Associations of Objectively-Assessed Physical Activity and Sedentary Time with Hippocampal Gray Matter Volume in Children with Overweight/Obesity

A systematic review of research reporting practices in observational studies examining associations between 24-h movement behaviors and indicators of health using compositional data analysis

Background

Compositional data analysis (CoDA) techniques are well suited for examining associations between 24-h movement behaviors (i.e., sleep, sedentary behavior, physical activity) and indicators of health given they recognize these behaviors are co-dependent, representing relative parts that make up a whole day. Accordingly, CoDA techniques have seen increased adoption in the past decade, however, heterogeneity in research reporting practices may hinder efforts to synthesize and quantify these relationships via meta-analysis. This systematic review described reporting practices in studies that used CoDA techniques to investigate associations between 24-h movement behaviors and indicators of health.

Methods

A systematic search of eight databases was conducted, in addition to supplementary searches (e.g., forward/backward citations, expert consultation). Observational studies that used CoDA techniques involving log-ratio transformation of behavioral data to examine associations between time-based estimates of 24-h movement behaviors and indicators of health were included. Reporting practices were extracted and classified into seven areas: (1) methodological justification, (2) behavioral measurement and data handling strategies, (3) composition construction, (4) analytic plan, (5) composition-specific descriptive statistics, (6) model results, and (7) auxiliary information. Study quality and risk of bias were assessed by the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-sectional Studies.

Results

102 studies met our inclusion criteria. Reporting practices varied considerably across areas, with most achieving high standards in methodological justification, but inconsistent reporting across all other domains. Some items were reported in all studies (e.g., how many parts the daily composition was partitioned into), whereas others seldom reported (e.g., definition of a day: midnight-to-midnight versus wake-to-wake). Study quality and risk of bias was fair in most studies (85%).

Conclusions

Current studies generally demonstrate inconsistent reporting practices. Consistent, clear and detailed reporting practices are evidently needed moving forward as the field of time-use epidemiology aims to accurately capture and analyze movement behavior data in relation to health outcomes, facilitate comparisons across studies, and inform public health interventions and policy decisions. Achieving consensus regarding reporting recommendations is a key next step.

Supplementary Information

The online version contains supplementary material available at 10.1186/s44167-024-00062-8.

Longitudinal Relationships of Physical Activity, Sedentary Time, Cardiorespiratory Fitness, and Muscular Fitness with Body Fatness in Preschoolers

There is still insufficient knowledge about the potential benefits of physical activity and fitness or the adverse impact of sedentary behaviours on body composition at preschool age. Therefore, we aimed to study the relationships of moderate-to-vigorous physical activity (MVPA), sedentary time (ST), cardiorespiratory fitness (CRF), and muscular fitness (MF) with body fat percentage (BF%) in boys and girls. Participants were investigated twice: in the final year of kindergarten, when the boys' median age was 7 years and the girls' median age was 6 years (p = 0.240), and again in the first grade of school. MVPA and ST were measured with an accelerometer, BF% was derived from skinfold thicknesses, CRF was measured with a 20 m shuttle run test, and MF was represented by the mean z-scores from standing long jump and relative upper-limb strength. In girls, higher ST (β = 0.587, p = 0.021) and lower MF (β = -0.231, p = 0.009) at preschool age were related to higher BF% in the first grade of school after adjustment for confounders. MVPA and CRF in preschool children were unrelated to BF% in school among boys and girls. In conclusion, sitting less and having greater muscular fitness at preschool age appear to be beneficial for lower body fatness in the first grade among girls, but not in boys. MVPA and CRF at preschool age are unrelated to body fatness at school age in boys and girls. Our results indicate that girls may especially benefit from decreasing sedentary behaviours and increasing upper- and lower-limb muscular strength at preschool age for a healthy weight profile in the first grade of school.

Neurosustainability

While the human brain has evolved extraordinary abilities to dominate nature, modern living has paradoxically trapped it in a contemporary "cage" that stifles neuroplasticity. Within this modern environment lurk unseen natural laws with power to sustain the human brain's adaptive capacities - if consciously orchestrated into the environments we design. For too long our contemporary environments have imposed an unyielding static state, while still neglecting the brain's constant adaptive nature as it evolves to dominate the natural world with increasing sophistication. The theory introduced in this article aims to go back in nature without having to go back in time, introducing and expounding Neurosustainability as a novel paradigm seeing beyond the contemporary confines to architect environments and brains in parallel. Its integrated neuro-evidenced framework proposes four enrichment scopes-spatial, natural, aesthetic, and social-each holding multifaceted attributes promising to sustain regions like the hippocampus, cortex and amygdala. Neurosustainability aims to liberate the quintessential essence of nature to sustain and enhance neuroplastic processes through a cycle that begins with design and extends through epigenetic changes. This paradigm shift aims to foster cognitive health and wellness by addressing issues like stress, depression, anxiety and cognitive decline common in the contemporary era thereby offering a path toward a more neurosustainable era aiming to nurture the evolution of the human brain now and beyond.

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.

Which indices of cardiorespiratory fitness are more strongly associated with brain health in children with overweight/obesity?

PURPOSE

To compare the strength of associations between different indices of cardiorespiratory fitness (CRF) and brain health outcomes in children with overweight/obesity.

METHODS

Participants were 100 children aged 8-11 years. CRF was assessed using treadmill exercise test (peak oxygen uptake [V̇O2peak ], treadmill time, and V̇O2 at ventilatory threshold) and 20-metre shuttle run test (20mSRT, laps, running speed, estimated V̇O2peak using the equations by Léger et al., Mahar et al., and Matsuzaka et al.). Intelligence, executive functions, and academic performance were assessed using validated methods. Total gray matter and hippocampal volumes were assessed using structural MRI.

RESULTS

V̇O2peak /body mass (β = 0.18, 95% CI = 0.01-0.35) and treadmill time (β = 0.18-0.21, 95% CI = 0.01-0.39) were positively associated with gray matter volume. 20mSRT laps were positively associated with executive functions (β = 0.255, 95% CI = 0.089-0.421) and academic performance (β = 0.199-0.255, 95% CI = 0.006-0.421), and the running speed was positively associated with executive functions (β = 0.203, 95% CI = 0.039-0.367). Estimated V̇O2peak/Léger et al. was positively associated with intelligence, executive functions, academic performance, and gray matter volume (β = 0.205-0.282, 95% CI = 0.013-0.500). Estimated V̇O2peak/Mahar et al. and V̇O2peak/Matsuzaka et al. (speed) were positively associated with executive functions (β = 0.204-0.256, 95% CI = 0.031-0.436).

CONCLUSION

Although V̇O2peak is considered the gold standard indicator of CRF in children, peak performance (laps or running speed) and estimated V̇O2peak/Léger et al. derived from 20mSRT had stronger and more consistent associations with brain health outcomes than other indices of CRF in children with overweight/obesity.

Prenatal Exposure to Gestational Diabetes Mellitus is Associated with Mental Health Outcomes and Physical Activity has a Modifying Role

Background

Studies suggest a link between prenatal gestational diabetes mellitus (GDM) exposure and poor mental health outcomes. We examined associations between prenatal GDM exposure and depressive and anxiety symptoms in children and assessed physical activity as a potential modifier of these associations.

Method

Seventy children (AgeM(SD): 12(2.0), 56% GDM, 59% female) and their parents completed surveys: Center for Epidemiological Studies Depression Scale for Children (CES-DC), State-Trait Anxiety Inventory for Children (STAIC), Child Behavior Checklist (CBCL), and 3-day physical activity recall (3DPAR). Associations between mental health measures with GDM exposure and interactions between GDM exposure and child moderate-to-vigorous physical activity (MVPA) were assessed using regression.

Results

GDM-exposed children had higher anxiety (p = 0.03) and internalizing symptoms (CBCL) (p = 0.04) than unexposed children. There was an interaction between GDM exposure and child MVPA on anxiety (p = 0.02), internalizing (p = 0.04) and externalizing symptoms (p = 0.004). In the low MVPA group, GDM exposed children had more depressive (p = 0.03), anxiety (p = 0.003), and internalizing symptoms (p = 0.03) than unexposed children. In the high MVPA group, there were no group differences except with externalizing symptoms (p = 0.04).

Conclusion

Prenatal GDM is associated with higher anxiety and internalizing symptoms in children. Child MVPA modified the relationship between GDM exposure and mental health outcomes suggesting that physical activity during childhood could mitigate the negative mental health outcomes associated with prenatal GDM exposure.

Physical activity, sedentary time, and fitness in relation to brain shapes in children with overweight/obesity: Links to intelligence

OBJECTIVES

To examine the association between physical activity, sedentary time, and physical fitness with the shapes of subcortical brain structures in children with overweight/obesity. Further, we analyzed whether differences in the shapes of subcortical brain structures were related to intelligence. We hypothesized that those children with higher physical activity levels, lower sedentary time, and better fitness, would show greater expansion of the brain regions analyzed, and these expansions would be associated with higher intelligence.

STUDY DESIGN

100 children (10.0 ± 1.1 years, 40 girls) were included in the analyses. Physical activity and sedentary time were measured by accelerometry, and physical fitness was evaluated by a fitness battery. Shapes of subcortical brain structures were assessed by magnetic resonance imaging. Intelligence was measured by the Kaufmann Brief Intelligence test.

RESULTS

Physical activity was related to expansion of the right/left pallidum, right/left putamen, and right thalamus (p < 0.05). Higher sedentary time was related to contraction of the left thalamus and right nucleus accumbens (p < 0.05). Higher levels of cardiorespiratory fitness were associated with expansion of the right amygdala (p = 0.022). Greater strength in the upper-limb was related to expansion of the right/left pallidum and the left nucleus accumbens (p < 0.038), and contraction of the left amygdala (p = 0.030). Better speed-agility was associated with expansion of the left nucleus accumbens (p = 0.036). Physical activity- and fitness-related expansion of the right pallidum was associated with higher intelligence (all p < 0.05).

CONCLUSION

Physical activity, sedentary time, and physical fitness were significantly related to the shapes of subcortical brain structures, which in turn were related to intelligence in children with overweight/obesity.

The influential factors and non-pharmacological interventions of cognitive impairment in children with ischemic stroke

Background

The prevalence of pediatric ischemic stroke rose by 35% between 1990 and 2013. Affected patients can experience the gradual onset of cognitive impairment in the form of impaired language, memory, intelligence, attention, and processing speed, which affect 20-50% of these patients. Only few evidence-based treatments are available due to significant heterogeneity in age, pathological characteristics, and the combined epilepsy status of the affected children.

Methods

We searched the literature published by Web of Science, Scopus, and PubMed, which researched non-pharmacological rehabilitation interventions for cognitive impairment following pediatric ischemic stroke. The search period is from the establishment of the database to January 2022.

Results

The incidence of such impairment is influenced by patient age, pathological characteristics, combined epilepsy status, and environmental factors. Non-pharmacological treatments for cognitive impairment that have been explored to date mainly include exercise training, psychological intervention, neuromodulation strategies, computer-assisted cognitive training, brain-computer interfaces (BCI), virtual reality, music therapy, and acupuncture. In childhood stroke, the only interventions that can be retrieved are psychological intervention and neuromodulation strategies.

Conclusion

However, evidence regarding the efficacy of these interventions is relatively weak. In future studies, the active application of a variety of interventions to improve pediatric cognitive function will be necessary, and neuroimaging and electrophysiological measurement techniques will be of great value in this context. Larger multi-center prospective longitudinal studies are also required to offer more accurate evidence-based guidance for the treatment of patients with pediatric stroke.

Motor skills and cognitive benefits in children and adolescents: Relationship, mechanism and perspectives

OBJECTIVE

There is a strong interaction between motor skills and cognitive benefits for children and young people. The aim of this paper is to explore the relationship between motor skill types and their development and the cognitive benefits of children and adolescents. In turn, on this basis, it proposes pathways and mechanisms by which motor skills improve cognition, and provide a basis for subsequent teaching of skills that follow the laws of brain cognitive development.

METHODS

This paper summarizes the research on the relationship between different types of motor skills and their development and cognitive benefits of children and adolescents. Based on these relationships, pathways, and mechanisms for motor skills to improve cognition are tentatively proposed.

RESULTS

There is an overall pattern of "open > closed, strategy > interception, sequence > continuous" between motor skill types and the cognitive benefits of children and adolescents. Long-term motor skill learning practice is accompanied by increased cognitive benefits as skill proficiency increases. The dynamic interaction between motor skills and physical activity exposes children and adolescents to environmental stimuli and interpersonal interactions of varying complexity, promoting the development of agility, coordination and cardiorespiratory fitness, enhancing their motor experience, which in turn improves brain structure and functional activity.

CONCLUSION

Motor skills training promote cognitive efficiency in children and adolescents. Motor skill interventions that are open-ended, strategic and sequential in nature are more effective. Environmental stimuli, interpersonal interaction, agility, coordination, and cardiorespiratory fitness can be considered as skill attribute moderators of motor skills to improve cognition.

Effects of reducing sedentary behaviour duration by increasing physical activity, on cognitive function, brain function and structure across the lifespan: a systematic review protocol

INTRODUCTION

Greater engagement in sedentary behaviours has been related to poorer cognitive functions in epidemiological research. However, the effects of reducing sedentary behaviour duration on cognitive function, brain function, and structure remain poorly understood. This systematic review aims to synthesise the evidence on the effects of reducing sedentary behaviour duration by increasing time spent in physical activity on cognitive function, brain structure and function in apparently healthy children, adolescents and adults.

METHODS AND ANALYSIS

The protocol follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The literature search will be conducted (search dates: August-September 2022) across six databases: PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (via EBSCO Host), PsycINFO (via ProQuest), SPORTDiscus and Web of Science (Science and Social Science Citation Index). The inclusion criteria are as follows: randomised and non-randomised experimental studies as defined by the Cochrane Handbook, published in English, in peer-reviewed journals, and as theses or dissertations. References of included papers will be screened for additional studies. Acute and chronic interventions targeting children (≥ 4 years), adolescents, younger adults (≥ 18-40 years), middle-aged (40-64 years) and older adults (65+ years) will be eligible. Methodological quality will be assessed with the Effective Public Health Practice Project quality assessment tool for quantitative studies. Qualitative synthesis will be stratified by intervention type (acute vs chronic), intervention content (reducing sedentary time or interrupting prolonged sitting) and outcome (cognitive, brain structure and function).

ETHICS AND DISSEMINATION

No primary data collection will be conducted as part of this systematic review. Study findings will be disseminated through peer-reviewed publications, conference presentations and social media.

PROSPERO REGISTRATION NUMBER

CRD42020200998.

Physical activity and exercise alter cognitive abilities, and brain structure and activity in obese children

The prevalence of childhood obesity is increasing to such an extent that it has become a major global public health problem in the 21st century. Obesity alters children’s brain structure and activity and impairs their cognitive abilities. On the basis of these findings, it is necessary for educational and healthcare institutions to combat childhood obesity through preventive and therapeutic strategies. In general, exercise and physical activity are considered common but effective methods for improving physical, psychological, and brain health across the life span. Therefore, this review article mainly focuses on existing neuroimaging studies that have used magnetic resonance imaging (MRI), and functional magnetic resonance imaging (fMRI)to assess children’s brain anatomy and neural activity. We intended to explore the roles of physical activity and exercise in modulating the associations among childhood obesity, cognitive abilities, and the structure and activity of the brain.

Assessment of executive functions and physical activity in girls and boys with normal weight, overweight and obesity

OBJECTIVE

To evaluate the association between body mass index (BMI) and performance of executive functions (EFs) in girls and boys with 9- and 10-year-old schoolchildren with moderate- to vigorous-intensity physical activity (MVPA) and sedentary behaviour.

METHODS

A total of 120 schoolchildren (61 girls and 59 boys) were evaluated anthropometrically. The MVPA was evaluated with a self-report questionnaire. EFs were measured using a neuropsychological battery of Executive Functions and Frontal Lobes-2 (BANFE-2).

RESULTS

A high BMI was associated with longer delay in completing inhibitory control tests (p = 0.00, r_p  = 0.32) and working memory (p = 0.00, r_p  = 0.26). We observed correlations in time (p = 0.00, r_p  = -0.43) and hits (p = 0.04, r_p  = -0.27) of self-directed signalling test in boys; and girls in alphabetical words order (p = 0.00, r_p  = -0.39). Active normal weight schoolchildren (ANw) performed better by successfully completed the working memory tasks (H = 26.97, p = 0.00) than sedentary schoolchildren with overweight and obesity. In addition, overweight-active schoolchildren (AOw) showed better performance on working memory tests in time (p = 0.00) and hits (p = 0.01) than their sedentary peers. Multiple linear regression analysis revealed a significant association between BMI and EFs scores (F = 2.41, df = 98, p = 0.001).

CONCLUSIONS

EFs are affected by a high BMI and sedentary behaviour in school children. Boys and girls reflected differences to solve the same challenges. The MVPA has a positive effect on executive control skills mainly in overweight children.

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

Although sleep, physical activity and sedentary behavior have been found to be associated with dementia risk, findings are inconsistent and their joint relationship remains unclear. This study aimed to investigate independent and joint associations of these three modifiable behaviors with dementia risks. A total of 431,924 participants (median follow-up 9.0 years) without dementia from UK Biobank were included. Multiple Cox regressions were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Models fitted with restricted cubic spline were conducted to test for linear and nonlinear shapes of each association. Sleep duration, leisure-time physical activity (LTPA), and screen-based sedentary behavior individually associated with dementia risks in different non-linear patterns. Sleep duration associated with dementia in a U-shape with a nadir at 7 h/day. LTPA revealed a curvilinear relationship with dementia in diminishing tendency, while sedentary behavior revealed a J-shaped relationship. The dementia risk was 17% lower in the high LTPA group (HR[95%CI]: 0.83[0.76-0.91]) and 22% higher in the high sedentary behavior group (1.22[1.10-1.35]) compared to the corresponding low-level group, respectively. A combination of seven-hour/day sleep, moderate-to-high LTPA, and low-to-moderate sedentary behavior showed the lowest dementia risk (0.59[0.50-0.69]) compared to the referent group (longer or shorter sleep/low LTPA/high sedentary behavior). Notably, each behavior was non-linearly associated with brain structures in a pattern similar to its association with dementia, suggesting they may affect dementia risk by affecting brain structures. Our findings highlight the potential to change these three daily behaviors individually and simultaneously to reduce the risk of dementia.

Promoting brain health through physical activity among adults exposed to early life adversity: Potential mechanisms and theoretical framework

Adverse childhood experiences such as abuse, neglect, and poverty, profoundly alter neurobehavioral development in a manner that negatively impacts health across the lifespan. Adults who have been exposed to such adversities exhibit premature and more severe age-related declines in brain health. Unfortunately, it remains unclear whether the negative effects of early life adversity (ELA) on brain health can be remediated through intervention in adulthood. Physical activity may represent a low-cost behavioral approach to address the long-term consequences of ELA on brain health. However, there has been limited research examining the impact of physical activity on brain health among adults with a history of ELA. Accordingly, the purpose of this review is to (1) review the influence of ELA on brain health in adulthood and (2) highlight evidence for the role of neurotrophic factors, hypothalamic-adrenal-pituitary axis regulation, inflammatory processes, and epigenetic modifications in mediating the effects of both ELA and physical activity on brain health outcomes in adulthood. We then propose a theoretical framework to guide future research in this area.

Physical Activity, Fitness, and Cognitive Performance of Estonian First-Grade Schoolchildren According Their MVPA Level in Kindergarten: A Longitudinal Study

Little is known about the longitudinal trajectories and associations regarding physical activity (PA), physical fitness (PF), and cognitive skills in childhood. Accelerometer-based PA, sedentary behavior (SB), PF, and cognitive skills were measured in Estonian children (n = 147) in kindergarten (6.6 years) and again at school (7.6 years). Children were subgrouped into lower and upper quartiles by their moderate-to-vigorous PA (MVPA) at 6.6 years. Children in the upper quartile had lower SB, higher PA, and greater muscular strength. Attending school, MVPA in the lower quartile improved. In both subgroups, most strength values and cognitive skills improved, while balance deteriorated in first grade. In the upper quartile, a greater MPA at 6.6 years predicted lower perceptual skills at 7.6 years. A greater SB at 6.6 years predicted higher verbal skills, light and moderate PA and MVPA, and lower verbal skills at 7.6 years after taking into account confounding factors such as the child's sex, age, awake wear time (AWT), maternal education, and/or child's sports participation. A vigorous PA at 6.6 years predicted perceptual (in upper quartile) or verbal (in lower quartile) skills at 7.6 years after controlling for similar confounders. No correlation for PF at 6.6 years and cognitive skills at 7.6 years existed; after adjusting for the above-mentioned confounders relative to upper/lower-limb strength, the 4 × 10 m shuttle run results predicted higher perceptual or verbal skills; static balance and cardiorespiratory fitness predicted lower verbal skills. Cardiorespiratory fitness predicted higher perceptual skills after controlling for sex, age, and AWT. Overall, PA and strength were constantly better and SB lower in the upper quartile, yet the lower quartile demonstrated improved MVPA in first grade, and both subgroups increased most components of their strength and cognitive skills in first grade. Higher levels of VPA at kindergarten predicted either better perceptual or verbal skills in first grade after controlling for confounders; the opposite associations were found for other PA levels and cognitive skills in the higher quartile. PF components at kindergarten predicted either superior or inferior cognitive skills in first grade after adjusting for confounders.

The Impact of an 8-Weeks At-Home Physical Activity Plan on Academic Achievement at the Time of COVID-19 Lock-Down in Italian School

The purpose of this randomized controlled study was to investigate the efficacy of an 8-week exercise programme conducted in e-learning mode on high school students’ academic performance. The aim was to examine the changes in physical fitness and learning outcomes during the enforced period of lockdown caused by outbreak of the second wave of COVID-19 pandemic and the closure of schools in Italy. Thirty high-school students (14–15 years) were randomly assigned to an experimental group (n = 15) that performed an at-home workout programme (~60 min., twice a week), or a control group (n = 15) who received only a regular programme of theoretical lessons where no practice takes place. Both groups were synchronized in real-time with the physical education teacher. In order to assess students’ starting level and significant changes reached, at baseline and after training, a battery of standardized assessment motor tests (Standing long jump test, Harvard step test, sit and reach test, and butt kicks test), and an academic achievement test (Amos 8–15) were administered. In comparison to the control group at baseline and the end of the programme, the experimental group reported considerable improvements in motivation and concentration, significant anxiety reduction, and an increase in capacity to organize studying and to be more flexible. Moreover, it was possible to observe the efficacy of the workout to improve learning ability among practicing students (p < 0.001). No significant changes were found in the control group. The results suggest that a school-based exercise programme conducted online could be a powerful approach in order to achieve the best academic outcomes and for improving students’ physical fitness as well as their cognitive health.

Preschool physical activity and fitness predicts conceptual, verbal and perceptual skills at school

This study investigated longitudinal relationships between physical activity (PA), fitness and cognitive performance at early years. In total, 147 children at the age of 6.6 and 7.6 years participated in the study. PA and sedentary behaviour (SB) were registered with accelerometer. Skinfold thickness measurements were used to assess body composition. Children's cardiorespiratory fitness (CRF), muscular strength and speed-agility fitness was assessed using PREFIT fitness test battery and static balance by EUROFIT test battery. Cognitive skills were measured with modified Boehm-3 test. Linear regression analyses showed that PA at the age of 6.6 years was positively, while SB was negatively associated with the conceptual skills at the age of 7.6 years after adjusting for confounders. Positive associations were observed between CRF, lower-limbs strength relative to fat-free mass, static balance at the age of 6.6 years with perceptual skills at 7.6 years in unadjusted analysis. PA and fitness were not associated with verbal abilities. Physically active lifestyle and CRF, relative explosive strength of the lower limbs, balance at 6.6 years in kindergarten predict conceptual and perceptual skills, but does not predict verbal abilities 1 year later at first grade in school. SB affects negatively conceptual skills.

Objectively measured intensity-specific physical activity and hippocampal volume among community-dwelling older adults

Background

The hippocampus is a brain structure important for memory and cognitive function. Physical activity may help prevent hippocampal atrophy. However, few studies have measured sedentary behavior (SB) and intensity-specific physical activity using an accelerometer. This study aimed to examine the cross-sectional associations of objectively-determined SB, light-intensity physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) measured by an accelerometer with hippocampal volume among community-dwelling older adults using compositional data analysis (CoDa) approach.

Methods

This cross-sectional study was part of the Neuron to Environmental Impact across Generations (NEIGE) study. A randomly recruited sample of 485 Japanese older adults (47% male; aged 65–84 years) wore tri-axial accelerometers (Omron Healthcare) for 7 consecutive days in 2017. Hippocampal volume was measured with magnetic resonance imaging and the left and right hippocampal volumes were automatically segmented using FreeSurfer software. Associations of sedentary and physically active behaviors with hippocampal volume were examined with compositional linear regression analysis based on isometric log-ratio transformations of time use adjusted for potential confounding factors.

Results

The relative proportion of time spent in MVPA, compared to the other two activities, was significantly positively associated with right hippocampal volume (β: 57.1, P-value = 0.027). However, no association existed between higher proportions of MVPA and left hippocampal volume, or between proportions of SB or LPA with either left or right hippocampal volumes.

Conclusion

The proportion of time spent in MVPA, relative to the other two activities, was significantly positively associated with right hippocampal volume. MVPA may be beneficial for maintaining hippocampal volume.

Activity-rest circadian pattern and academic achievement, executive function, and intelligence in children with obesity

This study aimed to analyze the associations of activity-rest pattern indicators with academic achievement, executive function, and intelligence and to explore whether these associations are mediated by the total gray matter volume among children with overweight/obesity. Ninety-five children (10 ± 1 year, 37 girls) with overweight/obesity (based on the World Obesity Federation body mass index cutoff points) were included in this cross-sectional study. Hip- and wrist-worn ActiGraph GT3X + accelerometers were used to assess the activity-rest pattern. Interdaily stability (IS), intradaily variability (IV), the mean value of the lowest 5 hours (L5), and the mean value of the maximum 10 hours (M10) of activity and their respective timing (TL5, TM10) were used as indicators of the activity-rest pattern throughout the day. Chronotype and social jetlag were used as indicators of circadian preference. Academic achievement, executive function, and intelligence were assessed with standardized tests. Gray matter volume was acquired by magnetic resonance imaging (MRI). IS was positively associated with executive function (β = 0.244, P = .014). IV was negatively associated with mathematics and academic applications (β: -0.211 to -0.238, P's ≤ .026). Later TM10 in the day was related to lower writing, academic skills, and intelligence (β: -0.229 to -0.271, P's ≤ .025). None of the associations found were mediated by gray matter volume. A non-fragmented and stable activity-rest pattern and earlier physical activity in the day were associated with better academic achievement, executive function, and intelligence in children with overweight/obesity. Further studies are required to corroborate or contrast our findings.

Associations between physical activity, body composition, and physical fitness in the transition from preschool to school

The purpose of the study was to assess the longitudinal associations of physical activity (PA) with body composition and physical fitness (PF) at the 12-month follow-up during the transition from kindergarten to school in Estonian children aged 6 to 8 years (n = 147). PA and sedentary behavior (SB) were assessed using the accelerometer. Body composition was measured from triceps and subscapular skinfold thicknesses and PF using PREFIT test battery. SB at the mean age of 6.6 year had negative relation with upper and lower body strength and motor fitness at the mean age of 7.6 year in adjusted models. Light PA (LPA) and moderate PA(MPA) at 6.6 year were positively and SB was negatively associated with fat-free mass index (FFMI) at 7.6 year after adjustments for confounders [vigorous PA (VPA), total awake wear time, child's sex, age at measurement]. Substituting 5 min/d of SB at 6.6 year with 5 min of VPA was related to higher FFMI at 7.6 year. In adjusted models, VPA at 6.6 year was positively associated with cardiorespiratory fitness at 7.6 year, greater baseline VPA or moderate-to-vigorous PA (MVPA) predicted greater upper body strength a year later and LPA, MPA, VPA, MVPA at 6.6 year were positively related to lower body strength at follow-up. In adjusted analysis greater VPA at 6.6 year was related to better motor fitness at follow-up. Promoting higher-intensity PA and reducing SB at preschool may have long-term effects on body composition and PF in children at the first grade.