What is the association between sedentary behaviour and cognitive function? A systematic review

Calibrated to drive: Measuring self-assessed driving ability and perceived workload after prolonged sitting and sleep restriction

Self-assessed driving ability may differ from actual driving performance, leading to poor calibration (i.e., differences between self-assessed driving ability and actual performance), increased risk of accidents and unsafe driving behaviour. Factors such as sleep restriction and sedentary behaviour can impact driver workload, which influences driver calibration. This study aims to investigate how sleep restriction and prolonged sitting impact driver workload and driver calibration to identify strategies that can lead to safer and better calibrated drivers. Participants (n = 84, mean age = 23.5 ± 4.8, 49 % female) undertook a 7-day laboratory study and were randomly allocated to a condition: sitting 9-h sleep opportunity (Sit9), breaking up sitting 9-h sleep opportunity (Break9), sitting 5-h sleep opportunity (Sit5) and breaking up sitting 5-h sleep opportunity (Break5). Break9 and Break5 conditions completed 3-min of light-intensity walking on a treadmill every 30 min between 09:00-17:00 h, while participants in Sit9 and Sit5 conditions remained seated. Each participant completed a 20-min simulated commute in the morning and afternoon each day and completed subjective assessments of driving ability and perceived workload before and after each commute. Objective driving performance was assessed using a driving simulator measuring speed and lane performance metrics. Driver calibration was analysed using a single component and 3-component Brier Score. Correlational matrices were conducted as an exploratory analysis to understand the strength and direction of the relationship between subjective and objective driving outcomes. Analyses revealed participants in Sit9 and Break9 were significantly better calibrated for lane variability, lane position and safe zone-lane parameters at both time points (p < 0.0001) compared to Sit5 and Break5. Break5 participants were better calibrated for safe zone-speed and combined safe zone parameters (p < 0.0001) and speed variability at both time points (p = 0.005) compared to all other conditions. Analyses revealed lower perceived workload scores at both time points for Sit9 and Break9 participants compared to Sit5 and Break5 (p = <0.001). Breaking up sitting during the day may reduce calibration errors compared to sitting during the day for speed keeping parameters. Future studies should investigate if different physical activity frequency and intensity can reduce calibration errors, and better align a driver's self-assessment with their actual performance.

The Association of the 24-Hour Activity Cycle Profiles With Cognition in Older Adults With Mild Cognitive Impairment: A Cross-Sectional Study

BACKGROUND

The relationship of cognition and the 24-h activity cycle (24-HAC), encompassing physical activity, sedentary behavior, and sleep, in older adults with mild cognitive impairment (MCI) remains uncertain. Distinct combinations of 24-HAC behaviors can characterize unique activity profiles and influence cognition. We aimed to characterize 24-HAC activity profiles in older adults with MCI and assess whether differences in cognition exist across profiles.

METHODS

We conducted a cross-sectional analysis utilizing baseline data from 3 randomized controlled trials involving 253 community-dwelling older adults (55 + years) with MCI (no functional impairment, dementia diagnosis, and Montreal Cognitive Assessment score <26/30). Using MotionWatch8© wrist-worn actigraphy (+5 days), we captured the 24-HAC. Cognition was indexed by the Alzheimer's Disease Assessment Scale Cognitive Plus (ADAS-Cog-Plus). Compositional data and latent profile analyses identified distinct 24-HAC activity profiles. Analysis of covariance examined whether 24-HAC activity profiles differed in cognition.

RESULTS

Four distinct activity profiles were identified. Profile 1 ("Average 24-HAC," n = 103) engaged in all 24-HAC behaviors around the sample average. Profile 2 ("Active Chillers," n = 70) depicted lower-than-average engagement in physical activity and higher-than-average sedentary behavior. Profile 3 ("Physical Activity Masters," n = 54) were the most active and the least sedentary. Profile 4 ("Sedentary Savants," n = 26) were the least active and the most sedentary. Sleep was similar across profiles. There were no significant differences in ADAS-Cog-Plus scores between 24-HAC activity profiles (p > .05).

CONCLUSIONS

Older adults with MCI exhibited four 24-HAC activity profiles conforming to recommended physical activity and sleep guidelines. Nonetheless, cognition was similar across these profiles.

Physical activity, sedentary behaviour, and cognitive function among older adults: A bibliometric analysis from 2004 to 2024

Because of population ageing, there will be a vast increase in the prevalence of cognitive decline and dementia. Physical activity and sedentary behaviour have been identified as modifiable lifestyle behaviours associated with these cognitive conditions. Therefore, the aim of this bibliometric analysis is to reveal the knowledge structure of the field of physical activity, sedentary behaviour, and cognitive function among older adults from 2004 to 2024, and to predict emerging research trends. A total of 1290 publications were retrieved from the Web of Science Core Collection. CiteSpace and VOSviewer were applied to conduct performance analysis, science mapping, and enrichment. T. Liu-Ambrose was the most prolific author (39 publications), and the University of British Columbia was the most prolific institution (48 publications). The USA, China, and Canada were the three most productive countries with 392, 174, and 136 publications respectively. Two research trends revealed the knowledge structure of this field, including the shift from evaluating the effectiveness of interventions on cognitive function to evaluating the effectiveness of interventions on other health-related outcomes, as well as an expansion of research on the role of physical activity and sedentary behaviour in the context of healthy ageing. Sleep, sedentary behaviour, and virtual reality may be emerging research trends and may predict directions for future research. Collectively, this bibliometric analysis provides a one-step overview of the knowledge structure in this field for researchers and other stakeholders, as well as a reference for future research.

From "online brains" to "online lives": understanding the individualized impacts of Internet use across psychological, cognitive and social dimensions

In response to the mass adoption and extensive usage of Internet-enabled devices across the world, a major review published in this journal in 2019 examined the impact of Internet on human cognition, discussing the concepts and ideas behind the "online brain". Since then, the online world has become further entwined with the fabric of society, and the extent to which we use such technologies has continued to grow. Furthermore, the research evidence on the ways in which Internet usage affects the human mind has advanced considerably. In this paper, we sought to draw upon the latest data from large-scale epidemiological studies and systematic reviews, along with randomized controlled trials and qualitative research recently emerging on this topic, in order to now provide a multi-dimensional overview of the impacts of Internet usage across psychological, cognitive and societal outcomes. Within this, we detail the empirical evidence on how effects differ according to various factors such as age, gender, and usage types. We also draw from new research examining more experiential aspects of individuals' online lives, to understand how the specifics of their interactions with the Internet, and the impact on their lifestyle, determine the benefits or drawbacks of online time. Additionally, we explore how the nascent but intriguing areas of culturomics, artificial intelligence, virtual reality, and augmented reality are changing our understanding of how the Internet can interact with brain and behavior. Overall, the importance of taking an individualized and multi-dimensional approach to how the Internet affects mental health, cognition and social functioning is clear. Furthermore, we emphasize the need for guidelines, policies and initiatives around Internet usage to make full use of the evidence available from neuroscientific, behavioral and societal levels of research presented herein.

Isotemporal Substitution of Sedentary Time With Physical Activity Among Middle-Aged and Older Latinos: Effects on Episodic Memory

PURPOSE

To examine the estimated effects of substituting 30 min of sedentary time with low-light physical activity (LLPA) and high-light physical activity (HLPA) on episodic memory, executive functioning, and working memory among middle-aged and older Latinos.

DESIGN

A cross-sectional study.

SETTING

Chicago and Chicagoland suburbs.

SUBJECTS

Middle-aged and older Latinos (n = 61).

MEASURES

Accelerometer-assessed physical activity. A cognitive battery was administered to assess episodic memory, executive function, and working memory.

ANALYSIS

Isotemporal substitution analyses were conducted, where unstandardized coefficients from linear regression models were used to examine the substitution effect of replacing sedentary time with LLPA and HLPA.

RESULTS

Substitution of sedentary time with LLPA was associated with better episodic memory (Immediate recall, B = .947, P = .008; Delayed recall, B = .857, P = .013). No other significant substitution effects were present.

CONCLUSION

Middle-aged and older Latinos who replace sedentary time with LLPA may have better episodic memory. Future studies may target light physical activity to address cognition disparities and can inform the development of physical activity interventions that are appealing and accessible for Latinos.

Association between physical activity, peak expiratory flow, and cognitive function in aging: a cross-sectional analysis

BACKGROUND

The aging global population is experiencing escalating challenges related to cognitive deficits and dementia. This study explored the interplay between pulmonary function, physical activity, and cognitive function in older U.S. adults to identify modifiable risk factors for cognitive decline.

METHODS

Utilizing NHANES 2011-2012 data, we conducted a cross-sectional analysis of 729 participants aged ≥ 60 years. Cognitive function, peak expiratory flow (PEF), and physical activity were assessed. Weighted logistic regression and mediation analyses were employed to examine associations.

RESULTS

The sample size was 729 (weighted mean [SD] age, 67.1 [5.3] years; 53.6% female participants). Preliminary correlation analysis indicated a positive correlation between the global cognitive score and physical activity (β = 0.16; p < 0.001), recreational activity (β = 0.22; p < 0.001), and PEF in percent predicted (PEF%) (β = 0.18; p < 0.001). Compared to those with a PEF% >100%, the PEF% (80-100%) group (OR, 2.66; 95% CI, 1.34-5.29; p = 0.005) and PEF% <80% group (OR, 3.36; 95% CI, 1.67-6.76; p = 0.001) were significantly associated with higher cognitive deficits risk. Recreational activity meeting guidelines was linked to a lower risk of cognitive deficits (OR, 0.24; 95% CI, 0.10-0.57; p = 0.001). Mediation analysis demonstrated that PEF mediates the relationship between physical activity and cognitive function.

CONCLUSION

This study revealed significant associations between lower PEF, diminished physical activity, and increased cognitive deficits in elderly individuals. The results supported the hypothesis that pulmonary function may mediate the connection between activity and cognitive health, emphasizing the importance of respiratory health in cognitive aging. Recognizing these associations is crucial for clinical care and public health policy aiming to mitigate cognitive decline in aging populations. While these findings are intriguing, validation through longitudinal design studies is deemed necessary.

The effects of work on cognitive functions: a systematic review

Introduction

Cognitive functions play a crucial role in individual's life since they represent the mental abilities necessary to perform any activity. During working life, having healthy cognitive functioning is essential for the proper performance of work, but it is especially crucial for preserving cognitive abilities and thus ensuring healthy cognitive aging after retirement. The aim of this paper was to systematically review the scientific literature related to the effects of work on cognitive functions to assess which work-related factors most adversely affect them.

Method

We queried the PubMed and Scopus electronic databases, in February 2023, according to the PRISMA guidelines (PROSPERO ID number = CRD42023439172), and articles were included if they met all the inclusion criteria and survived a quality assessment. From an initial pool of 61,781 papers, we retained a final sample of 64 articles, which were divided into 5 categories based on work-related factors: shift work (n = 39), sedentary work (n = 7), occupational stress (n = 12), prolonged working hours (n = 3), and expertise (n = 3).

Results

The results showed that shift work, occupational stress, and, probably, prolonged working hours have detrimental effects on cognitive functioning; instead, results related to sedentary work and expertise on cognitive functions are inconclusive and extremely miscellaneous.

Discussion

Therefore, workplace health and well-being promotion should consider reducing or rescheduling night shift, the creation of less demanding and more resourceful work environments and the use of micro-breaks to preserve workers' cognitive functioning both before and after retirement.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023439172, identifier CRD42023439172.

Physical activity-related individual differences in functional human connectome are linked to fluid intelligence in older adults

The study examined resting state functional connectivity (rs-FC) associated with moderate-to-vigorous physical activity (MV-PA), sedentary time (ST), TV viewing, computer use, and their relationship to cognitive performance in older adults. We used pre-intervention data from 119 participants from the Fit & Active Seniors trial. Multivariate pattern analysis revealed two seeds associated with MV-PA: right superior frontal gyrus (SFG; spanning frontoparietal [FPN] and ventral attention networks [VAN]) and right precentral (PrG) and postcentral gyri (PoG) of the somatosensory network (SN). A positive correlation between the right SFG seed and a cluster spanning default mode (DMN), dorsal attention (DAN), FPN, and visual networks (VIS) was linked to higher fluid intelligence, as was FC between the right PrG/PoG seed and a cluster in VIS. No significant rs-FC patterns associated with ST, TV viewing, or computer use were found. Our findings suggest that greater functional integration within networks implementing top-down control and within those supporting visuospatial abilities, paired with segregation between networks critical and those not critical to top-down control, may help promote cognitive reserve in more physically active seniors.

Physical activity, musculoskeletal disorders, burnout, and work engagement: a cross-sectional study on Italian white-collar employees

Introduction

Both mental and physical health of office workers had a positive relationship with their work engagement, with the latter relationship being driven by the association of a healthy diet and physical activity (PA). This observational study aimed to investigate the associations between PA levels, musculoskeletal disorders (MSDs), burnout, and work engagement, in a sample of white-collar employees.

Methods

A total of 615 workers (age 42.2 ± 9.5 years) successfully completed an online questionnaire comprising work-related information and standardized questionnaires on PA, MSDs, burnout and work engagement.

Results

36.9% of the participants did not meet the PA guidelines, 19.0% adhered to them, and 44.1% exceeded them. A significant portion of participants reported suffering from MSDs, primarily neck/shoulder and/or low back/hip pain. Those exceeding PA guidelines had fewer MSDs compared to non-compliant participants and exhibited better mental health and work engagement. Compliance with PA guidelines was associated with a 38% reduced risk of emotional exhaustion, with an even greater reduction of 47% among those surpassing the guidelines.

Discussion

PA could exert a positive effect on physical and mental health of employees, but only if performed above a certain amount. The study supports the need to identify workplaces as suitable for health-focused interventions and lifestyle changes.

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.

Sedentary behavior and lifespan brain health

Higher levels of physical activity are known to benefit aspects of brain health across the lifespan. However, the role of sedentary behavior (SB) is less well understood. In this review we summarize and discuss evidence on the role of SB on brain health (including cognitive performance, structural or functional brain measures, and dementia risk) for different age groups, critically compare assessment approaches to capture SB, and offer insights into emerging opportunities to assess SB via digital technologies. Across the lifespan, specific characteristics of SB (particularly whether they are cognitively active or cognitively passive) potentially act as moderators influencing the associations between SB and specific brain health outcomes. We outline challenges and opportunities for future research aiming to provide more robust empirical evidence on these observations.

The causal relationship between physical activity, sedentary behavior and brain cortical structure: a Mendelian randomization study

Physical activity and sedentary behavior, both distinct lifestyle behaviors associated with brain health, have an unclear potential relationship with brain cortical structure. This study aimed to determine the causal link between physical activity, sedentary behavior, and brain cortical structure (cortical surface area and thickness) through Mendelian randomization analysis. The inverse-variance weighted method was primarily utilized, accompanied by sensitivity analyses, to confirm the results' robustness and accuracy. Analysis revealed nominally significant findings, indicating a potential positive influence of physical activity on cortical thickness in the bankssts (β = 0.002 mm, P = 0.043) and the fusiform (β = 0.002 mm, P = 0.018), and a potential negative association of sedentary behavior with cortical surface area in the caudal middle frontal (β = -34.181 mm2, P = 0.038) and the pars opercularis (β = -33.069 mm2, P = 0.002), alongside a nominally positive correlation with the cortical surface area of the inferior parietal (β = 58.332 mm2, P = 0.035). Additionally, a nominally significant negative correlation was observed between sedentary behavior and cortical thickness in the paracentral (β = -0.014 mm, P = 0.042). These findings offer insights into how lifestyle behaviors may influence brain cortical structures, advancing our understanding of their interaction with brain health.

Active workstations: A literature review on workplace sitting

The purpose of this paper is to further understand current literature on prolonged sitting, sitting posture and active sitting solutions. This paper is divided into three sections: The first section (Part I) is a comprehensive overview of the literature on how a static prolonged seated posture can affect: spinal health, trunk posture, contact pressure/discomfort development and vascular issues. The second section (Part II) reviews and qualitatively compares the four working postures recognized in ANSI/HFES 100-2007: reclined sitting, upright sitting, declined sitting and standing. The final section (Part III) is a summary of research on active chairs that revolves around the two types of movement patterns: 1- sustaining continual movement over a range of postures, occasionally reaching neutral lordosis, and 2- maintaining high frequency and duration of daily light contractile activity in the legs (or lower limbs).

A systematic review of the associations between sedentary behavior, physical inactivity, and non-motor symptoms of Parkinson's disease

BACKGROUND

Parkinson's disease (PD), known for motor symptoms, often presents early non-motor issues that significantly affect patients' quality of life. While effective treatments are limited, physical activity and exercise offer potential benefits. However, an overlooked aspect of the movement intensity continuum is prolonged sitting or sedentary behavior, and physical inactivity. Thus, this study aimed to conduct a systematic review investigating the associations between sedentary behavior, physical inactivity, and non-motor symptoms, specifically cognitive impairment, depression, and poor sleep in PD.

METHODS

Conforming to PRISMA guidelines, a systematic search of the literature was conducted via electronic databases including MEDLINE, CINAHL, Scopus, PubMed and PsycINFO up to February 28, 2023. Studies were included if they investigated associations between sedentary behavior or physical inactivity and at least one non-motor symptom such as depression, poor sleep, and/or cognitive impairment, in adults aged 18 years or older with PD. Quality assessment of the studies was performed using the Newcastle-Ottawa scale for cross-sectional and cohort studies.

RESULTS

Of the 463 publications found, 7 studies met the inclusion criteria (n = 980 unique participants). Sample sizes ranged from 17 to 487 participants, and all studies were observational, conducted in home or community settings. Collectively, these studies show that higher amounts of both objectively-measured and self-reported sedentary time are associated with worse scores on standardized measures of cognition and the Parkinson's Disease Questionnaire (PDQ) summary index and its subscales, such as cognition (memory and concentration). Additionally, longitudinal cohort studies suggest that physical inactivity and higher sedentary behavior are associated with depression and cognitive impairment in PD. Less sleep was associated with higher sedentary behavior.

CONCLUSION

Associations observed between physical inactivity, sedentary behavior, and non-motor symptoms in PD underscore the need to address these factors for enhanced well-being. Further well-designed studies are essential to assess the impact of reducing sedentary behavior and physical inactivity on non-motor symptoms in PD. Prospero registration number: PROSPERO (ID: CRD42023405422) on April 11, 2023.

Physical activity improves stress load, recovery, and academic performance-related parameters among university students: a longitudinal study on daily level

BACKGROUND

Physical activity has been proven to be beneficial for physical and psychological health as well as for academic achievement. However, especially university students are insufficiently physically active because of difficulties in time management regarding study, work, and social demands. As they are at a crucial life stage, it is of interest how physical activity affects university students' stress load and recovery as well as their academic performance.

METHODS

Student´s behavior during home studying in times of COVID-19 was examined longitudinally on a daily basis during a ten-day study period (N = 57, aged M = 23.5 years, SD = 2.8, studying between the 1st to 13th semester (M = 5.8, SD = 4.1)). Two-level regression models were conducted to predict daily variations in stress load, recovery and perceived academic performance depending on leisure-time physical activity and short physical activity breaks during studying periods. Parameters of the individual home studying behavior were also taken into account as covariates.

RESULTS

While physical activity breaks only positively affect stress load (functional stress b = 0.032, p < 0.01) and perceived academic performance (b = 0.121, p < 0.001), leisure-time physical activity affects parameters of stress load (functional stress: b = 0.003, p < 0.001, dysfunctional stress: b = -0.002, p < 0.01), recovery experience (b = -0.003, p < 0.001) and perceived academic performance (b = 0.012, p < 0.001). Home study behavior regarding the number of breaks and longest stretch of time also shows associations with recovery experience and perceived academic performance.

CONCLUSIONS

Study results confirm the importance of different physical activities for university students` stress load, recovery experience and perceived academic performance in home studying periods. Universities should promote physical activity to keep their students healthy and capable of performing well in academic study: On the one hand, they can offer opportunities to be physically active in leisure time. On the other hand, they can support physical activity breaks during the learning process and in the immediate location of study.

Relations between the levels of moderate to vigorous physical activity, BMI, dietary habits, cognitive functions and attention problems in 8 to 9 years old pupils: network analysis (PACH Study)

BACKGROUND

Physical activity (PA) and dietary habits (DH) play a crucial role on quality of life and health outcomes from various aspects.

METHODS

This study aims to investigate the relations between recommended daily levels of moderate to vigorous physical activity (MVPA) in 8 to 9 year old pupils, and their body mass index (BMI), DH, cognitive functions and attention problem scores by network analysis. Study participants were split into two groups based on their MVPA levels on weekdays.

RESULTS

Our findings suggest that children who reach recommended MVPA levels consume more vegetables and fruits, eat breakfast more frequently, have better motor speed and lower impulsivity score.

CONCLUSIONS

The number of interlinkages between various parameters in network structure for children who do not reach recommended MVPA levels is greater and more intense, highlighting the differences between the groups and suggesting that different interventions and approaches to improve/change lifestyle habits might be used.

Association between physical activity, body composition, and cognitive performance among female office workers

Regular physical activity can potentially prevent cognitive decline. While most studies focused on the general decline of the elderly and child and adolescent population, aging is a gradual process and cognitive decline can commence in middle age. Other than the middle-aged working population, gender-specific nuances are another overlooked area regarding the relationship between physical activity and cognitive performance. Therefore, this study examines the associations and benefits of maintaining regular physical activity habits with cognitive function and body composition in middle-aged female office workers. The results show that middle-aged females exhibited age-related declines in working memory, while no significant age-related changes are observed in reaction time and executive function. However, the regular exercise group demonstrates the ability to maintain their cognitive performance across age, unlike the sedentary group, who experiences declines in reaction time and executive function with age. Our findings highlight the significant impact of age on specific cognitive functions in middle-aged females and the positive influence of regular exercise on cognitive performance. Furthermore, this study demonstrates the potential of "the Brain Gym" App for efficient cognitive function assessment. The findings underscore the importance of regular exercise for cognitive well-being in middle-aged females and provide valuable insights into the relationship between body composition and cognitive function.

Feasibility of Identifying Factors Related to Alzheimer's Disease and Related Dementia in Real-World Data

A comprehensive view of factors associated with AD/ADRD will significantly aid in studies to develop new treatments for AD/ADRD and identify high-risk populations and patients for prevention efforts. In our study, we summarized the risk factors for AD/ADRD by reviewing existing meta-analyses and review articles on risk and preventive factors for AD/ADRD. In total, we extracted 477 risk factors in 10 categories from 537 studies. We constructed an interactive knowledge map to disseminate our study results. Most of the risk factors are accessible from structured Electronic Health Records (EHRs), and clinical narratives show promise as information sources. However, evaluating genomic risk factors using RWD remains a challenge, as genetic testing for AD/ADRD is still not a common practice and is poorly documented in both structured and unstructured EHRs. Considering the constantly evolving research on AD/ADRD risk factors, literature mining via NLP methods offers a solution to automatically update our knowledge map.

Effect of Fiber-Rich Diet and Rope Skipping on Memory, Executive Function, and Gut Microbiota in Young Adults: A Randomized Controlled Trial

SCOPE

To investigate the effects of fiber-rich diets (FDs), rope skipping (RS), and the combination of these two interventions (fiber-rich diet with rope skipping [FD-RS]) on memory, executive function in young adults, and to explore their relationship with gut microbiota.

MATERIALS AND RESULTS

The study is a 12-week parallel-design randomized controlled trial in which 120 undergraduates (19 ± 1 years) are randomized to FD (fiber ≥ 20 g day-1 ), RS (3 × 2000 times per week), FD-RS or control group (n = 30 per group). Memory and executive function are assessed by scales, and stool samples are collected at baseline and after the intervention. FD group and FD-RS group show fewer prospective and retrospective subjective memory impairments than the control group, but there is no significant difference between FD-RS and the intervention alone (FD or RS). No obvious change in executive function is observed throughout the trial. In terms of the gut microbiota, the α-diversity does not increase, but the microbial community evenness improves after the RS and FD intervention. Additionally, the relative abundance of phylum Firmicutes and genera Faecalibacterium, Eubacterium_coprostanoligenes_group in the RS group and NK4A214_group in the FD group significantly increase. In the RS group, a correlation is found between the increase in microbial evenness and the improvement in retrospective memory.

CONCLUSION

The FD and FD-RS have beneficial effects on memory in young adults. Meanwhile, FD and RS can improve the microbial evenness and increase several beneficial genera of phylum Firmicutes.

Breaking prolonged sitting increases 24-h physical activity and self-perceived energy levels but does not acutely affect cognition in healthy adults

INTRODUCTION

It is unknown whether predetermined (un)interrupted sitting within a laboratory setting will induce compensatory changes in human behaviours (energy intake and physical activity) once people return to a free-living environment. The effects of breaking up prolonged sitting on cognition are also unclear.

METHODS

Twenty-four (male = 13) healthy participants [age 31 ± 8 y, BMI 22.7 ± 2.3 kg/m2 (mean ± SD)] completed 320 min mixed-feeding trials under prolonged sitting (SIT) or with 2 min walking at 6.4 km/h every 20 min (ACTIVE), in a randomised crossover design. Human behaviours were recorded post-trial under free-living conditions until midnight. Cognitive performance was evaluated before and immediately after SIT and ACTIVE trials. Self-perceived sensations (appetite, energy and mood) and finger prick blood glucose levels were collected at regular intervals throughout the trials.

RESULTS

There were no differences between trials in eating behaviour and spontaneous physical activity (both, p > 0.05) in free-living conditions, resulting in greater overall total step counts [11,680 (10740,12620) versus 6049 (4845,7253) steps] and physical activity energy expenditure (PAEE) over 24-h period in ACTIVE compared to SIT (all, p < 0.05). Greater self-perceived levels of energy and lower blood glucose iAUC were found in ACTIVE trial compared to SIT trial (both, p < 0.05). No differences were found in cognitive performance between trials (all, p > 0.05).

CONCLUSION

Breaking up sitting does not elicit subsequent behavioural compensation, resulting in greater 24-h step counts and PAEE in healthy adults. Breaking up sitting reduces postprandial glucose concentrations and elicits greater self-perceived energy levels, but these positive effects do not acutely translate into improved cognitive function.

Appropriately Addressing Too Much Sitting as a Public Health Issue: Content Analysis of Coverage in the Five Major National Japanese Newspapers

Recent international public health guidelines now address reducing and breaking up time spent sitting (sedentary behavior). Japanese people spend considerable time sitting in workplaces and other contexts. With potential future public health guidelines in Japan, there is the need for greater public awareness of the importance of reducing sedentary time and of practical ways to do so. From the five major Japanese national newspapers, articles on sedentary behavior published between 2000 and 2021 were identified and coded for content analysis, including the main topic of the article, population group, sedentary behavior context or domain, health outcome, and solutions for reducing sedentary time. There were 53 articles identified, with sedentary behavior being the main topic in 22; workers as a population group appeared in 20 articles and workplaces as a domain in 22. More than 70% mentioned health influences, but fewer than 60% mentioned solutions. Further to informing the public about adverse health influences and consequences for workers and workplaces, there is also the need for improved coverage of the broader benefits of reducing sitting time, sedentary behavior among older adults and children, sitting in all aspects of daily life, and, importantly, considering public health guidelines and solutions for reducing prolonged sitting.

Relationship of Self-Reported Physical Activity with Cognition in Middle- Aged Adults

OBJECTIVE

The increasing prevalence of age-related cognitive decline highlights the importance of physical activity for cognitive health. Regular exercise has been associated with improved mental health and reduced risk of cognitive decline. This study investigated the connection between self-reported physical activity and cognitive function in middle-aged adults.

METHODS

This cross-sectional study included 56 Indian adults aged 30-55, selected based on a health screening questionnaire. Participants reported their physical activity using the International Physical Activity Questionnaire-Short Form (IPAQ-SF), which categorized them into low, moderate, and high activity levels. Cognitive functions, including visual memory, executive function, and attention, were assessed using the Cambridge Neuropsychological Automated Testing Battery (CANTAB). Results were statistically analyzed for relationships between cognitive domains and physical activity parameters using Pearson's correlation and linear regression analysis.

RESULTS

The study showed a significant positive correlation of attention with moderate and vigorous physical activity, while sedentary behavior negatively impacted attention. Linear regression showed that attention is affected by moderate-intensity activity whereas executive function and visual memory are affected by age.

CONCLUSION

This study supports the view that moderate and vigorous intensity activities may positively affect attention in middle-aged adults highlighting the benefits of physical activity.

The association between sedentary behaviour and sarcopenia in older adults: a systematic review and meta-analysis

BACKGROUND

Sedentary behaviour is considered to contribute to sarcopenia when combined with physical inactivity. Whether sedentary behaviour is independently associated with sarcopenia remains controversial. The aim of this study is to explore the association between sedentary behaviour and sarcopenia in older adults in community and long-term care facility settings.

METHODS

Eight electronic databases including MEDLINE, PsycINFO, Wanfang were searched from inception until August 2023. The review included cross-sectional and longitudinal studies concerning the association between sedentary behaviour and sarcopenia among participants over 60 years old. Evidence was pooled by both random-effects meta-analysis and narrative synthesis. Subgroup analyses explored variation according to adjustment of physical activity, settings, and measurements of sedentary behaviour and sarcopenia. Quality assessment for individual studies was performed with the Joanna Briggs Institute (JBI) Critical Appraisal Checklist.

RESULTS

Seventeen articles (16 cross-sectional studies and 1 longitudinal study) of 25,788 participants from community or long-term care facility settings were included. The overall quality of the included studies was rated high. Meta-analysis of 14 cross-sectional studies showed that sedentary behaviour was independently positively associated with sarcopenia: pooled odd ratio 1.36 (95% confidence interval, 1.18-1.58). The independent positive association remained in subgroup analyses by adjustment of physical activity, settings, and measurements of sedentary behaviour and sarcopenia. The narrative analysis corroborated the findings of the meta-analysis and provided additional evidence suggesting that interruptions in sedentary periods were linked to a decreased likelihood of developing sarcopenia.

CONCLUSIONS

The findings support the hypothesis that sedentary behaviour is independently positively associated with sarcopenia in older adults, providing vital indications for the development of strategies to prevent sarcopenia.

SYSTEMATIC REVIEW REGISTRATION

The systematic review protocol has been registered with the PROSPERO database (CRD42022311399).

Effects of intermittent exercise during prolonged sitting on executive function, cerebrovascular, and psychological response: a randomized crossover trial

Emerging evidence indicates that acute bouts of uninterrupted prolonged sitting decrease cerebral blood flow and impair executive function. Few studies have investigated the use of feasible sedentary behavior interruptions to attenuate these effects. This study aimed to investigate the effects of intermittent half-squat exercises during prolonged sitting on executive function. Twenty participants (45% women, 21 ± 1 yr) were randomized to sit for 3 h 1) without any interruptions (control) or 2) with 1 min half-squats every 20 min (exercise). Executive function was determined using the Color Word Stroop Test (CWST) and Trail Making Test-B (TMT-B). Subjective feelings of arousal and measures of fatigue, concentration, and motivation were evaluated. Internal carotid artery (ICA) blood flow was measured using Doppler ultrasound. There was a significant interaction effect for correct response times with the incongruent CWST (P < 0.01), which were 3.5% faster in the exercise and 4.2% slower in the control over 3 h of sitting. There was also a significant interaction effect for TMT-B completion times (P < 0.01), which were 10.0% faster in the exercise and 8.8% slower in the control. Exercise suppressed decreases in concentration with a significant interaction effect (-28.7% vs. -9.2% for control vs. exercise, P = 0.048) and increases in mental fatigue with a significant interaction effect (285% vs. 157% for control vs. exercise, P < 0.04). These changes may have been related to changes in ICA blood flow, which had a significant interaction effect (P = 0.087). These results suggest that a simple strategy like intermittent squat exercises could help to maintain executive function during prolonged sitting.NEW & NOTEWORTHY We assessed executive function, cardiovascular, and cerebrovascular responses during 3-h prolonged sitting, with or without an exercise interruption (1 min squats every 20 min). Compared to uninterrupted sitting, exercise interruption suppressed sitting-induced reductions in cerebral blood flow and impairments in executive function. These results demonstrated the efficacy of a half-squat intervention for individuals seeking to preserve cognition during prolonged sitting, which may be useful in environments with limited resources such as the workplace.

Outcomes Associated With Translating Evidence-Based Research Into Practice: The Physical Activity for Lifelong Success Program

BACKGROUND

Few programs assess for outcomes once translated into practice. The Physical Activity for Lifelong Success program was developed as a center-based public health intervention and shown to improve walking speed and distance among older adults with type 2 diabetes. We adapted the program for community-based delivery by lay leaders to physically inactive older adults.

METHODS

We followed the Replicating Effective Programs framework to identify community stakeholders, adapt, implement, and evaluate fidelity of delivery in community settings, and plan for maintenance and evolution. Sixteen community sites enrolled 184 adults (mean age 73.5 y, 85% female, 93% White) in 21 workshops. Baseline and postworkshop measures assessed participants' health-related quality of life, physical function, and physical fitness. Data were analyzed using Fisher exact tests, Student t test, and paired linear regression with fixed effects.

RESULTS

Fidelity testing indicated leader training was sufficient to maintain key elements with delivery. Data from 122 participants showed improvements in chair stands (P < .001), arm curls (P < .001), 2-minute step test (P < .001), sit-and-reach (P = .001), 8-foot up-and-go (P < .001), and 10-m walk (P < .001).

CONCLUSIONS

Adaptation of Physical Activity for Lifelong Success for implementation by community organizations for physically inactive older adults demonstrates that fidelity and effectiveness can be maintained after program translation.

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.

Accelerometry measures of physical activity and sedentary behavior: Associations with cognitive functioning in MS

BACKGROUND

Cognitive dysfunction is a pervasive symptom of multiple sclerosis (MS). Correlational evidence on the relationships between physical activity, sedentary behavior, and cognition has been mixed and limited to a few activity measures. The collinearity of accelerometry-based metrics has precluded an assessment of the full activity spectrum. Here, we aimed to examine the rich set of activity measures using analytic approaches suitable for collinear metrics. We investigated the combination of physical activity, sedentary, and clinicodemographic measures that explain the most variance in composite scores of working memory/processing speed, visual memory, and verbal memory.

METHODS

We analyzed baseline accelerometry and neuropsychological data (n = 80) from a randomized controlled trial of pedometer tracking. Using partial least squares regression (PLSR), we built three models to predict latent scores on the three domains of cognition using 12 activity metrics, sex, education, and Expanded Disability Status Scale (EDSS) scores. Significance was assessed using linear regression models with model component scores as predictors and cognitive composites as outcomes.

RESULTS

The latent component was significant for working memory/processing speed but was not significant for visual memory and verbal memory after Bonferroni correction. Working memory/processing speed was positively associated with average kilocalories, moderate-to-vigorous physical activity (MVPA), steps, and sex (i.e., higher scores in males) and negatively related to duration of long sedentary bouts and EDSS.

CONCLUSIONS

These findings suggest that increasing overall energy expenditure through walking and MVPA, while decreasing prolonged sedentary time may positively benefit working memory/processing speed in people with MS.

TRIAL REGISTRATION

This RCT #NCT03244696 was registered on Clinicaltrials.gov (https://www.

CLINICALTRIALS

gov/ct2/show/NCT03244696).

Changes in physical activity, sedentary behavior, and self-reported cognitive function in cancer survivors before and during the COVID-19 pandemic: A cross-sectional study

BACKGROUND

Physical activity (PA) and reductions in sedentary behavior (SED) may mitigate cancer-related cognitive impairment. The purpose of this study was to examine (a) the associations between changes in PA, SED, and cognitive function in cancer survivors before and during the coronavirus disease 2019 (COVID-19) pandemic; and (b) clinical subgroups that moderate this association.

METHODS

A cross-sectional survey was administered online to adult cancer survivors globally between July and November of 2020. This was a secondary analysis of a cross-sectional survey examining changes in self-reported PA and quality of life in cancer survivors before and during the COVID-19 pandemic. Self-reported Questionnaires assessed moderate-to-vigorous PA (MVPA) using the modified Godin Leisure Time Exercise Questionnaire, cognitive function using the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) scale, and SED using the Domain-specific Sitting Time questionnaire. Cancer survivors were classified into no change in behavior, desirable change (i.e., increase MVPA to meet PA guidelines or decrease SED by ≥60 min/day), and undesirable change (i.e., decrease MVPA to <150 min/week or increase SED by ≥60 min/day). Analysis of covariance examined differences in FACT-Cog scores across the activity change categories. Planned contrasts compared differences in FACT-Cog scores between cancer survivors with (a) no meaningful change vs. any change, and (b) a desirable change vs. an undesirable change.

RESULTS

There were no significant differences in FACT-Cog scores across activity-change categories in the full sample of cancer survivors (n = 371; age = 48.6 ± 15.3 years (mean ± SD)). However, cancer survivors who were diagnosed ≥5 years ago (t(160) = -2.15, p = 0.03) or who received treatment ≥5 years ago (t(102) = -2.23, p = 0.03) and who had a desirable change in activity reported better perceived cognitive abilities than those who had an undesirable change.

CONCLUSION

PA promotion efforts should consider reducing SED in addition to maintaining MVPA in long-term cancer survivors to mitigate cancer-related cognitive impairment during the COVID-19 pandemic.

Groove Rhythm Enhances Exercise Impact on Prefrontal Cortex Function in Groove Enjoyers

A positive affective response modulates the effects of aerobic exercise on prefrontal executive function (EF). Groove rhythm (GR), eliciting the feeling of wanting to move to music, is useful for inducing positive affective response during exercise. Three minutes of listening to GR activated the left dorsolateral prefrontal cortex (l-DLPFC) and enhanced EF in participants who had higher psychological responses to GR. This finding prompted us to test the hypothesis that the combination of GR and exercise (GREX) induces positive psychological responses that enhance PFC function through entrainment of body movements and musical beats. 41 participants were administered two experimental conditions: three min of very light-intensity (30% V̇ O2peak) exercise combined with GR and combined with a white-noise metronome (WMEX). Before and after exercise, participants performed a Stroop task and were monitored for l-DLPFC activity with functional near-infrared spectroscopy. GREX enhanced EF and l-DLPFC activity in participants who experienced greater subjective feelings of audiomotor entrainment and increased excitement with GREX. These psychological responses were predictive of the impact of GREX on l-DLPFC activity and EF. These findings, together with previous results, support the hypothesis that GR allows us to boost the cognitive benefits of exercise via l-DLPFC activity only in those who enjoy groove, and suggest that subjective audiomotor entrainment is a key mechanism of this boosting effect.

Association between physical activity measured by accelerometry and cognitive function in older adults: a systematic review

OBJECTIVE

To analyze studies that investigated the association between physical activity assessed by accelerometry and cognitive function in older people.

METHODS

A systematic review was carried out in four electronic databases (PubMed, Web of Science, Scopus, and SportsDiscus).

RESULTS

In total, 195 records were identified. Fifty-two studies were selected for a full evaluation; 23 were selected according to the inclusion criteria adopted and divided into four chapters (characteristics of the studies, the association between physical activity level and cognitive function decline, effects of physical activity in reducing the chances of cognitive function decline and effects of physical activity on brain plasticity. The cross-sectional studies had an average score of 7 points, and the cohort studies obtained 10 points, indicating the high quality of the selected studies. Seven studies indicated an association between Moderate to vigorous physical activities (MVPA) and cognitive function, two specifically indicated a reduction in the chances of cognitive function decline according to the interquartile of MVPA, and three studies indicated improvements in MVPA in brain plasticity.

CONCLUSION

Measured by accelerometry, seems to be favorably associated with important outcomes in cognitive function assessed through questionnaires, imaging analyses, and biochemical markers with older adults.

Association of physical activity and fitness with executive function among preschoolers

It is well-documented in the literature that high levels of regular physical activity (PA), low levels of sedentary behavior (SB), and high levels of cardiorespiratory fitness (CRF) are associated with superior cognitive functioning, especially with regard to older populations. However, concerning other age groups (e.g., preschoolers) the available evidence documenting such a positive relationship is relatively scarce. Thus, this study aimed to investigate the association of time spent in different PA intensity zones and CRF with executive functions (EFs) in preschool-age children. To this end, preschoolers (n = 127) aged 3 to 6 years were recruited from 9 kindergarten classes in 2 districts of Shenzhen, China. The amount and the intensity of PA were assessed via accelerometry, and the CRF level was quantified by the 20-meter shuttle run test. EFs including inhibitory control and working memory were assessed using the one-on-one iPad-based Early Year Toolbox. Results suggested that children who had a higher CRF level ("impulse control" scores: β = 0.34, p < .001; "Go" accuracy: β = 0.31, p < .001; "No-Go" accuracy: β =0.28, < .001) and spentmore time in moderate-to-vigorous physical activity (MVPA) ("impulse control" scores: β = 0.50, p < .001; No-Go" accuracy: β = 0.52, p < .001) had higher scores on inhibitory control tasks, and those who had a higher CRF level had higher scores on a working memory task (β = 0.24, p < .05). The findings are discussed in light of the positive roles of MVPA and CRF for promoting EFs, but also consider the disproportionate association of PA and CRF with working memory relative to inhibition.

Physiology of sedentary behavior

Sedentary behaviors (SB) are characterized by low energy expenditure while in a sitting or reclining posture. Evidence relevant to understanding the physiology of SB can be derived from studies employing several experimental models: bed rest, immobilization, reduced step count, and reducing/interrupting prolonged SB. We examine the relevant physiological evidence relating to body weight and energy balance, intermediary metabolism, cardiovascular and respiratory systems, the musculoskeletal system, the central nervous system, and immunity and inflammatory responses. Excessive and prolonged SB can lead to insulin resistance, vascular dysfunction, shift in substrate use toward carbohydrate oxidation, shift in muscle fiber from oxidative to glycolytic type, reduced cardiorespiratory fitness, loss of muscle mass and strength and bone mass, and increased total body fat mass and visceral fat depot, blood lipid concentrations, and inflammation. Despite marked differences across individual studies, longer term interventions aimed at reducing/interrupting SB have resulted in small, albeit marginally clinically meaningful, benefits on body weight, waist circumference, percent body fat, fasting glucose, insulin, HbA1c and HDL concentrations, systolic blood pressure, and vascular function in adults and older adults. There is more limited evidence for other health-related outcomes and physiological systems and for children and adolescents. Future research should focus on the investigation of molecular and cellular mechanisms underpinning adaptations to increasing and reducing/interrupting SB and the necessary changes in SB and physical activity to impact physiological systems and overall health in diverse population groups.

Maintaining brain health across the lifespan

Across the lifespan, the human body and brain endure the impact of a plethora of exogenous and endogenous factors that determine the health outcome in old age. The overwhelming inter-individual variance spans between progressive frailty with loss of autonomy to largely preserved physical, cognitive, and social functions. Understanding the mechanisms underlying the diverse aging trajectories can inform future strategies to maintain a healthy body and brain. Here we provide a comprehensive overview of the current literature on lifetime factors governing brain health. We present the growing body of evidence that unhealthy alimentary regime, sedentary behaviour, sleep pathologies, cardio-vascular risk factors, and chronic inflammation exert their harmful effects in a cumulative and gradual manner, and that timely and efficient intervention could promote healthy and successful aging. We discuss the main effects and interactions between these risk factors and the resulting brain health outcomes to follow with a description of current strategies aiming to eliminate, treat, or counteract the risk factors. We conclude that the detailed insights about modifiable risk factors could inform personalized multi-domain strategies for brain health maintenance on the background of increased longevity.

Leisure-Time Television Viewing and Computer Use, Family History, and Incidence of Dementia

INTRODUCTION

Time spent on screen-based sedentary activities is significantly associated with dementia risk, however, whether the associations vary by family history (FHx) of dementia is currently unknown. We aimed to examine independent associations of two prevalent types of screen-based sedentary activities (television [TV] viewing and computer use) with dementia and assess the modifying effect of FHx.

METHODS

We included 415,048 individuals free of dementia from the UK Biobank. Associations of TV viewing, computer use, and FHx with dementia risk were determined using Cox regression models. We estimated both multiplicative- and additive-scale interactions between TV viewing and computer use and FHx.

RESULTS

During a median follow-up of 12.6 years, 5,549 participants developed dementia. After adjusting for potential confounding factors, we observed that moderate (2-3 h/day; hazard ratio [HR] 1.13, 95% confidence interval 0.03-1.23) and high (>3 h/day; 1.33, 1.21-1.46) TV viewing was associated with a higher dementia risk, compared with low (0-1 h/day) TV viewing. Using restricted cubic spline models, the relationship of TV viewing with dementia was nonlinear (relative to 0 h/day; p for nonlinear = 0.005). We found that >3 h/day of TV viewing was associated with a 42% (1.42, 1.18-1.71) higher dementia risk in participants with FHx while a 30% (1.30, 1.17-1.45) in those without FHx. For computer use, both low (0 h/day; 1.41, 1.33-1.50) and high (>2 h/day; 1.17, 1.05-1.29) computer use were associated with elevated dementia risk, compared with moderate (1-2 h/day) computer use. We observed a J-shaped relationship with dementia (relative to 2 h/day; p for nonlinear <0.001). Compared with 1-2 h/day of computer use, the HRs of dementia were 1.46 (1.29-1.65) and 1.10 (0.90-1.36) for 0 h/day and >2 h/day of computer use in participants with FHx, respectively, while the corresponding HRs were 1.40 (1.30-1.50) and 1.19 (1.06-1.33) in those without FHx. We observed a positive additive interaction (RERI 0.29, 0.06-0.53) between computer use and FHx, while little evidence of interaction between TV viewing and FHx.

CONCLUSIONS

The time spent on TV viewing and computer use were independent risk factors for dementia, and the adverse effects of computer use and FHx were additive. Our findings point to new behavioral targets for intervention on preventing an early onset of dementia, especially for those with FHx.

Sedentary Behavior and Incident Dementia Among Older Adults

Importance

Sedentary behavior is associated with cardiometabolic disease and mortality, but its association with dementia is unclear.

Objective

To investigate whether accelerometer-assessed sedentary behavior is associated with incident dementia.

Design, Setting, and Participants

A retrospective study of prospectively collected data from the UK Biobank including 49 841 adults aged 60 years or older without a diagnosis of dementia at the time of wearing the wrist accelerometer and living in England, Scotland, or Wales. Follow-up began at the time of wearing the accelerometer (February 2013 to December 2015) and continued until September 2021 in England, July 2021 in Scotland, and February 2018 in Wales.

Exposures

Mean daily sedentary behavior time (included in the primary analysis) and mean daily sedentary bout length, maximum daily sedentary bout length, and mean number of daily sedentary bouts (included in the secondary analyses) were derived from a machine learning-based analysis of 1 week of wrist-worn accelerometer data.

Main Outcome and Measures

Incident all-cause dementia diagnosis from inpatient hospital records and death registry data. Cox proportional hazard models with linear and cubic spline terms were used to assess associations.

Results

A total of 49 841 older adults (mean age, 67.19 [SD, 4.29] years; 54.7% were female) were followed up for a mean of 6.72 years (SD, 0.95 years). During this time, 414 individuals were diagnosed with incident all-cause dementia. In the fully adjusted models, there was a significant nonlinear association between time spent in sedentary behavior and incident dementia. Relative to a median of 9.27 hours/d for sedentary behavior, the hazard ratios (HRs) for dementia were 1.08 (95% CI, 1.04-1.12, P < .001) for 10 hours/d, 1.63 (95% CI, 1.35-1.97, P < .001) for 12 hours/d, and 3.21 (95% CI, 2.05-5.04, P < .001) for 15 hours/d. The adjusted incidence rate of dementia per 1000 person-years was 7.49 (95% CI, 7.48-7.49) for 9.27 hours/d of sedentary behavior, 8.06 (95% CI, 7.76-8.36) for 10 hours/d, 12.00 (95% CI, 10.00-14.36) for 12 hours/d, and 22.74 (95% CI, 14.92-34.11) for 15 hours/d. Mean daily sedentary bout length (HR, 1.53 [95% CI, 1.03-2.27], P = .04 and 0.65 [95% CI, 0.04-1.57] more dementia cases per 1000 person-years for a 1-hour increase from the mean of 0.48 hours) and maximum daily sedentary bout length (HR, 1.15 [95% CI, 1.02-1.31], P = .02 and 0.19 [95% CI, 0.02-0.38] more dementia cases per 1000 person-years for a 1-hour increase from the mean of 1.95 hours) were significantly associated with higher risk of incident dementia. The number of sedentary bouts per day was not associated with higher risk of incident dementia (HR, 1.00 [95% CI, 0.99-1.01], P = .89). In the sensitivity analyses, after adjustment for time spent in sedentary behavior, the mean daily sedentary bout length and the maximum daily sedentary bout length were no longer significantly associated with incident dementia.

Conclusions and Relevance

Among older adults, more time spent in sedentary behaviors was significantly associated with higher incidence of all-cause dementia. Future research is needed to determine whether the association between sedentary behavior and risk of dementia is causal.

Differentiating the influence of sedentary behavior and physical activity on brain health in late adulthood

Public health messaging calls for individuals to be more physically active and less sedentary, yet these lifestyle behaviors have been historically studied independently. Both physical activity (PA) and sedentary behavior (SB) are linked through time-use in a 24-hour day and are related to health outcomes, such as neurocognition. While the benefits of PA on brain health in late adulthood have been well-documented, the influence of SB remains to be understood. The purpose of this paper was to critically review the evolving work on SB and brain health in late adulthood and emphasize key areas of consideration to inform potential research. Overall, the existing literature studying the impact of SB on the components and mechanisms of brain health are mixed and inconclusive, provided largely by cross-sectional and observational work employing a variety of measurement techniques of SB and brain health outcomes. Further, many studies did not conceptually or statistically account for the role of PA in the proposed relationships. Therefore, our understanding of the way in which SB may influence neurocognition in late adulthood is limited. Future efforts should include more prospective longitudinal and randomized clinical trials with intentional methodological approaches to better understand the relationships between SB and the brain in late adulthood, and how these potential links are differentiated from PA.

Association between sedentary behavior and risk of cognitive decline or mild cognitive impairment among the elderly: a systematic review and meta-analysis

Background

Existing evidence on the association between sedentary behavior (SB) and cognitive function remains inconclusive. Therefore, this study investigated the association between SB and the risk of cognitive decline (CD) or mild cognitive impairment (MCI) in the elderly.

Methods

A comprehensive search was independently conducted by two researchers (XC and GQ) in seven electronic databases, including Medline (via PubMed), China Biology Medicine, Embase, Web of Science, China National Knowledge Infrastructure, Wanfang database, and VIP database for Chinese technical periodicals, covering studies published from the inception of database to June 2023. Studies that investigated the relationship between SB and the risk of CD or MCI in the elderly were included. The quality of the literature was assessed using the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) assessment tools. The combined effect size analysis, subgroup analysis, and publication bias assessment were performed using STATA 14.0.

Results

A total of 13 cross-sectional and 6 cohort studies involving 81,791 individuals were included, comprising 17 high-quality studies and 2 medium-quality studies. We found that SB was significantly associated with an increased risk of CD [odds ratio (OR) = 1.69, 95% confidence intervals (CI): 1.47-1.94] or MCI (OR = 1.34, 95% CI: 1.14-1.56) among the elderly. Subgroup analysis stratified according to comorbidity, lifestyle, family structure, publication year, and region showed statistical differences between groups, and the consistency of the results revealed the sources of the heterogeneity.

Conclusion

This meta-analysis showed that SB is positively associated with the risk of CD or MCI in the elderly, providing a higher level of evidence for the promotion of healthy behaviors by clinicians and health policymakers. Due to the number and quality of the included articles, more high-quality longitudinal studies are needed to further confirm our findings.

The causality of physical activity status and intelligence: A bidirectional Mendelian randomization study

BACKGROUND

Observational studies suggest physical activity (PA) enhances intelligence, while sedentary behavior (SB) poses a risk. However, causality remains unclear.

METHODS

We extracted genetic instruments from large genome-wide association studies summary data and employed an inverse-variance weighted (IVW) approach within a random-effects model as the primary method of Mendelian randomization (MR) analysis to estimate the overall effect of various physical activity statuses on intelligence. To assess IVW stability and MR sensitivity, we also utilized supplementary methods including weighted median, MR-Egger, and MR-PRESSO. Furthermore, multivariable MR analysis was conducted to examine the independent effects of each physical activity trait on intelligence.

RESULTS

The MR primary results indicated that LST was negatively associated with intelligence (β = -0.133, 95%CI: -0.177 to -0.090, p = 1.34×10-9), while SBW (β = 0.261, 95% CI: 0.059 to 0.463, p = 0.011) may have a positive effect on intelligence; however, MVPA and SC did not show significant effects on intelligence. Inverse causality analyses demonstrated intelligence significantly influenced all physical activity states.

CONCLUSIONS

Our study highlights a bidirectional causal relationship between physical activity states and intelligence.

Physical activity in adults with epilepsy: clinical aspects and relationship with cognition and quality of life

There are several factors associated with lower participation in regular physical activity (PA) in adult patients with epilepsy (PWEs).

Objective

To assess the relationship between the regular practice of PA with clinical and cognitive variables and quality of life (QoL) in PWEs.

Methods

Habitual Physical Activity Questionnaire (HPAQ) was related to clinical variables, scores on the Mini-Mental State Examination (MMSE), on the Brief Cognitive Battery-Edu (BCB-Edu), on the Satisfaction Scale for Physical Activity (SSPA), and on the Quality of Life in Epilepsy Inventory (QOLIE)-31 in 60 PWEs, with a significance level of p<0.05.

Results

The PWEs had a mean age of 42.4±13.6 years, 50% of whom were female. Longer length of epilepsy correlated with lower PA in leisure time (Pearson correlation [r]= -0.276; p-value [p]=0.036). The occupational physical activity scores of the HPAQ correlated positively with perception (r=0.300; p=0.021), memory (r=0.381; p=0.003), semantic verbal fluency test (SVF) (r=0.427; p=0.001), and with the total score in the MMSE (r=0.327; p=0.012). The total HPAQ score correlated with the SVF (r=0.336; p=0.009) and with the MMSE (r=0.254; p=0.049). There was no correlation among the QOLIE-31, the HPAQ, and the SSPA.

Conclusions

Longer duration of epilepsy was associated with the lower practice of PA. Physical activity was associated with better performance in aspects of cognition. There was no relationship between QoL and practice and satisfaction with PA, suggesting different psychosocial aspects involved.

Impact of physical activity levels on the ability to maintain static trunk posture in older adults

PROPOSE

to assess the impact of physical activity (PA) levels on sitting posture in the older adults.

METHODS

One hundred and twenty individuals were divided into three groups according their PA levels: vigorous group (VG); moderate group (MG); low group (LG). The ability to maintain static trunk posture in sitting position as assessed based on the cervical angle (CA) and thoracic angle (TA) was measured.

RESULTS

There were no significant differences between measurements in CA for the VG. However, LG and MG participants exhibited a significant decrease in CA from minute 1 to 10 and from minute 2 to 10, respectively. In the thoracic region, only the MG exhibited significant differences in TA from minute 2 to 10 compared to minute 1 (p < 0.05). No significant differences were found in TA between measurements for either VG or LG.

CONCLUSIONS

PA has a high impact on the ability to maintain static trunk posture in the older adults.

Associations between change in physical activity and sedentary time and health-related quality of life in older english adults: the EPIC-Norfolk cohort study

BACKGROUND

No previous studies have examined the associations between changes in objectively-measured physical behaviours with follow-up QoL in older adults. Based on cross-sectional evidence, it is biologically plausible that such associations exist. If so, this bolsters the case for the commissioning of activity interventions and for including QoL as an outcome in trials of such interventions.

METHODS

We assessed physical behaviours (total physical activity, moderate-to-vigorous physical activity (MVPA), light physical activity, total sedentary time and prolonged sedentary bout time) for 7 days using hip-worn accelerometers at baseline (2006-2011) and follow-up (2012-2016) and health-related quality-of-life (QoL) using EQ-5D questionnaires at follow-up in 1433 participants (≥ 60 years) of the EPIC (European Prospective Investigation into Cancer)-Norfolk study. The EQ-5D summary score was used, with 0 as the worst to 1 as best perceived quality-of-life. We evaluated the prospective associations of baseline physical behaviours with follow-up QoL, and of changes in behaviours with follow-up QoL using multi-level regression.

RESULTS

On average, MVPA decreased by 4.0 min/day/year (SD 8.3) for men and 4.0 min/day/year for women (SD 12.0) between baseline and follow-up. Total sedentary time increased by an average 5.5 min/day/yr (SD 16.0) for men and 6.4 min/day/yr (SD 15.0) for women between baseline and follow-up. Mean (SD) follow-up time was 5.8 (1.8) years. We found that higher baseline MVPA and lower sedentary time was associated with higher subsequent QoL (e.g. 1 h/day greater baseline MVPA was associated with 0.02 higher EQ-5D score, 95% CI 0.06, 0.36). More pronounced declines in activity were associated with worse Hr-QoL (0.005 (95% CI 0.003, 0.008) lower EQ-5D per min/day/yr decrease in MVPA). Increases in sedentary behaviours were also associated with poorer QoL (0.002 lower EQ-5D, 95% CI -0.003, -0.0007 per hour/day/yr increase in total sedentary time).

CONCLUSIONS

Promotion of physical activity and limiting sedentary time among older adults may improve quality-of-life, and therefore this relationship ought to be included in future cost effectiveness analyses so that greater commissioning of activity interventions can be considered.

Validation of an Algorithm for Measurement of Sedentary Behaviour in Community-Dwelling Older Adults

Accurate measurement of sedentary behaviour in older adults is informative and relevant. Yet, activities such as sitting are not accurately distinguished from non-sedentary activities (e.g., upright activities), especially in real-world conditions. This study examines the accuracy of a novel algorithm to identify sitting, lying, and upright activities in community-dwelling older people in real-world conditions. Eighteen older adults wore a single triaxial accelerometer with an onboard triaxial gyroscope on their lower back and performed a range of scripted and non-scripted activities in their homes/retirement villages whilst being videoed. A novel algorithm was developed to identify sitting, lying, and upright activities. The algorithm's sensitivity, specificity, positive predictive value, and negative predictive value for identifying scripted sitting activities ranged from 76.9% to 94.8%. For scripted lying activities: 70.4% to 95.7%. For scripted upright activities: 75.9% to 93.1%. For non-scripted sitting activities: 92.3% to 99.5%. No non-scripted lying activities were captured. For non-scripted upright activities: 94.3% to 99.5%. The algorithm could, at worst, overestimate or underestimate sedentary behaviour bouts by ±40 s, which is within a 5% error for sedentary behaviour bouts. These results indicate good to excellent agreement for the novel algorithm, providing a valid measure of sedentary behaviour in community-dwelling older adults.

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.

Association between sedentary behavior and depression in US adults with chronic kidney disease: NHANES 2007-2018

BACKGROUND

Depression increases the risk of adverse clinical outcomes in patients with chronic kidney disease. Physical activity has been shown to improve depressive symptoms in this population, but the relationship of sedentary behavior with depression has not been studied. In this study, we examined the relationship between sedentary behavior and depression in patients with chronic kidney disease.

METHODS

This cross-sectional study included 5,205 participants aged ≥ 18 years with chronic kidney disease participating in the 2007-2018 National Health and Nutrition Examination Survey. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). Recreation activity, work activity, walking or cycling for transportation, and sedentary behavior were measured using the Global Physical Activity Questionnaire. A series of weighted logistic regression models were used to investigate the aforementioned relationship.

RESULTS

The prevalence of depression among US adults with chronic kidney disease was 10.97% in our study. In addition, sedentary behavior was strongly associated with higher levels of depressive symptoms, as measured by the PHQ-9 (P < 0.001). In the fully adjusted model, we found that compared with participants who had shorter durations of sedentary behavior, participants who had the highest durations of sedentary behavior had 1.69 times (odd ratio 1.69, 95% confidence interval: 1.27, 2.24) greater risk of being clinically depressed. After adjusting for confounding factors, subgroup analyses showed that the association between sedentary behavior and depression still existed in all stratifications.

CONCLUSION

We found an association between longer duration of sedentary behavior and more severe depression in US adults with chronic kidney disease; however, prospective studies with larger sample sizes are still needed to confirm the effects of sedentary behavior on depression in the chronic kidney disease population.

Wrist-worn sensor-based measurements for drug effect detection with small samples in people with Lewy Body Dementia

INTRODUCTION

Few late-stage clinical trials in Parkinson's disease (PD) have produced evidence on the clinical validity of sensor-based digital measurements of daily life activities to detect responses to treatment. The objective of this study was to assess whether digital measures from patients with mild-to-moderate Lewy Body Dementia demonstrate treatment effects during a randomized Phase 2 trial.

METHODS

Substudy within a 12-week trial of mevidalen (placebo vs 10, 30, or 75 mg), where 70/344 patients (comparable to the overall population) wore a wrist-worn multi-sensor device.

RESULTS

Treatment effects were statistically significant by conventional clinical assessments (Movement Disorder Society-Unified Parkinson's Disease Rating Scale [MDS-UPDRS] sum of Parts I-III and Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change [ADCS-CGIC] scores) in the full study cohort at Week 12, but not in the substudy. However, digital measurements detected significant effects in the substudy cohort at week 6, persisting to week 12.

CONCLUSIONS

Digital measurements detected treatment effects in a smaller cohort over a shorter period than conventional clinical assessments.

TRIAL REGISTRATION

clinicaltrials.gov, NCT03305809.

Effects of breaking up sitting with light-intensity physical activity on cognition and mood in university students

BACKGROUND

University students often exhibit high levels of sedentary behavior that is negatively associated with cognition and mood. On the other hand, light-intensity physical activity (LIPA) may improve cognitive performance and mood. Therefore, this study investigated the acute effect of LIPA breaks during prolonged sitting on attention, executive functioning, and mood.

METHODS

A randomized crossover design was used in this study. In total, 21 healthy adults (15 women, age = 24 ± 3 years, BMI = 23 ± 2 kg/m² ) completed three prolonged sitting conditions: (1) without a demanding cognitive task (SIT), (2) with a demanding cognitive task (COGN), and (3) with every 25 min sitting interrupted by a 5-minute walk (INTERRUPT). Attention, executive function (response inhibition, task shifting, and working memory updating), and mood were assessed before and after each condition.

RESULTS

Linear mixed models analyses showed that prolonged sitting frequently interrupted by LIPA (INTERRUPT) or with cognitively demanding activities (COGN) significantly improved task shifting compared to SIT. However, INTERRUPT did not significantly improve task shifting compared with COGN. No significant acute effects on attention, response inhibition, working memory updating, or mood were found.

CONCLUSIONS

Frequent LIPA breaks or cognitively demanding activities have a selective, acute positive impact on one aspect of cognitive performance compared to idle sitting. No evidence was found that LIPA breaks have an acute improvement in attention, executive function, and mood compared to sitting with cognitive loading. To further investigate the effect of PA on cognitive performance, it is necessary to consider cognitive loading and control for the cognitive activity during sitting in the experimental design.

A Wrinkle in Measuring Time Use for Cognitive Health: How should We Measure Physical Activity, Sedentary Behaviour and Sleep?

One new case of dementia is detected every 4 seconds and no effective drug therapy exists. Effective behavioural strategies to promote healthy cognitive ageing are thus essential. Three behaviours related to cognitive health which we all engage in daily are physical activity, sedentary behaviour and sleep. These time-use activity behaviours are linked to cognitive health in a complex and dynamic relationship not yet fully elucidated. Understanding how each of these behaviours is related to each other and cognitive health will help determine the most practical and effective lifestyle strategies for promoting healthy cognitive ageing. In this review, we discuss methods and analytical approaches to best investigate how these time-use activity behaviours are related to cognitive health. We highlight four key recommendations for examining these relationships such that researchers should include measures which (1) are psychometrically appropriate; (2) can specifically answer the research question; (3) include objective and subjective estimates of the behaviour and (4) choose an analytical method for modelling the relationships of time-use activity behaviours with cognitive health which is appropriate for their research question.

Increased Prolonged Sitting in Patients with Rheumatoid Arthritis during the COVID-19 Pandemic: A Within-Subjects, Accelerometer-Based Study

BACKGROUND

Social distancing measures designed to contain the COVID-19 pandemic can restrict physical activity, a particular concern for high-risk patient groups. We assessed rheumatoid arthritis patients' physical activity and sedentary behavior level, pain, fatigue, and health-related quality of life prior to and during the social distancing measures implemented in Sao Paulo, Brazil.

METHODS

Post-menopausal females diagnosed with rheumatoid arthritis were assessed before (from March 2018 to March 2020) and during (from 24 May to 7 July 2020) social distancing measures to contain COVID-19 pandemic, using a within-subjects, repeated-measure design. Physical activity and sedentary behavior were assessed using accelerometry (ActivPAL micro). Pain, fatigue, and health-related quality of life were assessed by questionnaires.

RESULTS

Mean age was 60.9 years and BMI was 29.5 Kg/m². Disease activity ranged from remission to moderate activity. During social distancing, there were reductions in light-intensity activity (13.0% [-0.2 h/day, 95% CI: -0.4 to -0.04; p = 0.016]) and moderate-to-vigorous physical activity (38.8% [-4.5 min/day, 95% CI: -8.1 to -0.9; p = 0.015]), but not in standing time and sedentary time. However, time spent in prolonged bouts of sitting ≥30 min increased by 34% (1.0 h/day, 95% CI: 0.3 to 1.7; p = 0.006) and ≥60 min increased by 85% (1.0 h/day, 95% CI: 0.5 to 1.6). There were no changes in pain, fatigue, and health-related quality of life (all p > 0.050).

CONCLUSIONS

Imposed social distancing measures to contain the COVID-19 outbreak were associated with decreased physical activity and increased prolonged sedentary behavior, but did not change clinical symptoms sitting among patients with rheumatoid arthritis.

The Impact of the Six Pillars of Lifestyle Medicine on Brain Health

Dementia is growing exponentially worldwide. Unfortunately, the treatment available does not reverse any type of cognitive impairment. As a result, healthcare professionals are focusing on other evidence-based options, such as lifestyle medicine (LM). Current evidence demonstrates improvement in neurocognitive decline by applying the six pillars of LM, which include plant-based nutrition, physical activity, stress management, avoidance of risky substances, restorative sleep, and social connections. Plant-based nutrition has a positive impact on cognition by decreasing the risk for Alzheimer's disease (AD) with high adherence to the Mediterranean-Dietary Approach to Systolic Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND). Physical activity also might prevent neurocognitive decline by increasing fibronectin type III domain-containing protein 5 (FNDC5) and Irisin in the hippocampus, which increases energy expenditure and prolongs endurance. Additionally, higher perceived stress in adulthood and the use of risky substances such as alcohol, nicotine, and opioids are significantly associated with developing mild cognitive impairment and all-cause dementia. Furthermore, there is a positive correlation between poor sleep and social isolation with a rapid progression in cognitive decline. Lifestyle changes have a substantial impact on brain health. Therefore, the focus should always be on prevention as the primary treatment tool.

Sex Differences in Dementia

BackgroundWomen in many cohorts have a higher risk for Alzheimer's disease (AD), the most common form of dementia. Sex is a biological construct whereby differences in disease manifestation and prevalence are rooted in genetic differences between XX and XY combinations of chromosomes. This chapter focuses specifically on sex-driven differences in dementia, as opposed to differences driven by gender - a social construct referring to the societal norms that influence people's roles, relationships, and positional power throughout their lifetime.MethodsUsing a narrative review, this chapter explored the characteristics and risk factors for the dementias, alongside a discussion of sex differences including loss of sex steroid hormones in middle-aged women, differences in the prevalence of cardiovascular diseases and engagement in lifestyle protective factors for dementia.ResultsThe sex difference in AD prevalence may exist because of systematic and historic differences in risk and protective factors for dementia, including level of education obtained and socioeconomic status differences, which can impact on health and dementia risk.Levels of sex steroids decline significantly after menopause in women, whereas this is more gradual in men with age. Animal and cell culture studies show strong biological plausibility for sex steroids to protect the ageing brain against dementia. Sex steroid hormone replacement therapy has in some observational studies shown to protect against AD, but treatment studies in humans have mainly shown disappointing results. Cardiovascular disease (CVD) shares midlife medical risk (e.g. hypertension, hyperlipidaemia, obesity etc.) factors with AD and other forms of dementia, but also with related lifestyle risk - and protective factors (e.g. exercise, not smoking etc.). Men tend to die earlier of CVD, so fewer survive to develop AD at an older age. Those who do survive may have healthier lifestyles and fewer risk factors for both CVD and AD. An earlier age at menopause also confers great risk for both without hormone treatment.DiscussionIt could be the case that the decline in sex steroids around the menopause make women more susceptible to lifestyle-related risk factors associated with dementia and CVD, but this remains to be further investigated. Combining hormone treatment with lifestyle changes in midlife (e.g. exercise) could be an important preventative treatment for dementia and CVD in later life, but this also requires further research.