Mark S. Tremblay

Systematic review of sedentary behaviour and health indicators in school-aged children and youth

Accumulating evidence suggests that, independent of physical activity levels, sedentary behaviours are associated with increased risk of cardio-metabolic disease, all-cause mortality, and a variety of physiological and psychological problems. Therefore, the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5-17 years. Online databases (MEDLINE, EMBASE and PsycINFO), personal libraries and government documents were searched for relevant studies examining time spent engaging in sedentary behaviours and six specific health indicators (body composition, fitness, metabolic syndrome and cardiovascular disease, self-esteem, pro-social behaviour and academic achievement). 232 studies including 983,840 participants met inclusion criteria and were included in the review. Television (TV) watching was the most common measure of sedentary behaviour and body composition was the most common outcome measure. Qualitative analysis of all studies revealed a dose-response relation between increased sedentary behaviour and unfavourable health outcomes. Watching TV for more than 2 hours per day was associated with unfavourable body composition, decreased fitness, lowered scores for self-esteem and pro-social behaviour and decreased academic achievement. Meta-analysis was completed for randomized controlled studies that aimed to reduce sedentary time and reported change in body mass index (BMI) as their primary outcome. In this regard, a meta-analysis revealed an overall significant effect of -0.81 (95% CI of -1.44 to -0.17, p = 0.01) indicating an overall decrease in mean BMI associated with the interventions. There is a large body of evidence from all study designs which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5-17 years. In particular, the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health, and that lowering sedentary time leads to reductions in BMI.

The accuracy of self-reported smoking: A systematic review of the relationship between self-reported and cotinine-assessed smoking status

INTRODUCTION Smoking is a leading cause of premature mortality and preventable morbidity. Surveillance is most often based on self-reported data, but studies have shown that self-reports tend to underestimate smoking status. METHODS This study systematically reviewed the literature to measure the concordance between self-reported smoking status and smoking status determined through measures of cotinine in biological fluids. Four electronic databases were searched to identify observational and experimental studies on adult populations over the age of 18 years. RESULTS Searching identified 67 studies that met the eligibility criteria and examined the relationship between self-reported smoking and smoking confirmed by cotinine measurement. Overall, the data show trends of underestimation when smoking prevalence is based on self-report and varying sensitivity levels for self-reported estimates depending on the population studied and the medium in which the biological sample is measured. Sensitivity values were consistently higher when cotinine was measured in saliva instead of urine or blood. Meta-analysis was not appropriate because of the substantial heterogeneity among the cutpoints used to define smokers and the poor reporting on outcomes of interest. DISCUSSION Further research in this field would benefit from the standardization of cutpoints to define current smokers and the implementation of standard reporting guidelines to enhance comparability across studies. Accurate estimation of smoking status is important as data from population studies such as those included in this review are used to generate regional and national estimates of smoking status and in turn are used to allocate resources and set health priorities.

Changes in the rates of awareness, treatment and control of hypertension in Canada over the past two decades.

Background Analyses of medication databases indicate marked increases in prescribing of antihypertensive drugs in Canada over the past decade. This study was done to examine the trends in the prevalence of hypertension and in control rates in Canada between 1992 and 2009. Methods Three population-based surveys, the 1986–1992 Canadian Heart Health Surveys, the 2006 Ontario Survey on the Prevalence and Control of Hypertension and the 2007–2009 Canadian Health Measures Survey, collected self-reported health information from, and measured blood pressure among, community-dwelling adults. Results The population prevalence of hypertension was stable between 1992 and 2009 at 19.7%–21.6%. Hypertension control improved from 13.2% (95% confidence interval [CI] 10.7%–15.7%) in 1992 to 64.6% (95% CI 60.0%–69.2%) in 2009, reflecting improvements in awareness (from 56.9% [95% CI 53.1%–60.5%] in 1992 to 82.5% [95% CI 78.5%–86.0%] in 2009) and treatment (from 34.6% [95% CI 29.2%–40.0%] in 1992 to 79.0% [95% CI 71.3%–86.7%] in 2009) among people with hypertension. The size of improvements in awareness, treatment and control were similar among people who had or did not have cardiovascular comorbidities Although systolic blood pressures among patients with untreated hypertension were similar between 1992 and 2009 (ranging from 146 [95% CI 145–147] mm Hg to 148 [95% CI 144–151] mm Hg), people who did not have hypertension and patients with hypertension that was being treated showed substantially lower systolic pressures in 2009 than in 1992 (113 [95% CI 112–114] v. 117 [95% CI 117–117] mm Hg and 128 [95% CI 126–130] v. 145 [95% CI 143–147] mm Hg). Interpretation The prevalence of hypertension has remained stable among community-dwelling adults in Canada over the past two decades, but the rates for treatment and control of hypertension have improved markedly during this time.

Sedentary Behavior Research Network (SBRN) : Terminology Consensus Project process and outcome

BackgroundThe prominence of sedentary behavior research in health science has grown rapidly. With this growth there is increasing urgency for clear, common and accepted terminology and definitions. Such standardization is difficult to achieve, especially across multi-disciplinary researchers, practitioners, and industries. The Sedentary Behavior Research Network (SBRN) undertook a Terminology Consensus Project to address this need.MethodFirst, a literature review was completed to identify key terms in sedentary behavior research. These key terms were then reviewed and modified by a Steering Committee formed by SBRN. Next, SBRN members were invited to contribute to this project and interested participants reviewed and provided feedback on the proposed list of terms and draft definitions through an online survey. Finally, a conceptual model and consensus definitions (including caveats and examples for all age groups and functional abilities) were finalized based on the feedback received from the 87 SBRN member participants who responded to the original invitation and survey.ResultsConsensus definitions for the terms physical inactivity, stationary behavior, sedentary behavior, standing, screen time, non-screen-based sedentary time, sitting, reclining, lying, sedentary behavior pattern, as well as how the terms bouts, breaks, and interruptions should be used in this context are provided.ConclusionIt is hoped that the definitions resulting from this comprehensive, transparent, and broad-based participatory process will result in standardized terminology that is widely supported and adopted, thereby advancing future research, interventions, policies, and practices related to sedentary behaviors.

The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE): design and methods

BackgroundThe primary aim of the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) was to determine the relationships between lifestyle behaviours and obesity in a multi-national study of children, and to investigate the influence of higher-order characteristics such as behavioural settings, and the physical, social and policy environments, on the observed relationships within and between countries.Methods/designThe targeted sample included 6000 10-year old children from 12 countries in five major geographic regions of the world (Europe, Africa, the Americas, South-East Asia, and the Western Pacific). The protocol included procedures to collect data at the individual level (lifestyle, diet and physical activity questionnaires, accelerometry), family and neighborhood level (parental questionnaires), and the school environment (school administrator questionnaire and school audit tool). A standard study protocol was developed for implementation in all regions of the world. A rigorous system of training and certification of study personnel was developed and implemented, including web-based training modules and regional in-person training meetings.DiscussionThe results of this study will provide a robust examination of the correlates of adiposity and obesity in children, focusing on both sides of the energy balance equation. The results will also provide important new information that will inform the development of lifestyle, environmental, and policy interventions to address and prevent childhood obesity that may be culturally adapted for implementation around the world. ISCOLE represents a multi-national collaboration among all world regions, and represents a global effort to increase research understanding, capacity and infrastructure in childhood obesity.

Canadian childhood obesity estimates based on WHO, IOTF and CDC cut-points

OBJECTIVE This article compares prevalence estimates of excess weight among Canadian children and youth according to three sets of body mass index (BMI) reference cut-points. The cut-points are based on growth curves generated by the World Health Organization (WHO), the International Obesity Task Force (IOTF), and the US Centers for Disease Control (CDC). A secondary objective is to compare estimates by method of data collection. METHODS Prevalence estimates of overweight and obesity were produced for 2- to 17-year-olds using the three sets of BMI cut-points. Estimates are based on data from 8 661 respondents from the 2004 Canadian Community Health Survey and 1 840 respondents from the 1978/79 Canada Health Survey. In both surveys, the height and weight of children were measured. RESULTS The 2004 prevalence estimate for the combined overweight/obese category is higher (35%) when based on the WHO cut-points compared with the IOTF (26%) or CDC (28%) cut-points. Estimates of the prevalence of obesity are similar based on WHO and CDC cut-points (13%), but lower when based on IOTF cut-points (8%). Absolute differences in excess weight estimates between 1978/79 and 2004 are similar based on the three sets of cut-points, but the relative increase is greater when based on the IOTF cut-points. Estimates vary substantially by method of data collection. CONCLUSION When interpreting prevalence estimates of overweight and obesity for children and youth, it is important to consider the definitions used and the method of data collection.

Health Risks, Correlates, and Interventions to Reduce Sedentary Behavior in Young People

CONTEXT Opportunities for young people to be sedentary have increased during leisure time, study time, and transportation time. PURPOSE This review paper focuses on sedentary behaviors among young people aged 2-18 years and includes evidence of the relationship between sedentary behavior and health risk indicators, an overview of public health recommendations, the prevalence of key sedentary behaviors, evidence of correlates of sedentary behavior and the effectiveness of interventions to reduce sedentary behaviors. EVIDENCE ACQUISITION Although this is a narrative style review and not systematic, where possible, findings from relevant review papers were summarized and a search of more recent literature was performed using computer-based databases such as PubMed, Google Scholar, ERIC, PsycINFO, Social Science Index, SportDiscus, and Health Reference Center - Academic. EVIDENCE SYNTHESIS Young people spend 2-4 hours per day in screen-based behaviors and 5-10 hours per day sedentary. Ethnicity, sociodemographic status, having a TV set in the bedroom, and parental behavior appear to be the most consistent correlates of TV viewing time; however, few recent studies aiming to reduce TV viewing or sedentary time among young people have been successful. CONCLUSIONS A growing body of evidence supports the development of public health recommendations to limit the time spent in screen-based behaviors. More research is needed to examine the prospective and experimental evidence of associations between overall sedentary time and health, determinants of sedentary behaviors other than screen-based behaviors, and interventions to reduce overall sedentary time or even alternative sedentary behaviors, such as transport- or education-related sitting time.

Canadian Physical Activity Guidelines for the Early Years (aged 0-4 years).

The Canadian Society for Exercise Physiology (CSEP), with assistance from multiple partners, stakeholders, and researchers, developed the first Canadian Physical Activity Guidelines for the Early Years (aged 0-4 years). These national guidelines were created in response to an urgent call from public health, health care, child care, and fitness practitioners for healthy active living guidance for the early years. The guideline development process was informed by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument and the evidence assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The recommendations are informed by evidence from a systematic review that examined the relationships between physical activity and health indicators (healthy body weight, bone and skeletal health, motor skill development, psychosocial health, cognitive development, and cardio-metabolic disease risk factors) for three age groups (infants aged <1 year; toddlers aged 1-2 years; preschoolers aged 3-4 years). The new guidelines include a preamble to provide context, followed by the specific recommendations. The final guidelines benefitted from an extensive on-line consultation process with input from over 900 domestic and international stakeholders, end-users, and key informants. The final guideline recommendations state that for healthy growth and development, infants (aged <1 year) should be physically active several times daily - particularly through interactive floor-based play. Toddlers (aged 1-2 years) and preschoolers (aged 3-4 years) should accumulate at least 180 min of physical activity at any intensity spread throughout the day, including a variety of activities in different environments, activities that develop movement skills, and progression toward at least 60 min of energetic play by 5 years of age. More daily physical activity provides greater benefits.

Associations Between Active School Transport and Physical Activity, Body Composition, and Cardiovascular Fitness: A Systematic Review of 68 Studies

BACKGROUND The impact of active school transport (AST) on daily physical activity (PA) levels, body composition and cardiovascular fitness remains unclear. METHODS A systematic review was conducted to examine differences in PA, body composition and cardiovascular fitness between active and passive travelers. The Medline, PubMed, Embase, PsycInfo, and ProQuest databases were searched and 10 key informants were consulted. Quality of evidence was assessed with GRADE and with the Effective Public Health Practice Project tool for quantitative studies. RESULTS Sixty-eight different studies met the inclusion criteria. The majority of studies found that active school travelers were more active or that AST interventions lead to increases in PA, and the quality of evidence is moderate. There is conflicting, and therefore very low quality evidence, regarding the associations between AST and body composition indicators, and between walking to/from school and cardiovascular fitness; however, all studies with relevant measures found a positive association between cycling to/from school and cardiovascular fitness; this evidence is of moderate quality. CONCLUSION These findings suggest that AST should be promoted to increase PA levels in children and adolescents and that cycling to/ from school is associated with increased cardiovascular fitness. Intervention studies are needed to increase the quality of evidence.

Physical Activity of Children: A Global Matrix of Grades Comparing 15 Countries

The Active Healthy Kids Canada (AHKC) Report Card on Physical Activity for Children and Youth has been effective in powering the movement to get kids moving by influencing priorities, policies, and practice in Canada. The AHKC Report Card process was replicated in 14 additional countries from 5 continents using 9 common indicators (Overall Physical Activity, Organized Sport Participation, Active Play, Active Transportation, Sedentary Behavior, Family and Peers, School, Community and Built Environment, and Government Strategies and Investments), a harmonized process and a standardized grading framework. The 15 Report Cards were presented at the Global Summit on the Physical Activity of Children in Toronto on May 20, 2014. The consolidated findings are summarized here in the form of a global matrix of grades. There is a large spread in grades across countries for most indicators. Countries that lead in certain indicators lag in others. Overall, the grades for indicators of physical activity (PA) around the world are low/poor. Many countries have insufficient information to assign a grade, particularly for the Active Play and Family and Peers indicators. Grades for Sedentary Behaviors are, in general, better in low income countries. The Community and Built Environment indicator received high grades in high income countries and notably lower grades in low income countries. There was a pattern of higher PA and lower sedentary behavior in countries reporting poorer infrastructure, and lower PA and higher sedentary behavior in countries reporting better infrastructure, which presents an interesting paradox. Many surveillance and research gaps and weaknesses were apparent. International cooperation and cross-fertilization is encouraged to tackle existing challenges, understand underlying mechanisms, derive innovative solutions, and overcome the expanding childhood inactivity crisis.