Compositional analyses of the associations between sedentary time, different intensities of physical activity, and cardiometabolic biomarkers among children and youth from the United States

Introduction : Compositional data analysis is one appropriate method for co-dependent data, even when data are collected for a subdivision of the 24-hour period, such as the waking day. Objectives were to use compositional analyses to examine the combined and relative associations of sedentary time (ST), light-intensity physical activity (LPA), moderate-intensity physical activity (MPA), and vigorous-intensity physical activity (VPA) with cardiometabolic biomarkers in a representative sample of children and youth. Methods : This cross-sectional study included 2544 participants aged 6-17 years from the 2003-2006 United States National Health and Nutrition Examination Survey. ST (= 7 METs) were accelerometer-derived. Cardiometabolic biomarkers included waist circumference, body mass index (BMI) z-score, HDL-cholesterol, C-reactive protein, and blood pressure. Triglycerides, glucose, insulin, and LDL-cholesterol were measured in a fasting sub-sample of adolescents (n = 670). Compositional linear regression models were conducted. Results : The composition of ST, LPA, MPA, and VPA was significantly associated with BMI z-score, log waist circumference, systolic and diastolic blood pressure, HDL-cholesterol, and log plasma glucose (variance explained: 1-29%). Relative to the other three behaviors, VPA was negatively associated with BMI z-score (gamma VPA = -0.206, p = 0.005) and waist circumference (gamma VPA = -0.03, p = 0.001). Conversely, ST was positively associated with waist circumference (gamma ST = 0.029, p = 0.013). ST and VPA were also positively associated with diastolic blood pressure (gamma ST = 2.700, p = 0.018; gamma VPA = 1.246, p = 0.038), relative to the other behaviors, whereas negative associations were observed for LPA (gamma LPA = -2.892, p = 0.026). Finally, VPA was positively associated with HDL-cholesterol, relative to other behaviors (gamma VPA = 0.058, p<0.001). Conclusions : The ST and physical activity composition appears important for many aspects of cardiometabolic health in children and youth. Compositions with more time in higher-intensity activities may be better for some aspects of cardiometabolic health

Proportion of children meeting recommendations for 24-hour movement guidelines and associations with adiposity in a 12-country study

BACKGROUND: The Canadian 24-h movement guidelines were developed with the hope of improving health and future health outcomes in children and youth. The purpose of this study was to evaluate adherence to the 3 recommendations most strongly associated with health outcomes in new 24-h movement guidelines and their relationship with adiposity (obesity and body mass index z-score) across countries participating in the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE).METHODS: Cross-sectional results were based on 6128 children aged 9-11 years from the 12 countries of ISCOLE. Sleep duration and moderate-to-vigorous physical activity (MVPA) were assessed using accelerometry. Screen time was measured through self-report. Body weight and height were measured. Body mass index (BMI, kg · m(-2)) was calculated, and BMI z-scores were computed using age- and sex-specific reference data from the World Health Organization. Obesity was defined as a BMI z-score &gt; +2 SD. Meeting the overall 24-h movement guidelines was defined as: 9 to 11 h/night of sleep, ≤2 h/day of screen time, and at least 60 min/day of MVPA. Age, sex, highest parental education and unhealthy diet pattern score were included as covariates in statistical models. Associations between meeting vs. not meeting each single recommendation (and combinations) with obesity were assessed with odds ratios calculated using generalized linear mixed models. A linear mixed model was used to examine the differences in BMI z-scores between children meeting vs. not meeting the different combinations of recommendations.RESULTS: The global prevalence of children meeting the overall recommendations (all three behaviors) was 7%, with children from Australia and Canada showing the highest adherence (15%). Children meeting the three recommendations had lower odds ratios for obesity compared to those meeting none of the recommendations (OR = 0.28, 95% CI 0.18-0.45). Compared to not meeting the 24-h movement recommendations either independently or combined, meeting them was significantly associated with a lower BMI z-score. Whenever the MVPA recommendation was included in the analysis the odds ratios for obesity were lower.CONCLUSIONS: For ISCOLE participants meeting these 3 healthy movement recommendations the odds ratios of being obese or having high BMI z-scores were lower. However, only a small percentage of children met all recommendations. Future efforts should aim to find promising ways to increase daily physical activity, reduce screen time, and ensure an adequate night's sleep in children.TRIAL REGISTRATION: The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) was registered at ClinicalTrials.gov (Identifier NCT01722500) (October 29, 2012).</p

Eating behavior traits and sleep as determinants of weight loss in overweight and obese adults

Objective: To examine the associations between eating behavior traits and weight loss according to sleep quality and duration in adults enrolled in common weight-loss interventions. Methods: Participants included overweight and obese men and women (n=150) (mean±s.d. age, 38.8±8.6 years; mean±s.d. body mass index (BMI), 33.3±3.5 kg m−2) who were subjected to a dietary intervention over a period of 12–16 weeks. Anthropometric measurements, eating behavior traits (Three-Factor Eating Questionnaire), sleep quality (total Pittsburgh Sleep Quality Index (PSQI) score) and sleep duration (hours per night, self-reported from the PSQI) were assessed at both baseline and post intervention. Linear regression analysis was used to quantify the relationships between eating behavior traits and changes in anthropometric markers for all subjects and by sleep categories (short sleep: <7 h per night vs recommended sleep: greater than or equal to7 h per night; poor sleep quality: greater than or equal to5 PSQI score vs good sleep quality: <5 PSQI score). We adjusted for age, sex and baseline BMI in analyses. Results: Baseline eating behavior traits were modest predictors of weight-loss success, but they were all significantly associated with their changes over the weight-loss intervention (P<0.01). The diet intervention induced significant changes in eating behavior traits and even more for those having a non-favorable eating behavior profile at baseline. We observed that changes in flexible control and strategic dieting behavior were constantly negatively associated with changes in body weight and fat mass (P<0.05) for recommended duration sleepers. The change in situational susceptibility to disinhibition was positively associated with the change in fat mass and body weight for those having healthy sleeping habits (P<0.05). For poor quality sleepers, the change in avoidance of fattening foods was negatively associated with changes in adiposity (P<0.05). Conclusion: Eating behavior traits and sleep may act together to influence the outcome of weight-loss programs

Cross-sectional associations between sleep duration, sedentary time, physical activity, and adiposity indicators among Canadian preschool-aged children using compositional analyses

Abstract Background Sleep duration, sedentary behaviour, and physical activity are three co-dependent behaviours that fall on the movement/non-movement intensity continuum. Compositional data analyses provide an appropriate method for analyzing the association between co-dependent movement behaviour data and health indicators. The objectives of this study were to examine: (1) the combined associations of the composition of time spent in sleep, sedentary behaviour, light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) with adiposity indicators; and (2) the association of the time spent in sleep, sedentary behaviour, LPA, or MVPA with adiposity indicators relative to the time spent in the other behaviours in a representative sample of Canadian preschool-aged children. Methods Participants were 552 children aged 3 to 4 years from cycles 2 and 3 of the Canadian Health Measures Survey. Sedentary time, LPA, and MVPA were measured with Actical accelerometers (Philips Respironics, Bend, OR USA), and sleep duration was parental reported. Adiposity indicators included waist circumference (WC) and body mass index (BMI) z-scores based on World Health Organization growth standards. Compositional data analyses were used to examine the cross-sectional associations. Results The composition of movement behaviours was significantly associated with BMI z-scores (p = 0.006) but not with WC (p = 0.718). Further, the time spent in sleep (BMI z-score: γ sleep  = −0.72; p = 0.138; WC: γ sleep  = −1.95; p = 0.285), sedentary behaviour (BMI z-score: γ SB  = 0.19; p = 0.624; WC: γ SB  = 0.87; p = 0.614), LPA (BMI z-score: γ LPA  = 0.62; p = 0.213, WC: γ LPA  = 0.23; p = 0.902), or MVPA (BMI z-score: γ MVPA  = −0.09; p = 0.733, WC: γ MVPA  = 0.08; p = 0.288) relative to the other behaviours was not significantly associated with the adiposity indicators. Conclusions This study is the first to use compositional analyses when examining associations of co-dependent sleep duration, sedentary time, and physical activity behaviours with adiposity indicators in preschool-aged children. The overall composition of movement behaviours appears important for healthy BMI z-scores in preschool-aged children. Future research is needed to determine the optimal movement behaviour composition that should be promoted in this age group

Influence of Perceived Stressful Homework on Lifestyle Habits and Subsequently on Adiposity : a QUALITY Study

Contexte : Les devoirs perçus stressants semblent avoir un effet négatif sur l’adiposité des enfants entre 8-10 ans et l’activité physique d’intensité moyenne-élevée (APMV) et le temps-écran sont des médiateurs dans cette relation. Objectifs : 1) Examiner si un facteur nutritionnel pourrait aussi être un médiateur, 2) Étudier les associations et médiateurs présents à l’âge de 10-12 ans, et 3) Prendre une approche longitudinale sur ces résultats pour étudier ces relations. Méthodes : Les données suivantes de l’étude de QUALITY ont été extraites : durée des devoirs, niveau de stresse et temps-écran, durée de sommeil et APMV, facteurs nutritionnels, et profil d’adiposité. « Process Macro » a été utilisé pour faire les analyses statistiques. Résultats principaux : Les devoirs perçus étant stressants étaient positivement associés avec l’adiposité seulement à 8-10 ans chez les enfants, particulièrement les filles. La consommation de breuvage sucré était un médiateur partiel entre les devoirs perçus étant stressants et le pourcentage de gras abdominal des enfants de 8-10 ans. À 10-12 ans, le temps-écran était le seul médiateur entre les devoirs et l’index de masse corporelle. Le changement dans la durée de sommeil était le seul médiateur entre les changements de devoirs perçus étant stressant et pourcentage de gras abdominal qui s’est produit depuis l’âge de 8-10 ans chez les enfants, particulièrement les filles. Conclusions : Avec l’avancée de l’âge et augmentation des devoirs, les habitudes d’écran changent. Dans l’aspect préventif de l’obésité pédiatrique, le temps-écran et la durée de sommeil pourraient être surveillés de près.Background: Perceived stressful homework was shown to be associated with poor adiposity profile in children aged 8-10 years old, and this was mediated by a decrease in moderate-to-vigorous physical activity (MVPA) and an increase in screen time. Objectives: 1) Explore if any dietary factors could be potential mediator, 2) Observe the associations and mediators present at 10-12 years of age, and 3) Examine from a longitudinal perspective these associations (from 8-10 years old to 10-12 years old). Methods: The following information on the QUALITY cohort children were extracted: homework duration, stress level and screen time, sleep and MVPA duration, dietary factors, and adiposity profile. Process Macro for SPSS was used for the statistical analysis. Main Results: Perceived stressful homework was positively associated with adiposity at 8-10 years old only in all children, particularly in girls. High-sugar drink was a partial mediator between perceived stressful homework and trunk fat percentage in children at 8-10 years old. Screen time mediated the relationship between homework and body mass index of children at 10-12 years old. Sleep duration change mediated the association between perceived stressful homework duration and trunk fat percentage changes in children since ages 8-10 years old, especially in girls. Discussion: As children grow and perform a lot of homework, screen habits changes. In prevention aspect of paediatric obesity, screen time and sleep duration are the two major habits to monitor

Mental work stimulates cardiovascular responses through a reduction in cardiac parasympathetic modulation in men and women

Mental Work (MW) stimulates Cardiovascular (CV) functions in healthy adults and a reduction in cardiac parasympathetic modulation could be one mechanism involved in such a response. The influence of sex on these CV responses remains ambiguous. The aim of the study was to evaluate CV impacts of MW in healthy individuals and whether sex influences CV responses induced by MW. The impact of a 45-min reading and writing session vs. a control condition, on Blood Pressure (BP), Heart Rate (HR), and Heart Rate Variability (HRV), was evaluated in 44 healthy adults with the use of a randomized crossover design. The influence of sex on those variables was then evaluated. Diastolic BP (74 ± 1 vs. 69 ± 1 mmHg; p < 0.05) and mean arterial pressure (MAP; 87 ± 7 vs. 83 ± 8 mmHg; p < 0.005), HR (68 ± 1 vs. 62 ± 1 bpm; p < 0.0001) and low frequency/high frequency ratio (2.8 ± 0.1 vs. 2.0 ± 0.1; p < 0.0001) were higher, while global HRV (SDNN: 84 ± 3 vs.104 ± 3 ms; p < 0.0001) and cardiac parasympathetic activity were lower during MW (p < 0.0001) vs. the control condition in the whole sample. During both experimental conditions, HR was higher (p < 0.0001), while BP, rMSSD, pNN50 and low frequency component of HRV were lower in women compared to men (all p < 0.05). The intensity of the cognitive demand and its influence on CV variables were comparable between men and women. These results support that MW increases BP and HR through decrement in cardiac parasympathetic modulation in healthy subjects and suggest that sex does not influence CV responses induced by cognitive demand of similar intensity

Understanding 24-hour movement behaviours and their associations with children’s psychosocial health during the transition from primary to secondary school

Background The transition from primary to secondary school is one of the life transition periods during which significant behavioural changes may occur. However, there is little evidence on concurrent changes in sleep, sedentary behaviour and physical activity (PA) (collectively known as 24-hour movement behaviours) over a 24-hour period during this school transition period. Further, the combined associations between time spent in 24-hour movement behaviours and psychosocial health are still under-researched in children. This information may inform the development of future movement behaviour intervention strategies and guidelines to assist children in making a healthy transition to secondary school. The overall aim of this doctoral thesis was to explore changes in 24-hour movement behaviours and their associations with children’s psychosocial health over the transition from primary to secondary school. Methods This thesis is comprised of four research papers, one of which is a systematic literature review and the other three are original research studies using data from two longitudinal surveys. The first and third studies analysed primary data from a longitudinal school-based survey that followed a cohort of children in New South Wales, Australia from their final year of primary school (Year-6; aged 10-12y) to their first year of secondary school (Year-7; aged 11-13y). The second study used national data from Waves 4 (2010) and 5 (2012) of the Longitudinal Study of Australia Children (Kindergarten cohort) when participants were in primary (aged 10-11y) and secondary school (aged 12-13y), respectively. Results The systematic literature review identified five articles that reported only changes in PA, while one reported changes in both PA and sedentary behaviour during the school transition period. There were no studies that examined changes in sleep duration or changes in all three movement behaviours concurrently. The first study (n=83) investigated changes in the accelerometer-measured 24-hour movement behaviour composition and adherence to the Australian 24-Hour Movement Guidelines during the school transition period. An unfavourable change was observed in the movement behaviour composition, with increased time spent sedentary and decreased time in sleep and PA. The change in the weekday movement behaviour composition was significantly more prominent compared to that of the weekend. Furthermore, there was a substantial decrease in the proportion of children meeting the integrated 24-hour movement guidelines (i.e., from 20.5% to 3.6%). The second study (n=909) investigated changes in the domain-specific movement behaviour composition as measured by a single-day time-use diary (67.4% school day; 32.6% non-school day), and explored whether these changes were associated with changes in children’s psychosocial health during this transition period. A more drastic change in movement behaviour composition was observed among the school day sample compared to the non-school day sample. Furthermore, the change in movement behaviour composition was significantly related to changes in prosocial behaviour among boys. Specifically, increased time spent in social activities and recreational screen use (relative to other activity domains) were associated with decreased prosocial behaviour. There were no significant associations between the change in movement behaviour composition and the changes in psychosocial health among girls. The third study examined the cross-sectional (n=127) and longitudinal associations (n=88) between 24-hour movement behaviour composition, recreational screen use and children’s psychosocial health. The movement behaviour composition and recreational screen use levels were independently associated with psychosocial health outcomes cross-sectionally but not longitudinally. Relative to other behaviours, more time spent in sleep and less time spent in light-intensity PA were associated with lower levels of internalising problems and total psychosocial difficulties. Conversely, higher sedentary time was associated with greater internalising problems. High levels of recreational screen use (\u3e2 h/day) were associated with greater externalising problems, total psychosocial difficulties and psychological distress. Conclusion This thesis has provided new evidence to advance the understanding of children’s 24-hour movement behaviours and their combined associations with psychosocial health during the transition from primary to secondary school. It is recommended that an integrated intervention approach addressing the full composition of 24-hour movement behaviours be adopted to effectively improve children’s movement behaviour profiles during this transition period. Future research should also continue to measure and analyse both intensity- and domain-specific movement behaviour compositions given the differing associations noted with children’s psychosocial health

Mental work stimulates cardiovascular responses through a reduction in cardiac parasympathetic modulation in men and women

Mental Work (MW) stimulates Cardiovascular (CV) functions in healthy adults and a reduction in cardiac parasympathetic modulation could be one mechanism involved in such a response. The influence of sex on these CV responses remains ambiguous. The aim of the study was to evaluate CV impacts of MW in healthy individuals and whether sex influences CV responses induced by MW. The impact of a 45-min reading and writing session vs. a control condition, on Blood Pressure (BP), Heart Rate (HR), and Heart Rate Variability (HRV), was evaluated in 44 healthy adults with the use of a randomized crossover design. The influence of sex on those variables was then evaluated. Diastolic BP (74 ± 1 vs. 69 ± 1 mmHg; p < 0.05) and mean arterial pressure (MAP; 87 ± 7 vs. 83 ± 8 mmHg; p < 0.005), HR (68 ± 1 vs. 62 ± 1 bpm; p < 0.0001) and low frequency/high frequency ratio (2.8 ± 0.1 vs. 2.0 ± 0.1; p < 0.0001) were higher, while global HRV (SDNN: 84 ± 3 vs.104 ± 3 ms; p < 0.0001) and cardiac parasympathetic activity were lower during MW (p < 0.0001) vs. the control condition in the whole sample. During both experimental conditions, HR was higher (p < 0.0001), while BP, rMSSD, pNN50 and low frequency component of HRV were lower in women compared to men (all p < 0.05). The intensity of the cognitive demand and its influence on CV variables were comparable between men and women. These results support that MW increases BP and HR through decrement in cardiac parasympathetic modulation in healthy subjects and suggest that sex does not influence CV responses induced by cognitive demand of similar intensity

Are Children Like Werewolves? : Full Moon and Its Association with Sleep and Activity Behaviors in an International Sample of Children

In order to verify if the full moon is associated with sleep and activity behaviors, we used a 12-country study providing 33,710 24-h accelerometer recordings of sleep and activity. The present observational, cross-sectional study included 5812 children ages 9-11 years from study sites that represented all inhabited continents and wide ranges of human development (Australia, Brazil, Canada, China, Colombia, Finland, India, Kenya, Portugal, South Africa, United Kingdom, and United States). Three moon phases were used in this analysis: full moon (4 days; reference), half moon (5-9 days), and new moon (+10-14 days) from nearest full moon. Nocturnal sleep duration, moderate -to vigorous physical activity (MVPA), light-intensity physical activity (LPA), and total sedentary time (SED) were monitored over seven consecutive days using a waist -worn accelerometer worn 24 h a day. Only sleep duration was found to significantly differ between moon phases (-5 min/night shorter during full moon compared to new moon). Differences in MVPA, LPA, and SED between moon phases were negligible and non-significant (Peer reviewe