Physical environment features that predict outdoor active play can be measured using Google Street View images.

BACKGROUND: Childrens' outdoor active play is an important part of their development. Play behaviour can be predicted by a variety of physical and social environmental features. Some of these features are difficult to measure with traditional data sources. METHODS: This study investigated the viability of a machine learning method using Google Street View images for measurement of these environmental features. Models to measure natural features, pedestrian traffic, vehicle traffic, bicycle traffic, traffic signals, and sidewalks were developed in one city and tested in another. RESULTS: The models performed well for features that are time invariant, but poorly for features that change over time, especially when tested outside of the context where they were initially trained. CONCLUSION: This method provides a potential automated data source for the development of prediction models for a variety of physical and social environment features using publicly accessible street view images.

The 2022 ParticipACTION Report Card on Physical Activity for Children and Youth: Focus on the COVID-19 pandemic impact and equity-deserving groups.

Introduction: The ParticipACTION Report Card on Physical Activity for Children and Youth is the most comprehensive national assessment of physical activity and related behaviors, characteristics, and opportunities for children and youth. The 2022 Report Card assigned grades based on data gathered during the COVID-19 pandemic to reflect this extraordinary time-period in Canada. Further, while not graded, efforts were made to summarize key findings for early years children and those identifying as: having a disability, Indigenous, 2SLGBTQ+, newcomers to Canada, racialized, or girls. The purpose of this paper is to summarize the 2022 ParticipACTION Report Card on Physical Activity for Children and Youth. Methods: The best available physical activity data captured during the whole COVID-19 pandemic was synthesized across 14 different indicators in four categories. The 2022 Report Card Research Committee assigned letter grades (i.e., A-F) based on expert consensus of the evidence. Synthesis: Grades were assigned for: Daily Behaviors (Overall Physical Activity: D; Active Play: D-; Active Transportation: C-; Organized Sport: C+; Physical Education: Incomplete [INC]; Sedentary Behaviors: F; Sleep: B; 24-Hour Movement Behaviors: F), Individual Characteristics (Physical Literacy: INC; Physical Fitness: INC), Spaces and Places (Household: C, School: B-, Community and Environment: B), and Strategies and Investments (Government: B-). Compared to the 2020 Report Card, the COVID-19 specific grades increased for Active Play and Active Transportation; and decreased for Overall Physical Activity, Sedentary Behaviors, Organized Sport, and Community and Environment. There were many data gaps for equity-deserving groups. Conclusion: During the COVID-19 pandemic, the grade for Overall Physical Activity decreased from a D+ (2020) to a D, coinciding with decreases in grades reflecting fewer opportunities for sport and community/facility-based activities as well as higher levels of sedentary behaviors. Fortunately, improvements in Active Transportation and Active Play during COVID-19 prevented a worse shift in children's health behaviors. Efforts are needed to improve physical activity for children and youth during and post-pandemic, with a greater emphasis on equity-deserving groups.

Economic burden of low muscle strength in Canadian adults.

The economic cost associated with low muscle strength in Canadian adults is unknown. The total annual economic burden of low muscle strength in Canadian adults represents 2.2% of the overall burden of illness costs in 2021. We estimated that $546 million per year would be saved if the prevalence of low handgrip strength was reduced by 10%.

Compositional associations of time spent in sleep, screen time, and physical activity with polysubstance use in adolescents.

This study of grade 6-10 students used compositional analysis to examine the relationship between the movement behavior composition (time in sleep, screen time, and physical activity) and polysubstance use (frequency of using cigarettes, alternative tobacco products, alcohol, cannabis, and illicit drugs). In grades 6-8 students and grades 9-10 girls: 1) sleep was negatively associated with polysubstance use, 2) screen time was positively associated with polysubstance use, and 3) reallocating physical activity or screen time into sleep was associated with lower polysubstance use. In grades 9-10 boys, reallocating 60 min/day from physical activity into screen time or sleep was associated with greater polysubstance use.

The effects of single-leg disuse on skeletal muscle strength and size in the nonimmobilized leg of uninjured adults: a meta-analysis.

The effects of single-leg immobilization on changes in skeletal muscle strength and size in the nonimmobilized leg remain controversial. Some studies have shown decreases, or even increases, in skeletal muscle strength and size of the nonimmobilized leg, thus challenging its role as an internal control. Here, we meta-analyze changes in knee extensor strength and size in the nonimmobilized leg of noninjured adults who participated in single-leg disuse studies. We extracted data from the nonimmobilized leg of participants from 15 of 40 studies included in our previous meta-analysis on single-leg disuse. Single-leg disuse had a trivial effect on knee extensor strength (Hedges' gav = -0.13 [-0.23, -0.03], P < 0.01, -3.6 ± 5.6%, N = 13 studies, n = 194 participants) and no impact on knee extensor size (0.06 [-0.06, 0.19], P = 0.21, 0.8 ± 2.9%, N = 9, n = 107) in the nonimmobilized leg. By comparison, single-leg disuse had a large effect on knee extensor strength (-0.85 [-1.01, -0.69], P < 0.01, -20.4 ± 6.4%; mean difference between legs = 16.8 ± 7.8% [12.8, 20.8], P < 0.001) and a medium effect on knee extensor size (-0.40 [-0.55, -0.25], P < 0.01, -7.0 ± 4%; mean difference = 7.8 ± 5.6% [11.6, 4.0], P < 0.002) in the immobilized leg. These results highlight the utility of the nonimmobilized leg to act as an internal control in single-leg immobilization studies.NEW & NOTEWORTHY Our meta-analyses show a trivial effect of single-leg immobilization on leg extensor strength and no effect on leg extensor size in the nonimmobilized leg in uninjured adults. Thus, the nonimmobilized leg in single-leg immobilization studies can serve as useful internal control when examining changes in knee extensor strength and size.

The association between social media use and physical activity among Canadian adolescents: a Health Behaviour in School-aged Children (HBSC) study.

OBJECTIVE: To determine the association between social media use (SMU) and physical activity (PA) among Canadian adolescents. METHODS: We used data from 12,358 participants in grades 6 to 10 who responded to the Canadian component of the 2017/2018 Health Behaviour in School-aged Children (HBSC) survey. Social media intensity and problematic SMU were assessed using a 4-point mutually exclusive scale that contained three categories based on intensity (non-active, active, and intense SMU) and one category based on the presence of addiction-like symptoms irrespective of intensity (problematic SMU). PA was assessed for five domains (i.e., school curriculum, organized sport, exercise, outdoor play, and active transport) and dichotomized using the first quartile to represent high PA engagement in each domain. Meeting PA recommendation of 60 min per day of moderate-to-vigorous PA was calculated using the sum of the five domains. Logistic regression models were used to assess the association between SMU and PA, with active SMU used as the reference group for all models. RESULTS: Non-active SMU was associated with lower odds of meeting the daily PA recommendations and of high engagement in all five domains of PA when compared to active SMU. Intense SMU was associated with higher odds of meeting the daily PA recommendations. Problematic SMU was not associated with meeting daily PA recommendations, but it was significantly associated with lower odds of high PA engagement in the exercise domain. CONCLUSION: The findings of this study suggest that non-active SMU was significantly associated with lower PA levels. Problematic SMU was only significantly associated with lower PA levels in the exercise domain. Intense SMU was associated with higher odds of meeting the PA recommendation.

RéSUMé: OBJECTIF: Établir la relation entre l'utilisation des médias sociaux et l'activité physique chez les adolescents canadiens. MéTHODES: Nous avons utilisé les données de 12 358 participants de la 6e à la 10e année qui ont répondu au volet canadien de l'Enquête sur les comportements de santé des jeunes d'âge scolaire de 2017­2018 (HBSC). L'intensité des médias sociaux et leur utilisation problématique ont été évaluées à l'aide d'une échelle à quatre points mutuellement exclusifs contenant trois catégories basées sur l'intensité (utilisation non active, active et intense des médias sociaux) et une catégorie basée sur la présence de symptômes de dépendance indépendamment de l'intensité (utilisation problématique des médias sociaux). L'activité physique a été évaluée pour cinq domaines (c'est-à-dire le programme scolaire, le sport organisé, l'exercice, le jeu en plein air et le transport actif) et dichotomisée en utilisant le premier quartile pour représenter la participation à une activité physique élevée dans chaque domaine. Le respect de la recommandation de 60 min par jour d'activité physique modérée à vigoureuse a été calculé en utilisant la somme des cinq domaines. Des modèles de régression logistique ont été utilisés pour évaluer la relation entre l'utilisation des médias sociaux et l'activité physique, l'utilisation active des médias sociaux étant utilisée comme groupe de référence pour tous les modèles. RéSULTATS: L'utilisation non active des médias sociaux était associée à une probabilité plus faible de respecter les recommandations en matière d'activité physique quotidienne et à une participation élevée dans les cinq domaines de l'activité physique, par rapport à l'utilisation active des médias sociaux. Une utilisation intense des médias sociaux était associée à une probabilité plus élevée de respecter les recommandations en matière d'activité physique quotidienne. Une utilisation problématique des médias sociaux n'était pas associée au respect des recommandations en matière d'activité physique quotidienne, mais elle était fortement associée à une probabilité moindre de participation élevée à une activité physique dans le domaine de l'exercice. CONCLUSION: Les résultats de cette étude suggèrent que l'utilisation non active des médias sociaux est fortement associée à des niveaux d'activité physique plus faibles. Une utilisation problématique des médias sociaux n'était fortement associée à des niveaux d'activité physique plus faibles que dans le domaine de l'exercice. Une utilisation intense des médias sociaux était associée à une probabilité plus élevée de respecter la recommandation en matière d'activité physique.

Single-leg disuse decreases skeletal muscle strength, size, and power in uninjured adults: A systematic review and meta-analysis.

We aimed to quantify declines from baseline in lower limb skeletal muscle size and strength of uninjured adults following single-leg disuse. We searched EMBASE, Medline, CINAHL, and CCRCT up to 30 January 2022. Studies were included in the systematic review if they (1) recruited uninjured participants; (2) were an original experimental study; (3) employed a single-leg disuse model; and (4) reported muscle strength, size, or power data following a period of single-leg disuse for at least one group without a countermeasure. Studies were excluded if they (1) did not meet all inclusion criteria; (2) were not in English; (3) reported previously published muscle strength, size, or power data; or (4) could not be sourced from two different libraries, repeated online searches, and the authors. We used the Cochrane Risk of Bias Assessment Tool to assess risk of bias. We then performed random-effects meta-analyses on studies reporting measures of leg extension strength and extensor size. Our search revealed 6548 studies, and 86 were included in our systematic review. Data from 35 and 20 studies were then included in the meta-analyses for measures of leg extensor strength and size, respectively (40 different studies). No meta-analysis for muscle power was performed due to insufficient homogenous data. Effect sizes (Hedges' gav ) with 95% confidence intervals for leg extensor strength were all durations = -0.80 [-0.92, -0.68] (n = 429 participants; n = 68 aged 40 years or older; n ≥ 78 females); ≤7 days of disuse = -0.57 [-0.75, -0.40] (n = 151); >7 days and ≤14 days = -0.93 [-1.12, -0.74] (n = 206); and >14 days = -0.95 [-1.20, -0.70] (n = 72). Effect sizes for measures of leg extensor size were all durations = -0.41 [-0.51, -0.31] (n = 233; n = 32 aged 40 years or older; n ≥ 42 females); ≤7 days = -0.26 [-0.36, -0.16] (n = 84); >7 days and ≤14 days = -0.49 [-0.67, -0.30] (n = 102); and >14 days = -0.52 [-0.74, -0.30] (n = 47). Decreases in leg extensor strength (cast: -0.94 [-1.30, -0.59] (n = 73); brace: -0.90 [-1.18, -0.63] (n = 106)) and size (cast: -0.61[-0.87, -0.35] (n = 41); brace: (-0.48 [-1.04, 0.07] (n = 41)) following 14 days of disuse did not differ for cast and brace disuse models. Single-leg disuse in adults resulted in a decline in leg extensor strength and size that reached a nadir beyond 14 days. Bracing and casting led to similar declines in leg extensor strength and size following 14 days of disuse. Studies including females and males and adults over 40 years of age are lacking.

Economic burden of low cardiorespiratory fitness in Canada.

The objective of this study was to estimate health care and health-related productivity costs associated with low cardiorespiratory fitness (CRF) in Canadian adults. We also estimated costs that would be avoided by a 10 percentage point prevalence reduction in low CRF. A prevalence-based approach was used to estimate the economic costs associated with low CRF. Three pieces of information were used: (1) the pooled relative risk estimates of adverse health outcomes consistently associated with low CRF obtained from meta-analyses of prospective cohort studies; (2) the prevalence of low CRF in Canadian men and women obtained from a nationally representative sample; and (3) the direct (health care) and indirect (lost productivity due to premature mortality) costs of the adverse health outcomes based on the Economic Burden of Illness in Canada data. We estimated the total annual economic burden of low CRF in Canadian adults at CAD$3.6 billion, representing 2.7% of the overall Canadian burden of illness costs in 2021. The three most expensive chronic diseases attributable to low CRF were type 2 diabetes (CAD$1.3 billion), heart disease (CAD$701 million), and depression/anxiety (CAD$565 million). Prescription drug expenditures and hospital care expenditures were the main contributors to the total economic burden. An absolute 10% reduction in the prevalence of low CRF (from 45.5% to 35.5%) would save an estimated CAD$644 million per year in costs. In conclusion, low CRF is an important contributor to the economic burden of illness in Canada. Evidence-based and cost-effective strategies that aim to increase CRF at the population level may help alleviate health care costs and improve health.

Economic burden of excessive sedentary behaviour in Canada.

OBJECTIVE: To estimate health care and health-related productivity costs associated with excessive sedentary behaviour (> 8 h/day and > 9 h/day) in Canadian adults. METHODS: Three pieces of information were used to estimate costs: (1) the pooled relative risk estimates of adverse health outcomes consistently shown to be associated with excessive sedentary behaviour, gathered from meta-analyses of prospective cohort studies; (2) the prevalence of excessive sedentary behaviour in Canadian men and women, obtained using waist-worn accelerometry in a nationally representative sample of adults (Canadian Health Measures Survey 2018-2019); and (3) the direct (health care) and indirect (lost productivity due to premature mortality) costs of the adverse health outcomes, selected using the Economic Burden of Illness in Canada 2010 data. The 2010 costs were then adjusted to 2021 costs to account for inflation, population growth, and higher average earnings. A Monte Carlo simulation was conducted to account for uncertainty in the model. RESULTS: The total costs of excessive sedentary behaviour in Canada were $2.2 billion (8 h/day cut-point) and $1.8 billion (9 h/day cut-point) in 2021, representing 1.6% and 1.3% of the overall burden of illness costs, respectively. The two most expensive chronic diseases attributable to excessive sedentary behaviour were cardiovascular disease and type 2 diabetes. A 10% decrease in excessive sedentary behaviour (from 87.7% to 77.7%) would save an estimated $219 million per year in costs. CONCLUSION: Excessive sedentary behaviour significantly contributes to the economic burden of illness in Canada. There is a need for evidence-based and cost-effective strategies that reduce excessive sedentary behaviour in the population.

RéSUMé: OBJECTIF: Estimer le coût des soins de santé et le coût de productivité lié à la santé associés au comportement sédentaire excessif (> 8 heures/jour et > 9 heures/jour) chez les Canadiennes et les Canadiens adultes. MéTHODE: Trois informations ont servi à estimer ces coûts : 1) les estimations combinées du risque relatif des résultats sanitaires indésirables uniformément associés au comportement sédentaire excessif, collectées à partir de méta-analyses d'études prospectives de cohortes; 2) la prévalence du comportement sédentaire excessif chez les Canadiennes et les Canadiens, obtenue à l'aide d'un accéléromètre porté à la taille par un échantillon représentatif national d'adultes (Enquête canadienne sur les mesures de la santé 2018-2019); et 3) les coûts directs (soins de santé) et indirects (perte de productivité due à la mortalité prématurée) des résultats sanitaires indésirables sélectionnés, d'après les données du Fardeau économique de la maladie au Canada de 2010. Les coûts de 2010 ont ensuite été ajustés aux coûts de 2021 pour tenir compte de l'inflation, de la croissance démographique et de la hausse moyenne des revenus. Nous avons effectué une simulation de Monte-Carlo pour tenir compte de l'incertitude du modèle. RéSULTATS: Les coûts totaux du comportement sédentaire excessif au Canada étaient de 2,2 milliards de dollars (point de coupure de 8 heures/jour) et de 1,8 milliard de dollars (point de coupure de 9 heures/jour) en 2021, ce qui représente 1,6 % et 1,3 % du fardeau global des coûts des maladies, respectivement. Les deux maladies chroniques les plus chères imputables au comportement sédentaire excessif étaient les maladies cardiovasculaires et le diabète de type 2. Une baisse de 10 % du comportement sédentaire excessif (de 87,7 % à 77,7 %) économiserait environ 219 millions de dollars de coûts par année. CONCLUSION: Le comportement sédentaire excessif contribue de façon significative au fardeau économique de la maladie au Canada. Il nous faut des stratégies fondées sur les preuves et efficaces par rapport au coût pour réduire le comportement sédentaire excessif dans la population.

Economic burden of insomnia symptoms in Canada.

OBJECTIVE: To estimate health care and productivity costs associated with insomnia symptoms in Canadian adults. METHODS: Three pieces of information were needed to calculate estimates based on a prevalence-based approach: (1) the pooled relative risk estimates of health outcomes consistently associated with insomnia symptoms obtained from recent meta-analyses of prospective cohort studies; (2) the direct (health care) and indirect (lost productivity due to premature mortality) costs of these health outcomes using the Economic Burden of Illness in Canada information; and (3) the prevalence of insomnia symptoms in Canadian men (18.1%) and women (29.5%) obtained from a nationally-representative survey. RESULTS: The direct, indirect, and total costs of insomnia symptoms in Canada in 2021 were $1.9 billion, $12.6 million, and $1.9 billion, respectively. This value represents 1.9% of the overall burden of illness costs for 2021 in Canada. The 2 most expensive chronic diseases attributable to insomnia symptoms were type 2 diabetes ($754 million) and depression ($706 million). The main contributor to the costs for type 2 diabetes and depression was prescription drugs. A 5% decrease in insomnia symptoms (from 23.8% to 18.8%) would result in an estimated $353 million in avoided costs while a 5% increase in insomnia symptoms (from 23.8% to 28.8%) would result in an estimated $333 million in additional expenditures yearly. CONCLUSIONS: Insomnia symptoms greatly contribute to the economic burden of illness in Canada. Reducing the prevalence of insomnia symptoms would reduce its societal burden.

The neighborhood physical environment and the 24-hour movement behavior composition among children.

The time spent in sleep, sedentary behavior, and physical activity form a 24-hour movement behavior composition. The objective was to identify neighborhood physical environment features associated with multiple components of the movement behavior composition among 10 to 13-year-olds. Twenty-three neighborhood physical environment features were measured in 1 km buffers from the participants' homes and from these walkability, traffic safety, dedicated play spaces, non-dedicated play spaces, noise, and artificial light indices were created. Moderate-to-vigorous physical activity, light physical activity, sedentary time, and sleep duration were measured. Compositional data analysis was used to establish differences in movement behaviors according to neighborhood physical environment features. One hundred and sixteen associations, reflecting four movement behaviors X 29 environment variables and indices, were examined. Only three of these were statistically significant. Therefore, neighborhood physical environment features were not meaningful correlates of 24-hour movement behaviors.

Top 10 International Priorities for Physical Fitness Research and Surveillance Among Children and Adolescents: A Twin-Panel Delphi Study.

BACKGROUND: The measurement of physical fitness has a history that dates back nearly 200 years. Recently, there has been an increase in international research and surveillance on physical fitness creating a need for setting international priorities that could help guide future efforts. OBJECTIVE: This study aimed to produce a list of the top 10 international priorities for research and surveillance on physical fitness among children and adolescents. METHODS: Using a twin-panel Delphi method, two independent panels consisting of 46 international experts were identified (panel 1 = 28, panel 2 = 18). The panel participants were asked to list up to five priorities for research or surveillance (round 1), and then rated the items from their own panel on a 5-point Likert scale of importance (round 2). In round 3, experts were asked to rate the priorities identified by the other panel. RESULTS: There was strong between-panel agreement (panel 1: rs = 0.76, p < 0.01; panel 2: rs = 0.77, p < 0.01) in the priorities identified. The list of the final top 10 priorities included (i) "conduct longitudinal studies to assess changes in fitness and associations with health". This was followed by (ii) "use fitness surveillance to inform decision making", and (iii) "implement regular and consistent international/national fitness surveys using common measures". CONCLUSIONS: The priorities identified in this study provide guidance for future international collaborations and research efforts on the physical fitness of children and adolescents over the next decade and beyond.

Years of life gained when meeting sleep duration recommendations in Canada.

OBJECTIVE: To estimate the years of life gained when meeting the sleep duration recommendations across the adult lifespan. METHODS: Three pieces of information were used to estimate and compare life expectancy at each age of adult life among Canadian adults who did and did not meet sleep duration recommendations: (i) the prevalence of self-reported short sleep duration, recommended sleep duration, and long sleep duration; (ii) the relative risks of all-cause mortality associated with sleep duration obtained from recent meta-analyses; and (iii) the probability of death during each year of life obtained from life tables. RESULTS: Adults who meet the sleep duration recommendations have an estimated life expectancy at age 20 years that is 1.2 years longer than short sleepers and 2.6 years longer than long sleepers. Differences between men and women were minimal. CONCLUSION: Meeting sleep duration recommendations is associated with increases in longevity in Canada.

A compositional analysis study of body composition and cardiometabolic risk factors.

OBJECTIVE: This cross-sectional study used compositional data analysis (CoDA) to do the following: 1) analyze the relative associations between fat and lean tissues with cardiometabolic risk factors; and 2) estimate how these risk factors would change if equivalent mass was displaced from one tissue to another. Differences between CoDA and traditional regression were explored. METHODS: A total of 397 adults with overweight or obesity were studied. Body composition consisted of visceral fat, abdominal subcutaneous fat, peripheral subcutaneous fat, other fat depots, skeletal muscle, and other lean tissues. The outcomes were a continuous metabolic syndrome score (primary outcome) and eight other cardiometabolic risk factors (secondary outcomes). Associations were examined using CoDA and traditional linear regression. RESULTS: Visceral fat mass, relative to the mass of the remaining tissues, was significantly associated with the metabolic syndrome score and five of eight remaining risk factors (p < 0.05). The relative contribution of the remaining tissues was not consistently associated with the study outcomes. Displacing equivalent mass from visceral fat into the remaining tissues was associated with meaningful decreases in the metabolic syndrome score. Regression estimates for CoDA and traditional regression differed in size and statistical significance. CONCLUSIONS: These CoDA findings reinforce that excess visceral fat contributes to less-favorable cardiometabolic risk factors.

Associations of Passive and Active Screen Time With Psychosomatic Complaints of Adolescents.

INTRODUCTION: Increased screen time is a ubiquitous part of adolescent life and is adversely associated with their well-being. However, it remains unclear whether different types of screen time have equivalent associations, or if relationships are dose-dependent. METHODS: The data were from 2 nationally representative Health Behaviour in School-aged Children (2010, 2014) surveys across 44 European and North American countries. Psychosomatic health was assessed using 8 complaints and dichotomized as high or low. Discretionary time spent on passive (e.g., TV) and mentally active (e.g., electronic games, computer use) screen-based activities was categorized into 3 groups. Data were analyzed in 2021. RESULTS: The study included 414,489 adolescents (average age, 13.6 [SD=1.63] years; 51.1% girls). Multilevel modeling showed that psychosomatic complaints increased monotonically once all forms of screen time exceeded 2 hours/day. Adolescents reporting high (>4 hours/day) TV time, compared with those reporting low (≤2 hours/day), had higher odds of reporting psychosomatic complaints with 67% higher odds (OR=1.67, 95% CI=1.62, 1.72) in boys and 71% (OR=1.71, 95% CI=1.66, 1.75) in girls. High electronic game use was associated with psychosomatic complaints, with odds being 78% higher in boys (OR=1.78, 95% CI=1.73, 1.84) and 88% higher in girls (OR=1.88, 95% CI=1.82, 1.94). Similar associations were found between computer use and psychosomatic complaints. CONCLUSIONS: Passive and mentally active screen time are adversely associated with psychosomatic complaints in a dose-dependent manner, with associations slightly stronger for active than passive screen time. This study supports limiting any type of screen time, either passive or active, to 2 hours/day to foster well-being.

Economic burden of insufficient sleep duration in Canadian adults.

OBJECTIVE: To provide estimates of the health care and productivity costs associated with insufficient sleep duration (<7 hours per night) in Canadian adults. METHODS: A prevalence-based approach was used to estimate the economic costs associated with insufficient sleep duration. Estimates relied on 3 pieces of information: (1) the relative risks of health outcomes consistently associated with insufficient sleep duration obtained from recent meta-analyses; (2) the direct (health care) and indirect (health-related losses of productivity) costs of these health outcomes obtained from the Economic Burden of Illness in Canada data; and (3) the prevalence of insufficient sleep duration in Canadian adults obtained from a representative national survey (17.2%). RESULTS: The estimated direct, indirect, and total costs of insufficient sleep duration in Canada in 2020 were $484 million, $18 million, and $502 million, respectively. These values represent 0.5% (direct), 2.7% (indirect), and 0.5% (total) of the overall burden of illness costs for Canada (estimated at $102 billion). The 2 most expensive chronic diseases attributable to insufficient sleep duration were depression ($219 million) and type 2 diabetes ($92 million). The main contributors of these health care costs were related to hospital care (for coronary heart disease and obesity), prescription drugs (for type 2 diabetes and depression), physician care (for hypertension and cognitive disorders), and mortality (for accidents/injuries). A 5% decrease in the prevalence of insufficient sleep duration (from 17.2% to 12.2%) in Canadian adults would lead to a yearly savings of $148 million. CONCLUSIONS: Insufficient sleep duration is an important contributor to health care spending and health-related losses of productivity in Canada. Studies are needed to test cost-effective sleep health interventions at the population level.

Timing of physical activity within the 24-hour day and its influence on health: a systematic review. / Moment choisi pour faire de l'activité physique sur 24 heures et son influence sur la santé : revue systématique.

BACKGROUND: Recent studies report that the health benefits of physical activity differ depending on whether the activity is performed in the morning, afternoon or evening. The purpose of this systematic review was to examine whether the timing of physical activity within the 24-hour day is associated with health. METHODS: Five databases were searched for English or French language peer-reviewed studies that examined whether the timing of physical activity within the day is associated with health. No limits were placed on publication year, study population, study design or health outcomes. Studies that examined acute effects of physical activity or timing of physical activity around food intake were excluded. RESULTS: This systematic review examined 35 studies, with 17 259 participants, and the following health outcomes: measures of sleep health, adiposity, fat-free mass and muscle size, cardiometabolic biomarkers, physical function and mobility, mental health, and risk of cardiovascular disease, cancer, and mortality. Heterogeneity across studies precluded meta-analyses, and we present our findings using narrative syntheses. Of the 35 studies, 11 reported that morning physical activity provides greater health benefits than afternoon/ evening physical activity, while 12 found that morning physical activity provides fewer health benefits than afternoon/evening physical. In the remaining 12 studies, there was no clear difference in health benefits based on the timing of physical activity. The quality of evidence for the different health outcomes across study designs was very low. CONCLUSION: There is no consistent evidence that physical activity at one time of day provides more favourable health benefits than physical activity at a different time of day. (PROSPERO registration no.: CRD42021231088).

Timing of sedentary behaviour and access to sedentary activities in the bedroom and their association with sleep quality and duration in children and youth: a systematic review. / Revue systématique des liens entre, d'une part, l'horaire des comportements sédentaires et l'accès à des activités sédentaires dans la chambre et, d'autre part, la qualité et la durée du sommeil chez les enfants et les adolescents.

BACKGROUND: The purpose of this study was to systematically review the relationship between the timing of sedentary behaviours and access to sedentary activities in the bedroom with sleep duration and quality in children and youth. A secondary purpose was to examine whether these relationships differ when comparing screen-based and non-screen-based sedentary activities. METHODS: We searched four databases for peer-reviewed studies published between 1 January 2010 and 19 January 2021. Risk of bias assessment for each study and certainty of evidence were assessed using the GRADE framework. RESULTS: We identified 44 eligible papers reporting data from 42 separate datasets and including 239 267 participants. Evening participation in screen-based sedentary behaviours and access to screen-based devices in the bedroom were associated with reduced sleep duration and quality. Daytime screen use was also associated with reduced sleep duration, although this was examined in relatively few studies. Whether performed during the day or night, non-screen-based sedentary behaviours were not consistently associated with sleep duration or quality. The quality of evidence was rated as low to very low for all outcomes. CONCLUSION: In order to maximize sleep duration and quality, children and youth should be encouraged to minimize screen time in the evening and remove screens from bedrooms. (PROSPERO registration no.: CRD42020189082).

Sleep timing and health indicators in children and adolescents: a systematic review. / Horaire de sommeil et indicateurs de santé chez les enfants et les adolescents : revue systématique.

INTRODUCTION: To continue to inform sleep health guidelines and the development of evidence-based healthy sleep interventions for children and adolescents, it is important to better understand the associations between sleep timing (bedtime, wake-up time, midpoint of sleep) and various health indicators. The objective of this systematic review was to examine the associations between sleep timing and 9 health indicators in apparently healthy children and adolescents 5 to 18 years old. METHODS: Studies published in the 10 years preceding January 2021 were identified from searches in four electronic databases. This systematic review followed the guidelines prescribed in PRISMA 2020, the methodological quality and risk of bias were scored, and the summary of results used a best-evidence approach for accurate and reliable reporting. RESULTS: Forty-six observational studies from 21 countries with 208 992 unique participants were included. Sleep timing was assessed objectively using actigraphy in 24 studies and subjectively in 22 studies. The lack of studies in some of the health outcomes and heterogeneity in others necessitated using a narrative synthesis rather than a metaanalysis. Findings suggest that later sleep timing is associated with poorer emotional regulation, lower cognitive function/academic achievement, shorter sleep duration/ poorer sleep quality, poorer eating behaviours, lower physical activity levels and more sedentary behaviours, but few studies demonstrated associations between sleep timing and adiposity, quality of life/well-being, accidents/injuries, and biomarkers of cardiometabolic risk. The quality of evidence was rated as "very low" across health outcomes using GRADE. CONCLUSION: The available evidence, which relies on cross-sectional findings, suggests that earlier sleep timing is beneficial for the health of school-aged children and adolescents. Longitudinal studies and randomized controlled trials are needed to better advance this field of research. (PROSPERO registration no.: CRD42020173585).