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

Associations between sleep quality, plasma neurofilament light, and cognition in older adults without dementia

The relationship between sleep quality, neurofilament light chain (NFL), and cognitive impairment, including the potential effect of plasma NFL in this association, remains unclear. Using the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, we excluded individuals with dementia or a history of sleep-related medication use at baseline, including 640 participants with complete sleep assessments and covariates. Sleep quality was assessed using the Neuropsychiatric Inventory sleep subscale, which includes ratings of frequency, severity, and their product, with higher scores indicating poorer sleep quality. Baseline and follow-up demographics, sleep indices, plasma NFL levels, and cognition scores (including Mini-Mental State Examination [MMSE], Montreal Cognitive Assessment [MoCA], Alzheimer's Disease Assessment Scale-Cognitive Subscale [ADAS13], Clinical Dementia Rating Scale-Sum of Boxes [CDRSB], Executive Function [EF], Language [LAN], and Memory [MEM]) were also collected. Multivariable linear regression examined the associations between baseline sleep quality, plasma NFL, and cognition, as well as the relationship between sleep quality and longitudinal cognitive decline, calculated using linear mixed-effects models. Mediation analysis evaluated the role of plasma NFL in the sleep-cognition association. Multiple testing significance was corrected using false discovery rate, with results presented as Q-values. Poor sleep quality scores were associated with elevated plasma NFL levels (β: 0.055 to 2.645, P < 0.05), poorer cognition (ADAS13, CDRSB, EF, LAN, MEM; β: -0.188 to 1.279, Q < 0.05), and accelerated longitudinal cognitive decline (MoCA; β: -0.005, Q < 0.05) in both models, with sensitivity analyses supporting these findings. Furthermore, plasma NFL levels partially mediated the relationship between sleep quality and both baseline cognition (ADAS13, CDRSB, LAN, MEM; P < 0.05) and longitudinal cognitive decline (MoCA; P < 0.05), with mediation proportions ranging from 9.2% to 26.7%. Poorer sleep quality was associated with cognitive impairment and accelerated cognitive decline, suggesting its potential role in Alzheimer's disease. These associations may be partially mediated by neuroaxonal injury.

Urban heat island impacts on mental health in middle-aged and older adults

BACKGROUND

Urban heat island (UHI), attributed to rapid urbanization, might be a latent modifiable risk factor for human health, yet little is known about whether UHI puts a strain on public mental health. This study aimed to assess the effect of the summer UHI on mental health.

METHODS

Leveraging 338,363 urban residents from the UK Biobank, this study estimated the associations of summer UHI effect with incidence risks of mental disorders, substance use disorder, depressive disorder, and anxiety disorder using both time-independent and time-dependent Cox regression models with full adjustment for possible confounders. Furthermore, the effect of UHI on related psychiatric symptoms and brain microstructure were explored through logistic regression models and multiple linear regression models, respectively.

RESULTS

In this study, summer UHI was significantly associated with the elevated risks of psychiatric disorders. The hazard ratio with a 95% confidence interval (CI) from the time-dependent Cox model was 1.04 (95% CI, 1.03-1.05) for mental disorders, 1.12 (1.11-1.14) for substance use disorder, 1.08 (1.06-1.10) for depressive disorder, and 1.06 (1.04-1.08) for anxiety disorder per standard deviation of UHI intensity, respectively. Subgroup analyses showed that females and individuals with hypertension or coronary artery disease were more vulnerable to the UHI effect on mental health. The detrimental effects on psychiatric symptoms and white matter microstructure were also observed.

CONCLUSION

The study suggested UHI could be an environmental stressor and induce a heavier burden on mental health. The effective mitigation of urban heat stress could benefit both public health and sustainable development.

Associations of physical activity, sedentary behavior, and sleep with risk of incident Parkinson's disease: A prospective cohort study of 401,697 participants

BACKGROUND

Physical activity, sedentary behavior (SB), and sleep duration are associated with brain health. Effects of those on developing Parkinson's disease (PD) are poorly investigated. This study aimed to examine the independent and joint associations of physical activity, SB, sleep with PD risk.

METHODS

We analyzed data on 401,697 participants from the UK Biobank cohort, which was enrolled in 2006-2010. Physical activities were measured based on a questionnaire. Sleep and SB time were defined through self-reported total number of hours. Models fitted with restricted cubic spline were conducted to test for linear and non-linear shapes of each association. Cox proportional hazards regression models were used to estimate the association of three modifiable behaviors.

RESULTS

Our analytic sample included 401,697 participants with 3030 identified cases of PD (mean age, 63 years; 62.9% male). PD risk was 18% lower in the high total physical activity group (95% CI, 0.75-0.90), 22% lower in the high leisure-time physical activity (LTPA) group (95% CI, 0.71-0.86) compared with the low level and 14% higher in the high sleep duration group (95% CI, 1.05-1.24) compared to moderate group. Total SB time was irrelevant with PD risk, while high TV viewing showed a 12% increase of PD risk compared to the low group (95% CI, 1.02-1.22). Low computer use (0 h/day) was associated with a 14% higher risk compared to 1 h/day use (95% CI, 1.04-1.26). Those associations were independent. A combination of 7 h/day sleep, moderate-to-high computer use, and moderate-to-vigorous intensity of LTPA showed lowest PD risk (HR, 0.70; 95% CI, 0.57-0.85).

CONCLUSIONS

Physical activity, SB, and sleep were associated with PD risks separately. Our findings emphasize the possibility for changing these three daily activities concurrently to lower the risk of PD. These findings may promote an active lifestyle for PD prevention.

Accelerometer-derived "weekend warrior" physical activity, sedentary behavior, and risk of dementia

BACKGROUND

Research has shown that sedentary behavior (SB) may increase dementia risk, but it remains unclear whether concentrated moderate to vigorous physical activity (MVPA) can compensate such negative effects. This study aimed to explore the association between different MVPA patterns combined with SB time and the risk of dementia.

METHODS

This prospective study used data from the UK Biobank cohort, which provided accelerometer-based physical activity data for a full week from February 2013 to December 2015. Participants were categorized into "weekend warriors (WW)" group, engaged in more than 50% MVPA (≥ 150 min/week) on 1 to 2 days; inactive group (total MVPA < 150 min/week); and regular group, who met the recommended MVPA (≥ 150 min/week) but not WW. The participants were further divided into six groups based on SB duration (≥ 8.52 h/day or < 8.52 h/day). A multivariable Cox model was used to assess the relationship between these patterns and the risk of dementia, adjusted by age, gender, ethnicity, Townsend deprivation index, education level, employment status, alcohol consumption, smoking, BMI, and baseline comorbidities (including cardiovascular disease, hypertension, and diabetes).

RESULTS

We included 91,948 participants without dementia at baseline. During a median follow-up of 7.93 years, 736 participants developed all-cause dementia. When the MVPA threshold was set at 150 min per week, 16,149 participants (17.5%) were classified as WW with long SB, 19,055 (20.7%) as regular with long SB, and 21,909 (23.8%) as inactive with long SB. Compared to inactive and long SB time, the WW group showed a reduction in dementia risk (WW with long SB time: HR = 0.69, 95% CI: 0.54-0.87, P = 0.002; WW with short SB time: HR = 0.74, 95% CI: 0.56-0.97, P = 0.029). And regular group with shorter SB time was associated with a lower dementia risk (HR = 0.75, 95% CI: 0.59-0.96, P = 0.021), but not in the group with longer SB time.

CONCLUSIONS

The WW pattern may help mitigate the dementia risk associated with prolonged SB, suggesting that the quality and intensity of physical activity are also important factors.

Physical Activity, Sleep, and Risk of Late-Onset Severe Mental Illness: A Prospective Cohort Study From UK Biobank

BACKGROUND AND HYPOTHESIS

Previous studies have found that both physical inactivity and poor sleep are deleteriously associated with severe mental illness (SMI). The aim of current study was to investigate the joint association of physical activity (PA) and sleep with late-onset SMI (schizophrenia and bipolar disorder) risk.

STUDY DESIGN

A total of 340 187 (for schizophrenia)/340 239 (for bipolar disorder) participants without schizophrenia or bipolar disorder from the UK Biobank were included. Baseline PA levels were categorized as high, intermediate, and low according to the total volume of PA. Sleep was categorized into healthy, intermediate, and poor according to an established composited sleep score of chronotype, sleep duration, insomnia, snoring, and daytime sleepiness. We derived 9 PA-sleep combinations, accordingly.

STUDY RESULTS

After an average follow-up of 13.2 years, 814 participants experienced schizophrenia and 846 participants experienced bipolar disorder. Both low PA level, intermediate, and poor sleep were independently associated with increased risk of SMI. PA level and sleep had additive and multiplicative interactions on SMI risk. Compared to those with high PA level and healthy sleep, individuals with low PA and poor sleep had the highest risk of SMI (hazard ratio: 1.95; 95% CI: 1.02-3.70, P < .001) for schizophrenia; (hazard ratio: 3.81; 95% CI: 2.35-6.15) for bipolar disorder. A higher PA level may attenuate the detrimental effects of poor sleep.

CONCLUSION

Both low PA and poor sleep was associated with increasing risk of late-onset SMI. Those with low PA and poor sleep had the highest risk of late-onset SMI, suggesting likely synergistic effects. Our findings supported the need to target both PA and sleep behaviors in research and clinical practice.

Community-based going-out program and dementia onset in Japanese older adults: A longitudinal observational study

OBJECTIVES

With dementia prevalence rising globally among older adults, effective and scalable community-based interventions are urgently needed to reduce dementia onset. This study aimed to estimate the association of the going-out program with dementia onset in older adults.

METHODS

A 5-year longitudinal observational study was employed. Following a baseline assessment in 2015 and 2017, we observed 2,977 individuals engaging in a community-based going-out program for 12 months in Japan. Participants with continuous data over 12 months were defined as the engaged group, while those without such data were classified as the non-engaged group. After propensity score matching, 1,690 participants were selected. Dementia onset was obtained from the Japanese National Health Insurance and Later-Stage Medical Care System for 48-month follow-up. Incidence of dementia, absolute risk reduction (ARR), and number needed to treat (NNT) were calculated. The Cox proportional hazards model was used to estimate the effect of engagement in the program on dementia onset and to calculate a hazard ratio and 95 % confidential interval (CI).

RESULTS

The incidence of dementia onset was 59 out of 845 (7.0 %) in the non-engagement group and 34 out of 845 (4.0 %) in the engagement group. The ARR rate was 3.0 % (95 % CI 0.8, 5.2), and the NNT was 33 (95 % CI 19, 125). The hazard ratio was 0.57 (95 % CI 0.37, 0.86).

DISCUSSION

Engagement in the going-out program resulted in a 3.0 % reduction in the risk of dementia onset. The going-out program, which can be implemented in communities, holds potential efficacy in preventing dementia onset.

Television viewing, oxidative stress, and kidney stone risk in males: a cross-sectional study with mediation analysis of the NHANES data (2011-2018 years)

PURPOSE

To explore the association between television viewing time (TV-hours) and dietary oxidative balance score (DOBS) with the kidney stone risk in males.

METHODS

We analyzed age, poverty to income ratio, race, education, hypertension, diabetes, smoke, alcohol use, triglycerides, TV-hours, and DOBS data in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. Multivariable logistic regression was uesd to evaluate the associations between TV-hours, lifestyle OBS (LOBS), DOBS, Total OBS (TOBS), and the risk of kidney stones. Interaction terms between subgroup measures were used to test for effect modification across subgroups. Mediation analysis was performed to explore the mediating effect of DOBS on the association between TV-hours and kidney stones. The restricted cubic spline (RCS) was applied to describe dose-response relationships between TV-hours and risk of kidney stones as well.

RESULTS

The study included 4167 males aged 20 and older, including 417 patients with kidney stones. The results showed that five or more TV-hours a day was associated with a higher risk of kidney stones [odds ratio (OR) = 1.16, (95% CI: 1.04-1.29), p = 0.01], and higher DOBS level was associated with a lower risk of kidney stones [OR = 0.97, (95% CI: 0.95-0.99), p = 0.004]. This association was remarkably consistent across TV-hours subgroups by age, race, alcohol use, hypertension and diabetes. According to the mediation analysis results, prolonged TV-hours is associated with an increased risk of kidney stones, this association is not mediated by DOBS. In other words, the impact of TV-hours on kidney stones risk is mainly a direct effect. When TV-hours is more than 2 hours, the odds ratio began to be greater than 1.

CONCLUSIONS

Overall, TV-hours was positively associated with kidney stones in males, whereas low DOBS was associated with kidney stones in males. This study suggests that an antioxidant diet and reduced television viewing time may be effective measures to prevent kidney stones in males.

Independent associations of sleep and physical activity with cognition are mediated by hippocampal microstructure in middle-aged and older adults

Sleep and physical activity levels are both associated with cognitive performance among older adults; however, the brain mechanisms underlying these beneficial relationships remain poorly understood. This study investigated cross-sectional associations of actigraphic estimates of physical activity and sleep with cognition and diffusion imaging-based measures of medial temporal lobe (MTL) gray matter microstructural integrity in adults free of dementia. Participants were 132 older adults from the Biomarkers of Cognitive Decline Among Normal Individuals (BIOCARD) cohort study (119 cognitively unimpaired and 13 with mild cognitive impairment; mean age=70.8 years). Multiple linear regression analyses assessed the relationships between total volume of physical activity (TVPA), total sleep time (TST), and sleep efficiency (SE) with cognitive performance and MTL microstructural integrity. Results indicated that greater TVPA and SE were both independently associated with higher hippocampal and parahippocampal microstructure integrity (indicated by lower mean diffusivity) and better visuospatial processing abilities, independent of the volume of these structures and of amyloid burden, measured by positron emission tomography. Additionally, higher hippocampal microstructure statistically mediated the independent associations of physical activity and sleep with visuospatial abilities, independent of MTL volume and Aβ load. These findings suggest that physical activity and sleep are independently associated with cognitive performance, and that hippocampal microstructural integrity may be an underlying mechanism supporting these associations.

Dose-response associations of device-measured sleep regularity and duration with incident dementia in 82391 UK adults

BACKGROUND

Sleep is a crucial lifestyle factor with impacts on mental and cognitive health. The associations between objectively measured sleep and risk of incident dementia are not yet fully understood. To evaluate the associations of device-measured sleep duration and regularity with incident dementia and explore whether sleep regularity moderates the association of sleep duration with dementia.

METHODS

Population-based prospective cohort study of 82,391 adults aged 43 to 79 years from the UK Biobank accelerometry subsample, collected between 2013 and 2015, followed up to 2022. Device-based sleep duration (h/day) and sleep regularity index (SRI), a metric ranging from 0-100 that quantifies a person's sleep regularity (with a greater value indicating higher consistency), were calculated from wrist-worn accelerometry data recorded over the course of one week. Incident all-cause dementia cases were obtained from national hospital admission, primary care and mortality data followed up to 30 November 2022. We used Cox proportional hazard models to estimate the hazard ratios (HRs) for incident dementia after adjustment for common demographic and clinical covariates.

RESULTS

Over a mean follow-up of 7.9 years, 694 incident dementia cases occurred. We observed a U-shaped association between sleep duration and incident dementia, with only short sleep (< 7 h) being significantly associated with a higher risk of dementia. The median sleep duration for short sleepers (< 7 h) of 6.5 h, compared to the reference point of 7.9 h was associated with HR of 1.19 (95%CI 1.01,1.40) for incident dementia. Sleep regularity was negatively associated with dementia risk in a near-linear fashion (linear p = 0.01, non-linear p = 0.57). When we dichotomized sleep regularity, those in the higher sleep regularity group (SRI ≥ 70) had an HR of 0.74 (95%CI 0.63, 0.87) compared to those with lower sleep regularity (SRI < 70). The beneficial associations between sleep regularity and incident dementia were present only among participants with short (< 7 h) and long (≥ 8 h) sleep duration.

CONCLUSIONS

Assuming that the associations we observed are causal, maintaining a regular sleep pattern may help offset the deleterious association of inadequate sleep duration with dementia. Interventions aimed at improving sleep regularity may be a viable option for people not able to achieve the recommended hours of sleep.

Sleep Patterns and Human Brain Health

It is a widely held opinion that sleep is important for human brain health. Here we examine the evidence for this view, focusing on normal variations in sleep patterns. We discuss the functions of sleep and highlight the paradoxical implications of theories seeing sleep as an adaptive capacity versus the theory that sleep benefits clearance of metabolic waste from the brain. We also evaluate the proposition that sleep plays an active role in consolidation of memories. Finally, we review research on possible effects of chronic sleep deprivation on brain health. We find that the evidence for a causal role of sleep in human brain health is surprisingly weak relative to the amount of attention to sleep in science and society. While there are well-established associations between sleep parameters and aspects of brain health, results are generally not consistent across studies and measures, and it is not clear to what extent alterations in sleep patterns represent symptoms or causes. Especially, the proposition that long sleep (>8 hours) in general is beneficial for long-term brain health in humans seems to lack empirical support. We suggest directions for future research to establish a solid foundation of knowledge about a role of sleep in brain health based on longitudinal studies with frequent sampling, attention to individual differences, and more ecologically valid intervention studies.

Smoking cessation is a protective factor for lung cancer onset and mortality: a population-based prospective cohort study

BACKGROUND

Smoking is a pivotal modifiable risk factor for lung cancer (LC). Previous studies have indicated that a smoking cessation program might be incorporated into the LC screening program. However, the effects of smoking cessation and its duration with the age at onset (AAO) of LC, all-cause mortality, and LC-specific mortality remain unclear. We aimed to comprehensively investigate the association of smoking cessation-related behaviors on the AAO of LC, LC-specific and all-cause mortality.

METHODS

A total of 2671 smokers with LC as the primary site from the UK Biobank were included in this study, with a 7:3 ratio assigned randomly to a discovery set (n = 1872) and a validation set (n = 799). Generalized linear regression models were used for AAO of LC outcomes and Cox models for mortality outcomes.

RESULTS

Participants over 60 years old could still benefit from smoking cessation to prolong AAOs (β = 1.613 for men, P = 0.003; β = 1.533 for women, P = 0.018). A cessation duration of > 15 years was associated with a later AAO in men (P < 0.001). Moreover, smoking cessation before 60 years old, especially among those under 40 years, was significantly associated with a lower risk of all-cause mortality (men: hazard ratio (HR): 0.65 [95% confidence interval 0.51-0.83]; women: 0.62 [0.47-0.83]) and LC-specific mortality (men: 0.67 [0.51-0.87]; women: 0.68 [0.50-0.92]). Compared with continuous smokers, former smokers who quit smoking for more than 15 years had a lower risk of all-cause mortality (men: 0.70 [0.59-0.84]; women: 0.68 [0.56-0.84]) and LC-specific mortality (men: 0.71 [0.59-0.87]; women: 0.69 [0.56-0.86]).

CONCLUSIONS

Smoking cessation after 60 years old may still be helpful for a later AAO of LC. Former smokers who quit smoking for more than 15 years have a reduced risk of developing LC and mortality.

Daily-life walking speed, running duration and bedtime from wrist-worn sensors predict incident dementia: A watch walk - UK biobank study

OBJECTIVE

To determine if wrist-worn sensor parameters can predict incident dementia in individuals aged 60 + years and to compare prediction with other tools.

DESIGN

Observational cohort study.

SETTING

Community PARTICIPANTS: The cohort comprised 47,371 participants without dementia, aged 60 + years, who participated in the UK Biobank study (mean age=67 ± 4 years; 52 % female).

MEASUREMENTS

Nineteen digital biomarkers were extracted from up-to-7-day wrist-worn sensor accelerometry data at baseline. Univariable and multivariable Cox proportional hazard models examined associations between sensor parameters and prospectively diagnosed dementia.

RESULTS

Median follow-up was 7.5 years (interquartile range: 7.0 to 9.0 years), during this time 387 participants (0.8 %) were diagnosed with dementia. Among the gait parameters, slower maximal walking speed had the strongest association with incident dementia (32 % decrease in hazard for each standard deviation increase) followed by lower daily step counts (30 % decrease) and increased step-time variability (17 % increase). While adjusting for age and sex, running duration, maximal walking speed and early bedtime were identified as independent and significant predictors of dementia. The multivariable prediction model performed comparably to the ANU-ADRI and UKB-Dementia Risk Score models in the UK Biobank cohort.

CONCLUSIONS

The study findings indicate that remotely acquired parameters from wrist-worn sensors can predict incident dementia. Since wrist-worn sensors are highly acceptable for long-term use, wrist-worn sensor parameters have the potential to be incorporated into dementia screening programs.

Socioeconomic Inequalities in Dementia Risk Among a Population-Based Cohort: Quantifying the Role of a Broad Combination of Lifestyle Factors

OBJECTIVES

The complex associations of socioeconomic status (SES) and lifestyle with dementia are unclear. Our objective was to examine whether a broad combination of lifestyle factors mediates the associations of SES with incident dementia and the extent of interaction or joint relations of lifestyles and SES with dementia.

METHODS

A total of 274,871 participants from the UK Biobank were included. SES was assessed using the Townsend Deprivation Index. A lifestyle index was created based on smoking status, alcohol consumption, physical activity, social connections, sleep duration, diet, and sedentary behavior. Cox proportional hazards models were fitted. Mediation and interaction analyses were conducted to explore the relationship between lifestyles and SES in dementia.

RESULTS

The hazard ratios (HRs) and 95% confidence intervals (CIs) for when participants with low SES were compared with participants with high SES were 1.32 (1.22-1.42) for all-cause dementia, 1.25 (1.11-1.40) for Alzheimer's disease (AD), and 1.61 (1.37-1.90) for vascular dementia (VD). Lifestyles explained ≤7.8% of socioeconomic disparities in dementia. Unhealthy lifestyle categories were associated with a higher risk of dementia and its subtypes across all SES levels. The HRs (95% CIs) for all-cause dementia, AD, and VD comparing participants with low SES and the least healthy lifestyle versus those with high SES and the healthiest lifestyle were 1.82 (1.56-2.11), 1.51 (1.20-1.90), and 2.56 (1.81-3.61), respectively.

DISCUSSION

Adhering to a healthy lifestyle may prevent dementia across all socioeconomic groups, but socioeconomic inequalities in dementia cannot be fully addressed by promoting healthy lifestyles alone. The social determinants of dementia need to be better addressed.

The effects of sleep duration on the risk of dementia incidence in short and long follow-up studies: A systematic review and meta-analysis

Sleep duration's association with future dementia could be a cause or consequence, or both. We searched electronic databases on 14th April 2023 for primary peer-reviewed, longitudinal studies examining the relationship between sleep duration and dementia with any follow-up duration. We meta-analysed studies examining brief (≤6 h/night) and extended sleep duration (≥9 h/night) separately and divided the studies into those with follow-up periods of less or more than 10 years. The quality of evidence was assessed using the Newcastle-Ottawa scale. 31 studies fulfilled the inclusion criteria. For brief sleep duration, a meta-analysis of short follow-up studies (≤10 years) found a 46 % increased risk of future dementia (relative risk [RR] - 1·46; 95 % Confidence Intervals [CIs] 1·48-1·77; I2 = 88·92 %, 6 studies). Studies with long follow-ups (>10 years) did not show a significantly increased risk (RR - 1·12; 0·95-1·29; I2 = 65·91 %; 5 studies). For extended sleep duration, a meta-analysis of short and long follow-up studies reported an increased risk of dementia (respectively RR - 2·20; 1·11-3·3; I2 = 94·17 %; 4 studies and RR - 1·74; 1·30-2·18; I2 = 86·56 %; 4 studies). Our findings suggest that brief sleep duration might be a prodromal symptom but not a risk factor of dementia. Extended sleep duration may be a risk factor. However, our results had high heterogeneity limiting external validity and generalisability.

Brain function assessment of acupuncture for chronic insomnia disorder with mild cognitive dysfunction based on fNIRS: protocol for a randomized controlled trial

Background

Chronic Insomnia Disorder (CID) is highly prevalent among older adults and impairs cognitive function. Insomnia accelerates the progression of mild cognitive impairment (MCI) and increases the risk of developing dementia. Acupuncture has been demonstrated in improving sleep quality and cognitive function. This study aims to explore the functional brain characteristics of CID with MCI patients and to assess the effects of acupuncture therapy using functional near-infrared spectroscopy (fNIRS).

Methods and design

This study is a single-center randomized controlled trial. Participants will be randomly assigned to the manual acupuncture group or the placebo acupuncture group for an 8-week intervention period. fNIRS data will be collected during resting test and working memory test at baseline and at end of the intervention. The primary outcome is the change of the Montreal Cognitive Assessment (MoCA) score, secondary outcomes include the change of Mini-Mental State Examination (MMSE), Insomnia Severity Index (ISI), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder Scale (GAD-7), and Apathy Evaluation Scale-Informant (AES-I).

Discussion

The results of the study will provide insights into the effects of acupuncture on sleep quality and cognitive performance in CID with MCI patients. By utilizing fNIRS technology, we will elucidate the neural functional characteristic underlying the therapeutic benefits of acupuncture.

Clinical trial registration

https://ClinicalTrials.gov, identifier ChiCTR2300076182.

Independent and joint role of inflammatory diet and physical activity with cognitive function in aging: Evidence from a population-based survey

OBJECTIVE

This study aims to explore the independent and joint association of physical activity (PA) and inflammatory diet with cognitive function in aging.

METHOD

Data from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) was used. 2249 NHANES participants with valid data represented a weighted population of 50.5 million American residents aged 60 and older. This study separately analyzed the independent associations of PA (measured by global physical activity questionnaire) and inflammatory diet (measured by energy-adjusted dietary inflammatory index from 24-h dietary recall), and their joints (inactive & pro-inflammatory as reference) with cognitive function (assessed by three cognitive tests), and considered an individual of different status and non-linear effect by sub-group and restricted cubic splines (RCS) analysis, respectively. All analysis was multivariable-adjusted and sample-weighted.

RESULTS

The results showed that inflammatory diet was independently associated with lower cognitive function, with a 1.08, 1.29, 2.67, 0.56 lower score in the Registry for Alzheimer's Disease word list learning test (CERAD), the Animal Fluency Test (AFT), the Digit Symbol Substitution test (DSST), Z-scores, and 51 %, 62 %, 63 %, 93 % higher odds ratio (OR) of lower performance in CERAD, AFT, DSST, and p-MCI, respectively. PA was independently associated with higher cognitive function, with a 1.41, 3.37, and 0.52 higher score in AFT, DSST, Z-scores, and 28 %, 51 %, 41 % lower ORs of lower performance in CERAD and DSST and p-MCI, respectively. Active & Anti-inflammatory was always positively associated with cognitive function, with a 1.42, 2.69, 5.47, and 1.04 higher score for CERAD, AFT, DSST, and Z-score, a 58 %, 56 %, 74 %, 76 % lower ORs of lower performance in CERAT, AFT, DSST, and p-MCI, respectively, which elicited the maximum compared to other joints.

CONCLUSION

Adhering to both active PA and anti-inflammatory diet is recommended for cognitive management in older adults. Sticking to either active PA or anti-inflammatory diet also shows potential cognitive benefits, with the diet possibly playing more vital role.

Sleep disturbances and intrinsic capacity trajectories among Chinese older adults: The Rugao Longevity and Ageing Study

Age related decline of intrinsic capacity (IC) is the core of the functional ability and risk factor of adverse outcomes such as disability, hospitalization, and mortality. However, the relationship between sleep disturbance and IC decline are largely unknown. We conducted a longitudinal study and used data of 1514 community elders from the aging arm of the Rugao Longevity and Ageing Study. We found that poor sleep quality is cross-sectional associated with an increased risk of lower IC. In longitudinal analysis, sleep disturbances were inversely associated with composite IC score changes after adjusting for confounders (PSQI>5 vs. PSQI≤5: mean difference [-0.23], P = 0.0005), suggesting that poor sleep quality was associated with a decline in IC during the follow-up period. In conclusion, sleep disturbances were associated with worse IC changes. The results suggest that improving sleep health may help prevent IC decline and hence decreasing the burden of geriatric nursing practice.

Assessment of sleep patterns in dementia and general population cohorts using passive in-home monitoring technologies

BACKGROUND

Nocturnal disturbances are a common symptom experienced by People Living with Dementia (PLWD), and these often present prior to diagnosis. Whilst sleep anomalies have been frequently reported, most studies have been conducted in lab environments, which are expensive, invasive and not natural sleeping environments. In this study, we investigate the use of in-home nocturnal monitoring technologies, which enable passive data collection, at low cost, in real-world environments, and without requiring a change in routine.

METHODS

Clustering analysis of passively collected sleep data in the natural sleep environment can help identify distinct sub-groups based on sleep patterns. The analysis uses sleep activity data from; (1) the Minder study, collecting in-home data from PLWD and (2) a general population dataset (combined n = 100, >9500 person-nights).

RESULTS

Unsupervised clustering and profiling analysis identifies three distinct clusters. One cluster is predominantly PLWD relative to the two other groups (72% ± 3.22, p = 6.4 × 10-7, p = 1.2 × 10-2) and has the highest mean age (77.96 ± 0.93, p = 6.8 × 10-4 and p = 6.4 × 10-7). This cluster is defined by increases in light and wake after sleep onset (p = 1.5 × 10-22, p = 1.4 × 10-7 and p = 1.7 × 10-22, p = 1.4 × 10-23) and decreases in rapid eye movement (p = 5.5 × 10-12, p = 5.9 × 10-7) and non-rapid eye movement sleep duration (p = 1.7 × 10-4, p = 3.8 × 10-11), in comparison to the general population.

CONCLUSIONS

In line with current clinical knowledge, these results suggest detectable dementia sleep phenotypes, highlighting the potential for using passive digital technologies in PLWD, and for  detecting architectural sleep changes more generally. This study indicates the feasibility of leveraging passive in-home technologies for disease monitoring.

Sleep patterns, physical activity, genetic susceptibility, and incident rheumatoid arthritis: a prospective cohort study

BACKGROUND

Sleep and physical activity (PA) are thought to be interconnected with the development of rheumatoid arthritis (RA). However, the precise nature and extent of these relationships have yet to be fully quantified. This study aimed to quantify the longitudinal effects of sleep behaviors, PA, and genetic susceptibility on the incidence of RA and to estimate the combined effects and interactions among these exposures.

METHODS

A total of 363,211 adults were derived from a large European cohort. We incorporated five sleep behaviors (sleep duration, insomnia, snoring, chronotype, and daytime sleepiness) to generate sleep patterns, which were defined based on healthy sleep scores. Multivariate-adjusted Cox proportional hazard models were conducted to assess the individual and combined associations of sleep patterns, PA, and genetic susceptibility with the risk of RA occurrence. Multiplicative and additive interactions were estimated by Pinteraction and relative excess risk due to interaction (RERI) between each of the two exposures.

RESULTS

During a follow-up of 12.5 years, 4262 RA cases were ascertained. A healthy sleep pattern was associated with a decreased risk of RA in a dose-response manner, with an adjusted hazard ratio (HR) of 0.79 (95% confidence interval [CI] = 0.75-0.84), independent of traditional risk factors and genetic predisposition. Under the restricted cubic splines model, a non-linear association was detected for PA and RA risk. Participants in the intermediate quintile 3 showed the lowest risk for developing RA, with a HR 95% CI of 0.84 (0.76-0.92). Moreover, there was an additive interaction effect of intermediate sleep pattern and PA, with a 0.45 (95% CI = 0.02-0.87) RERI of developing RA. Additionally, individuals at high genetic risk had the greatest 10-year absolute risk reduction (10.58 per 1000 person-years) when adopting both favorable behaviors.

CONCLUSIONS

A healthy sleep pattern and moderate PA were associated with a reduced risk of developing RA, which can offset the deleterious effects of predisposing genetic components. Implementing these modifiable lifestyle factors into public health practices is beneficial for RA prevention.

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.

Leisure Sedentary Behavior, Physical Activities, and Cardiovascular Disease Among Individuals With Metabolic Dysfunction-Associated Fatty Liver Disease

BACKGROUND

Metabolic dysfunction-associated fatty liver disease is a significant risk factor for cardiovascular disease (CVD). This study assesses the association between leisure-time physical activity, sedentary behavior, and CVD risk among patients with metabolic dysfunction-associated fatty liver disease, considering genetic predisposition to CVD.

METHODS

This cohort study included 157 794 participants with metabolic dysfunction-associated fatty liver disease from the UK Biobank who were free of CVD at baseline. The study measured leisure-time sedentary behaviors (watching TV, using a computer, and driving) and physical activities (walking for pleasure, light and heavy do-it-yourself activities, strenuous sports, and other exercises) in terms of frequency and duration over the 4 weeks before assessment. Both a Cox proportional hazard model and an isotemporal substitution model were utilized in the study to assess the association between leisure sedentary behavior, physical activities, and CVD risk.

RESULTS

During a median 12.5 years of follow-up, 26 355 CVD cases were reported, including 19 746 coronary heart disease, 4836 stroke, and 7398 heart failure cases. High physical activity levels were linked to a significantly lower risk of CVD (21%), coronary heart disease (20%), stroke (15%), and heart failure (31%). In contrast, individuals with >6.5 h/d of sedentary behavior faced a 16% to 21% higher risk of these conditions compared with those with ≤3.5 h/d. Notably, replacing 30 minutes of inactivity with physical activity reduced CVD risks by 3% to 16%, particularly with strenuous sports. A significant interaction was observed between physical activity, sedentary behavior, and genetic predisposition in relation to stroke risk.

CONCLUSIONS

Among patients with metabolic dysfunction-associated fatty liver disease, higher leisure-time physical activity levels correlate with reduced CVD risks, while increased sedentary behavior is linked to higher CVD risks. Replacing sedentary time with physical activity consistently shows benefits in reducing CVD outcomes, irrespective of genetic predisposition.

Non-Linear Association of Dietary Polyamines with the Risk of Incident Dementia: Results from Population-Based Cohort of the UK Biobank

Natural polyamines, including spermidine (SPD), spermine (SPM) and putrescine (PUT), are evolutionarily conserved endogenous molecules crucially involved in central cellular processes. Their physiological importance may extend to the maintenance of cognitive function during aging. However, limited population-based epidemiological studies have explored the link between dietary polyamines and dementia risk. This study was a prospective analysis of 77,092 UK Biobank participants aged ≥ 60 years without dementia at baseline. We used Cox proportional hazard regression models to explore the associations between dietary polyamines and the risk of dementia, and restricted cubic splines to test the non-linear relationships. During a median follow-up of 12 years, 1087 incidents of all-cause dementia cases occurred, including 450 Alzheimer's disease (AD) cases and 206 vascular dementia (VD) cases. The fully adjusted hazard ratios (HRs) for the upper fourth quintile of dietary SPD, in comparison with the lowest quintile of intake, were 0.68 (95% confidence interval [95% CI]: 0.66-0.83) for the risk of all-cause dementia, 0.62 (95% CI: 0.45-0.85) for AD and 0.56 (95% CI: 0.36-0.88) for VD, respectively. A 26% reduction in dementia risk [HR: 0.74, (95% CI: 0.61-0.89)] and a 47% reduction in AD [HR: 0.53, (95%CI: 0.39-0.72)] were observed comparing the third with the lowest quintiles of dietary SPM. Dietary PUT was only associated with a reduced risk of all-cause dementia in the fourth quintile [HR (95% CI): 0.82 (0.68-0.99)]. Reduced risk was not found to be significant across all quintiles. There were 'U'-shaped relationships found between dietary polyamines and all-cause dementia, AD and VD. Stratification by genetic predisposition showed no significant effect modification. Optimal intake of polyamines was linked to a decreased risk of dementia, with no modification by genetic risk. This potentially suggests cognitive benefits of dietary natural polyamines in humans.

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.

Influence of Regular Physical Activity on Sleep

Good sleep and adequate physical activity are essential to health. Yet, large numbers of people are chronically deficient in sleep and physical activity. About 1 in 3 Americans get less than 7 h of sleep per night and only 1 of 4 adults regularly complete weekly physical activity in amounts recommended for good health. This chapter reviews research that has examined relationships between regular physical activity and sleep. The overall weight of evidence supports that regular physical activity is associated with better sleep quality among healthy adults, with epidemiological studies showing moderate-sized effects and more well-controlled randomized controlled trial experiments often showing larger effects. Large epidemiology studies suggest that the relationship between regular physical activity and better sleep quality may partially mediate the well-established associations between physical activity and reduced risk of mortality, cardiovascular diseases, and dementia. There is evidence that the completion of regular physical activity also is associated with better sleep quality among those with certain sleep disorders (i.e., insomnia, obstructive sleep apnea, and restless legs syndrome), mental health disorders (i.e., depression and posttraumatic stress disorder), and medical illnesses (i.e., breast cancer survivors). The evidence is inadequate to support that regular physical activity substantially improves sleep quality either (i) in children, adolescents, and older adults, (ii) in those with cancers except for breast cancer, (iii) in those with fibromyalgia, or (iv) among those with chronic kidney disease. Also, there is inadequate evidence to conclude that sleep quality is disrupted during weeks when competitive athletes engage in periods of overtraining.

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.