoms. After adjustment for multiple confounding factors and the crucial covariate (depressive symptoms), the odds ratios (OR) (95% confidence interval [CI]) of cognitive impairment (with 7-7.9 h regarded as the reference group) for individuals with a sleep duration of <6, 6-6.9, 8-8.9, and ≥ 9 h were 1.280 (1.053-1.557), 1.425 (1.175-1.728), 1.294 (1.068-1.566), and 1.360 (1.109-1.668), respectively. Subgroup analysis showed a V-shaped association between night sleep duration and cognitive impairment in males (p ≤ 0.05), and the association was stronger for individuals aged 60-80 years. With regard to sleep quality, the fully adjusted OR (95%CI) of cognitive impairment were 1.263 (1.108-1.440). According to scores of subscales in the PSQI, daytime dysfunction was associated with an increased risk of cognitive impairment (OR: 1.128, 95%CI: 1.055-1.207). Subgroup analysis also revealed a statistically significant correlation between poor sleep quality (including daytime dysfunction) and cognitive impairment in different gender and age groups, with the association being stronger in females (OR: 1.287, 95%CI: 1.080-1.534) and those aged 81-97 years (OR: 2.128, 95%CI: 1.152-3.934). For cognitive impairment, the group aged 81-97 years with daytime dysfunction was associated with a higher odds ratio than other age groups.

Conclusion

The present study showed that inadequate or excessive sleep was associated with cognitive impairment, especially in males, who exhibited a V-shaped association. Cognitive impairment was also associated with poor sleep quality as well as daytime dysfunction, with females and individuals aged 81-97 years exhibiting the strongest association.

Self-Reported Sleep Duration and Bedtime Are Associated with Dementia Risk in Community-Dwelling People Aged 40-74 Years: The Murakami Cohort Study

Background

Sleep is a potentially modifiable factor associated with dementia, including Alzheimer's disease, but current evidence supporting this is insufficient.

Objective

This study aimed to determine whether sleep duration and bedtime patterns are associated with the risk of dementia among middle-aged and older people.

Methods

This cohort study had an eight-year follow-up period. Participants were 13,601 community-dwelling people aged 40-74 years living in Murakami (Niigata, Japan). Data were collected using a self-administered questionnaire. Predictors were self-reported sleep duration and bedtime, and the outcome was newly-diagnosed dementia determined using the long-term care insurance database. Covariates were demographic characteristics, body mass index, smoking, alcohol consumption, total physical activity, insomnia symptoms, disease history, and either bedtime or sleep duration. Cox proportional hazard models were used to calculate hazard ratios (HRs).

Results

The mean age of participants at baseline was 59.2 years. Over a mean follow-up period of 8.0 years, 319 cases of dementia were observed. A long self-reported sleep duration relative to the reference sleep duration (7 hours) was associated with increased dementia risk, with the "8 hours" group (adjusted HR = 1.30, 95% CI:0.99-1.73) and "≥9 hours" group (adjusted HR = 1.46, 95% CI:1.00-2.15) having an increased risk (marginally significant) relative to the reference group. Early bedtime was associated with increased dementia risk (adjusted p for trend = 0.0010), with the "21 : 00 or earlier" group (adjusted HR = 1.61, 95% CI:1.14-2.28) having an increased risk relative to the reference ("23 : 00").

Conclusions

A long self-reported sleep duration and early bedtime are both associated with increased dementia risk in middle-aged and older people.

Inverse association of glucosamine use and risk of new-onset kidney stones in UK adults with less sedentary time

OBJECTIVE

To assess the association of different sedentary behaviors and glucosamine use with the risk of kidney stones and examine the modification of genetic risk of kidney stones on this association.

METHODS

473,225 participants free of kidney stones at baseline from the UK Biobank were included. Total sedentary time was calculated as the sum of the duration of TV-watching, driving, and non-occupational computer using. The primary outcome was new-onset kidney stones.

RESULTS

During a median follow-up of 12.0 years, 5528 cases of kidney stones were documented. All major sedentary behaviors and total sedentary time were significantly positively related to the risk of kidney stones (All P for trend<0.05). Participants with total sedentary time ≥ 3.5 h/day had a significantly higher risk of new-onset kidney stones (vs. <3.5 h/day [tertile 1]; HR, 1.18; 95%CI,1.10-1.27). Compared with non-users, participants who regularly used glucosamine had a significantly lower risk of new-onset kidney stones in those with total sedentary time < 3.5 h/day (HR, 0.72; 95%CI,0.59-0.86), but not in those with total sedentary time ≥ 3.5 h/day (HR, 0.99; 95%CI,0.91-1.08; P-interaction = 0.001). Among participants with total sedentary time < 3.5 h/day, there was a dose-response relationship of glucosamine use with new-onset kidney stones (P for trend<0.001). Genetic risks of kidney stones did not significantly modify the association.

CONCLUSIONS

TV-watching, driving and non-occupational computer using were all positively associated with the risk of new-onset kidney stones. Glucosamine use was associated with a lower risk of new-onset kidney stones in participants with total sedentary time < 3.5 h/day, following a dose-response relationship.

Trends in deaths and disability-adjusted life-years of stroke attributable to low physical activity worldwide, 1990-2019

BACKGROUND

Low physical activity (LPA) is linked to the risk of stroke, but the disease burden of stroke attributable to LPA needs to be understood to develop effective preventive strategies. We aim to assess spatiotemporal trends in the global burden of stroke attributable to LPA from 1990 to 2019.

METHODS

Based on the Global Burden of Disease, Injuries, and Risk Factors Study, our research examined deaths, the Disability-Adjusted Life Years (DALYs), the Age-Standardized Mortality Rate (ASMR), the Age-Standardized DALY Rate (ASDR), and the Estimated Annual Percentage Change (EAPC) for stroke attributable to LPA.

RESULTS

Deaths and DALYs were on the rise worldwide from 1990 to 2019, with increases of 72.72% for the former and 67.41% for the latter; ASMR and ASDR decreased, with the ASMR-related EAPC of -1.61 (95% CI:-1.71--1.5) and ASDR-related EAPC of -1.35 (95% CI:-1.43--1.27); females had more numbers of deaths and DALYs, and the majorities of deaths and DALYs were shared by those aged ≥ 70. The highest burden rates were shared by North Africa, the Middle East, and Tropical Latin America; the ASMR-related EAPC was associated with the ASMR in 1990 (R = -0.26, P < 0.001) and the Socio-Demographic Index (SDI) across different countries in 2019 (R = -0.61, P < 0.001), respectively, and such patterns were similar to what ASDR and the ASDR-related EAPC had; the Human Development Index (HDI) in 2019 was associated with the ASMR-related EAPC (R = 0.63, P < 0.001) and the ASDR-related EAPC across different countries (R = -0.62, P < 0.001), respectively.

CONCLUSIONS

Globally, deaths and DALYs of stroke attributable to LPA were on the rise, although their age-standardized rates presented downward over the past three decades; the burden of stroke attributable to LPA showed upward trends especially in those aged ≥ 70 and females in the regions of East Asia, North Africa, and the Middle East, which need more attention to the effects of physical activity on health interventions.

Different types of screen time, physical activity, and incident dementia, Parkinson's disease, depression and multimorbidity status

BACKGROUND

Several previous studies have shown that excessive screen time is associated with an increased prevalence of dementia, Parkinson's disease (PD), and depression. However, the results have been inconsistent. This study aimed to prospectively investigate the association between different types of screen time and brain structure, as well as the incidence of dementia, Parkinson's disease, depression, and their multimorbidity status.

METHODS

We included 473,184 participants initially free of dementia, PD, and depression from UK Biobank, as well as 39,652 participants who had magnetic resonance imaging (MRI) data. Screen time exposure variables including TV viewing and computer using were self-reported by participants. Cox proportional hazards regression models were used to estimate the association between different types of screen time and the incidence of dementia, Parkinson's disease, depression, and their multimorbidity status. Multiple linear regression models were used to assess the linear relationship between different types of screen time and MRI biomarkers in a subgroup of participants.

RESULTS

During the follow up, 6,096, 3,061, and 23,700 participants first incident cases of dementia, PD, and depression respectively. For moderate versus the lowest computer uses, the adjusted HRs (95% CIs) were 0.68 (0.64, 0.72) for dementia, 0.86 (0.79, 0.93) for PD, 0.85 (0.83, 0.88) for depression, 0.64 (0.55, 0.74) for dementia and depression multimorbidity, and 0.59 (0.47, 0.74) for PD and depression multimorbidity. The multivariable HRs (95% CIs) for the highest versus the lowest group of TV viewing time were 1.28 (1.17, 1.39) for dementia, 1.16 (1.03, 1.29) for PD, 1.35 (1.29, 1.40) for depression, 1.49 (1.21, 1.84) for dementia and depression multimorbidity, and 1.44 (1.05, 1.97) for PD and depression multimorbidity. Moderate computer using time was negatively associated with white matter hyperintensity volume (β = -0.042; 95% CI -0.067, -0.017), and positively associated with hippocampal volume (β = 0.059; 95% CI 0.034, 0.084). Participants with the highest TV viewing time were negatively associated with hippocampal volume (β = -0.067; 95% CI -0.094, -0.041). In isotemporal substitution analyses, substitution of TV viewing or computer using by equal time of different types of PA was associated with a lower risk of all three diseases, with strenuous sports showing the strongest benefit.

CONCLUSION

We found that moderate computer use was associated with a reduced risk of dementia, PD, depression and their multimorbidity status, while increased TV watching was associated with a higher risk of these disease. Notably, different screen time may affect the risk of developing diseases by influencing brain structures. Replacing different types of screen time with daily-life PA or structured exercise is associated with lower dementia, PD, and depression risk.

No phenotypic or genotypic evidence for a link between sleep duration and brain atrophy

Short sleep is held to cause poorer brain health, but is short sleep associated with higher rates of brain structural decline? Analysing 8,153 longitudinal MRIs from 3,893 healthy adults, we found no evidence for an association between sleep duration and brain atrophy. In contrast, cross-sectional analyses (51,295 observations) showed inverse U-shaped relationships, where a duration of 6.5 (95% confidence interval, (5.7, 7.3)) hours was associated with the thickest cortex and largest volumes relative to intracranial volume. This fits converging evidence from research on mortality, health and cognition that points to roughly seven hours being associated with good health. Genome-wide association analyses suggested that genes associated with longer sleep for below-average sleepers were linked to shorter sleep for above-average sleepers. Mendelian randomization did not yield evidence for causal impacts of sleep on brain structure. The combined results challenge the notion that habitual short sleep causes brain atrophy, suggesting that normal brains promote adequate sleep duration-which is shorter than current recommendations.

Total sleep duration and daytime napping in relation to dementia detection risk: Results from the Million Women Study

INTRODUCTION

There is inconsistent evidence on the associations of sleep duration and daytime napping with dementia risk.

METHODS

In the Million Women Study, a total of 830,716 women (mean age, 60 years) were asked about sleep duration (<7, 7-8, >8 hours) and daytime napping (rarely/never, sometimes, usually) in median year 2001, and were followed for the first hospital record with any mention of dementia. Cox regression estimated dementia detection risk ratios (RRs) during 17-year follow-up in 5-year intervals.

RESULTS

With 34,576 dementia cases, there was strong attenuation over follow-up in the RRs related to long sleep duration (>8 vs 7-8 hours) and usually napping (vs rarely/never). Short sleep duration was modestly, positively associated with dementia in the long term (RR = 1.08, 95% confidence interval [CI] 1.04-1.12).

DISCUSSION

There was little evidence to suggest that long sleep duration and regular napping are associated with long-term dementia risk. Short sleep duration was modestly associated with dementia risk, but residual confounding cannot be excluded.

HIGHLIGHTS

Long sleep duration was not associated with long-term dementia risk. Daytime napping was not associated with long-term dementia risk. There is some evidence for a small higher risk of dementia related to short sleep.

Variety and Duration of Different Sedentary Behaviors, Inflammation, Genetic Susceptibility, and New-Onset Dementia in the Older Population

OBJECTIVES

We aimed to evaluate the relationship of the variety and duration of different sedentary behaviors (TV-watching, driving, and nonoccupational computer use) with the risk of dementia in older participants, and examine whether inflammation and genetic susceptibility may modify the relationship.

DESIGN

A prospective cohort study.

SETTING AND PARTICIPANTS

173,829 older participants (≥60 years) without prior dementia in the UK Biobank were enrolled.

METHODS

A healthy sedentary behavior score was calculated as the number of the 3 major sedentary behaviors with a duration associated with the lowest risk of dementia. The primary outcome was new-onset all-cause dementia.

RESULTS

During a median follow-up of 12.4 years, 4965 (2.9%) participants developed new-onset dementia. There were U-shaped associations for TV-watching and driving time, and a reversed J-shaped association for nonoccupational computer use time with new-onset all-cause dementia, with the lowest dementia risk at >0-<2 hours/day for all the 3 sedentary behaviors. Moreover, a higher healthy sedentary behavior score was significantly associated with a lower risk of all-cause dementia (per 1 score increment: hazard ratio 0.78, 95% CI 0.75-0.81), with a stronger inverse association in those with higher levels of high-sensitivity C-reactive protein and monocytes (both P-interactions <.05). Genetic risks of dementia did not significantly modify the association. Similar trends were found for new-onset Alzheimer's disease and vascular dementia.

CONCLUSIONS AND IMPLICATIONS

The associations between the duration of different sedentary behaviors and new-onset dementia were different in the older population. Moreover, the variety of sedentary behavior was inversely associated with new-onset dementia, especially among those with higher levels of inflammation.

Association between housework and the risk of dementia among older Chinese adults: a prospective cohort study

OBJECTIVES

Physical activity (PA) is known to improve physical functioning and mental health and to reduce the incidence of dementia. However, studies of the effects of non-recreational PA on the incidence of dementia, especially in East Asian populations, remain limited. In this study, we evaluate the association of doing housework with the risk of dementia among participants in the Chinese Longitudinal Healthy Longevity Survey (CLHLS).

METHODS

The analysis was conducted with data from 7,237 CLHLS participants age over 65 obtained in 2008/2009, 2011/2012, 2014, and 2018. The frequency of housework performance was classified into four groups. A Cox proportional-hazards model was used to examine the association of the baseline housework frequency with the incidence of dementia, with adjustment for demographic and socioeconomic characteristics and lifestyle and health conditions.

RESULTS

The adjusted multivariate model showed that the incidence of dementia was lower among participants who did housework almost every day than among those who rarely or never did housework (hazard ratio = 0.49; 95% confidence interval, 0.39-0.61). The subgroup and sensitivity analyses yielded similar results.

CONCLUSION

A high frequency of housework performance was associated with a reduced incidence of dementia among older Chinese adults, especially those who did not exercise regularly. The encouragement of engagement in housework would be a cost-effective measure promoting healthy aging in the Chinese population.

Identifying modifiable factors and their joint effect on dementia risk in the UK Biobank

Previous hypothesis-driven research has identified many risk factors linked to dementia. However, the multiplicity and co-occurrence of risk factors have been underestimated. Here we analysed data of 344,324 participants from the UK Biobank with 15 yr of follow-up data for 210 modifiable risk factors. We first conducted an exposure-wide association study and then combined factors associated with dementia to generate composite scores for different domains. We then evaluated their joint associations with dementia in a multivariate Cox model. We estimated the potential impact of eliminating the unfavourable profiles of risk domains on dementia using population attributable fraction. The associations varied by domain, with lifestyle (16.6%), medical history (14.0%) and socioeconomic status (13.5%) contributing to the majority of dementia cases. Overall, we estimated that up to 47.0%-72.6% of dementia cases could be prevented.

The independent and joint association of accelerometer-measured physical activity and sedentary time with dementia: a cohort study in the UK Biobank

BACKGROUND

Research on the association of physical activity and sedentary time with dementia is accumulating, though elusive, and the interaction effects of the two remain unclear. We analysed the joint associations of accelerometer-measured physical activity and sedentary time with risk of incident dementia (all-cause dementia, Alzheimer's disease and vascular dementia).

METHODS

A total of 90,320 individuals from the UK Biobank were included. Accelerometer-measured total volume of physical activity (TPA) and sedentary time were measured at baseline and dichotomised by median (low TPA [< 27 milli-gravity (milli-g)], high TPA [≥ 27 milli-g]; low sedentary time [< 10.7 h/day], high sedentary time [≥ 10.7 h/day]). Cox proportional hazards models were used to evaluate the joint associations with incident dementia on both additive and multiplicative scales.

RESULTS

During a median follow-up of 6.9 years, 501 cases of all-cause dementia were identified. Higher TPA was associated with a lower risk of all-cause dementia, Alzheimer's disease and vascular dementia; the multivariate adjusted hazard ratios (HRs) (95% CI) per 10 milli-g increase were 0.63 (0.55-0.71), 0.74 (0.60-0.90) and 0.69 (0.51-0.93), respectively. Sedentary time was only found to be linked to all-cause dementia, and the HR for high sedentary time was 1.03 (1.01-1.06) compared with that for low sedentary time. No additive and multiplicative relationship of TPA and sedentary time to incident dementia was found (all P values > 0.05).

CONCLUSION

Higher TPA level was related to a lower risk of incident dementia irrespective of sedentary time, which highlighted the implication of promoting physical activity participation to counteract the potential detrimental effect of sedentary time on dementia.

Association Between 24-Hour Movement Behavior and Cognitive Function in Brazilian Middle-Aged and Older Adults: Findings From the ELSA-Brasil

Background and Objectives

The relationship between 24-hr movement behavior and specific domains of cognitive function is unclear. The purpose of this study was to identify the joint association of daily time spent in light (light-intensity physical activity [LPA]) and moderate-to-vigorous physical activity (MVPA), sedentary behavior (SB), and sleep with cognitive function in middle-aged and older adults.

Research Design and Methods

Cross-sectional data from Wave 3 (2017-2019) of the Brazilian Longitudinal Study of Adult Health were analyzed. The study included adults aged 41-84 years old. Physical activity was assessed using a waist-worn accelerometer. Cognitive function was examined using standardized tests to assess memory, language, and Trail-Making test. Global cognitive function score was calculated by averaging domain-specific scores. Compositional isotemporal substitution models were performed to identify the association between the reallocation of time spent in LPA, MVPA, sleep, and SB with cognitive function.

Results

Participants (n = 8,608) were 55.9% female (mean age 58.9 [8.6] years). Reallocating time from SB to MVPA was associated with higher cognitive function: Reallocating 15 min to MVPA by reducing 5 min from each other behavior was associated with increased odds of better cognitive function in both insufficient (<7 hr/day; odds ratio [OR]: 0.64; 95% confidence interval [CI]: 0.54-0.77) and sufficient (≥7 hr/day; OR: 0.62; 95% CI: 0.58-0.67) sleep groups. Among those with insufficient sleep, reallocating time to MVPA and sleep from SB was associated with higher global cognitive performance.

Discussion and Implications

Small reductions in SB and increments in MVPA were associated with higher cognitive function in middle-aged and older adults.

Lifestyle risks associated with brain functional connectivity and structure

Some lifestyle factors are related to health and brain function and structure, but the brain systems involved are incompletely understood. A general linear model was used to test the associations of the combined and separate lifestyle risk measures of alcohol use, smoking, diet, amounts of physical activity, leisure activity, and mobile phone use, with brain functional connectivity with the high resolution Human Connectome Project (HCP) atlas in 19,415 participants aged 45-78 from the UK Biobank, with replication with HCP data. Higher combined lifestyle risk scores were associated with lower functional connectivity across the whole brain, but especially of three brain systems. Low physical, and leisure and social, activity were associated with low connectivities of the somatosensory/motor cortical regions and of hippocampal memory-related regions. Low mobile phone use, perhaps indicative of poor social communication channels, was associated with low functional connectivity of brain regions in and related to the superior temporal sulcus that are involved in social behavior and face processing. Smoking was associated with lower functional connectivity of especially frontal regions involved in attention. Lower cortical thickness in some of these regions, and also lower subcortical volume of the hippocampus, amygdala, and globus pallidus, were also associated with the sum of the poor lifestyle scores. This very large scale analysis emphasizes how the lifestyle of humans relates to their brain structure and function, and provides a foundation for understanding the causalities that relate to the differences found here in the brains of different individuals.

Effect of replacing television viewing with different intensities of physical activity on COVID-19 mortality risk: Short communication from UK Biobank

AIMS

This study aimed to examine the theoretical effects of replacing television (TV) viewing with different intensities of physical activity on COVID-19 mortality risk using isotemporal substitution models.

METHODS

The analytical sample was composed of 359,756 UK Biobank participants. TV viewing and physical activity were assessed by self-report. Logistic regressions adjusted for covariates were used to model the effects of substituting an hour a day of TV viewing with an hour of walking, moderate-intensity physical activity (MPA) or vigorous-intensity physical activity (VPA) on COVID-19 mortality risk.

RESULTS

From 16 March 2020 to 12 November 2021, there were 879 COVID-19 deaths in the analytical sample. Substituting an hour a day of TV viewing with an hour of walking was associated with a 17% lower risk of COVID-19 mortality (odds ratio (OR)=0.83, 95% confidence interval (CI) 0.74-0.92). In sex-stratified analyses, the same substitution was associated with a lower risk in both men (OR=0.85, 95% CI 0.74-0.96) and women (OR=0.78, 95% CI 0.65-0.95). However, replacing an hour a day of TV viewing with an hour of MPA was only associated with a lower risk in women (OR=0.80, 95% CI 0.65-0.98).

CONCLUSIONS

Replacing TV viewing with walking was associated with a significant reduction in COVID-19 mortality risk. Public health authorities should consider promoting the replacement of TV viewing with walking as a protective strategy against COVID-19 mortality.

Statistical Approaches for the Analysis of Combined Health-Related Factors in Association with Adult Cognitive Outcomes: A Scoping Review

BACKGROUND

Dementia prevention is a global health priority, and there is emerging evidence to support associations between individual modifiable health behaviors and cognitive function and dementia risk. However, a key property of these behaviors is they often co-occur or cluster, highlighting the importance of examining them in combination.

OBJECTIVE

To identify and characterize the statistical approaches used to aggregate multiple health-related behaviors/modifiable risk factors and assess associations with cognitive outcomes in adults.

METHODS

Eight electronic databases were searched to identify observational studies exploring the association between two or more aggregated health-related behaviors and cognitive outcomes in adults.

RESULTS

Sixty-two articles were included in this review. Fifty articles employed co-occurrence approaches alone to aggregate health behaviors/other modifiable risk factors, eight studies used solely clustering-based approaches, and four studies used a combination of both. Co-occurrence methods include additive index-based approaches and presenting specific health combinations, and whilst simple to construct and interpret, do not consider the underlying associations between co-occurring behaviors/risk factors. Clustering-based approaches do focus on underlying associations, and further work in this area may aid in identifying at-risk subgroups and understanding specific combinations of health-related behaviors/risk factors of particular importance in the scope of cognitive function and neurocognitive decline.

CONCLUSION

A co-occurrence approach to aggregating health-related behaviors/risk factors and exploring associations with adult cognitive outcomes has been the predominant statistic approach used to date, with a lack of research employing more advanced statistical methods to explore clustering-based approaches.

Caregiver Perceptions of Children's and Adolescents' Psychosocial Functioning During the Stringent COVID-19 Lockdown Restrictions in Shanghai: Cross-sectional Study

BACKGROUND

The COVID-19 pandemic represents a global health crisis. The Shanghai municipal government in China implemented strict and comprehensive pandemic control strategies in the first half of 2022 to eliminate a wave of COVID-19 infection. The pandemic and the resulting government responses have led to abrupt changes to families' daily lives, including the mental health of children and adolescents.

OBJECTIVE

The aim of this paper is to examine the impact of COVID-19 exposure and the stringent lockdown measures on the daily life and mental health of children and adolescents and to provide suggestions on maintaining their mental health when similar public health emergencies occur in the future.

METHODS

In this cross-sectional study, an anonymous survey was distributed online in May 1-15, 2022, in Shanghai. Individuals were eligible to participate if they were currently the caregiver of a child or adolescent (aged 4-17 years). Outcomes were psychosocial functioning of children and adolescents, as reported by parents, using the Pediatric Symptom Checklist-17. COVID-19 exposure and life changes were also reported. Multivariate logistic regression was used to analyze risk factors for poor psychosocial functioning.

RESULTS

In total, 2493 valid questionnaires were analyzed. The rate of positive scores on the global Pediatric Symptom Checklist-17 scale was 16.5% (n=411). Internalizing, attention, and externalizing problem subscale positivity rates were 17.3% (n=431), 10.9% (n=272), and 8.9% (n=221), respectively. Caregivers reported that 64.2% (n=1601) and 20.7% (n=516) of the children's interactions with friends or peers and parents deteriorated, respectively. Compared with male caregivers, female caregivers were less likely to report psychosocial problems in children and adolescents (adjusted odds ratio [aOR] 0.68; 95% CI 0.53-0.88). Older children and those with lower COVID-19 Exposure and Family Impact Scales scores were less likely to have psychological problems (aOR 1.15; 95% CI 1.10-1.21). Compared with children with screen times <1 hour per day for recreation, those using screens for >3 hours had higher odds of psychological distress (aOR 2.09; 95% CI 1.47-1.97). Children who spent 1-2 hours exercising and had better interactions with friends or peers and parents showed a trend toward lower odds of psychological problems. Children and adolescents with worse sleep compared with preclosure were more likely to have psychological problems.

CONCLUSIONS

The prevalence of psychosocial problems among children and adolescents is relatively high. Being young, having more COVID-19 exposure, and having more screen times (>3 h/day), less exercise time (<30 min), worse sleep, and deteriorated interactions with friends or peers and parents were risk factors for poor psychosocial functioning. It is necessary for governments, communities, schools, and families to take appropriate countermeasures to reduce the negative impact of the stringent control measures on caregivers' parenting and psychosocial functioning of children and adolescents.

Excessive Sedentary Time Is Associated with Cognitive Decline in Older Patients with Minor Ischemic Stroke

BACKGROUND

Cognitive impairment is commonly seen after acute ischemic stroke (AIS). Sedentary behaviors increase the risk of dementia among community dwelling population.

OBJECTIVE

This study aims to investigate the association of sedentary behaviors with poststroke cognitive impairment among older adults with minor AIS.

METHODS

This cohort study recruited 594 older subjects with minor AIS from three hospitals in China during February 1, 2016, and December 31, 2018. Participants were followed up for two years and the sedentary time per day was self-reported at the end of follow-up. Cognitive functions were assessed by Mini-Mental State Examination (MMSE). Participants were categorized into the high and low sedentary time group according to the median sedentary time of the participants.

RESULTS

At two years of follow-up, the long sedentary time group had significantly lower MMSE scores than the short sedentary time group [median, (IQR): 21 (18 to 25) versus 22 (18 to 25), p = 0.368]. The long sedentary time group had a higher speed of cognitive decline than the short sedentary time group. Excessive sedentary time was associated with a higher risk of longitudinal cognitive decline (OR: 2.267, 95% CI: 1.594 to 3.225), adjusting for age, sex, education, body mass index, APOE genotype, comorbidities, symptoms of depression, anxiety, and insomnia, baseline MMSE scores and National Institute of Health Stroke Scale scores, cognitive therapy, and TOAST ischemic stroke subtypes.

CONCLUSIONS

This study identified a possible link between sedentary behaviors and longitudinal cognitive decline among older patients with minor AIS, suggesting that reducing sedentary time might be helpful for preventing poststroke dementia.

Demand Coupling Drives Neurodegeneration: A Model of Age-Related Cognitive Decline and Dementia

The societal burden of Alzheimer's Disease (AD) and other major forms of dementia continues to grow, and multiple pharmacological agents directed towards modifying the pathological "hallmarks" of AD have yielded disappointing results. Though efforts continue towards broadening and deepening our knowledge and understanding of the mechanistic and neuropathological underpinnings of AD, our previous failures motivate a re-examination of how we conceptualize AD pathology and progression. In addition to not yielding effective treatments, the phenotypically heterogeneous biological processes that have been the primary area of focus to date have not been adequately shown to be necessary or sufficient to explain the risk and progression of AD. On the other hand, a growing body of evidence indicates that lifestyle and environment represent the ultimate level of causation for AD and age-related cognitive decline. Specifically, the decline in cognitive demands over the lifespan plays a central role in driving the structural and functional deteriorations of the brain. In the absence of adequate cognitive stimulus, physiological demand-function coupling leads to downregulation of growth, repair, and homeostatic processes, resulting in deteriorating brain tissue health, function, and capacity. In this setting, the heterogeneity of associated neuropathological tissue hallmarks then occurs as a consequence of an individual's genetic and environmental background and are best considered downstream markers of the disease process rather than specific targets for direct intervention. In this manuscript we outline the evidence for a demand-driven model of age-related cognitive decline and dementia and why it mandates a holistic approach to dementia treatment and prevention that incorporates the primary upstream role of cognitive demand.