Ian Janssen

New Canadian Physical Activity Guidelines

The Canadian Society for Exercise Physiology (CSEP), in cooperation with ParticipACTION and other stakeholders, and with support from the Public Health Agency of Canada (PHAC), has developed the new Canadian Physical Activity Guidelines for Children (aged 5-11xa0years), Youth (aged 12-17xa0years), Adults (aged 18-64xa0years), and Older Adults (aged >=65xa0years). The new guidelines include a preamble to provide context and specific guidelines for each age group. The entire guideline development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument, which is the international standard for clinical practice guideline development. Thus, the guidelines have gone through a rigorous and transparent developmental process; we based the recommendations herein on evidence from 3 systematic reviews, and the final guidelines benefitted from an extensive online and in-person consultation process with hundreds of stakeholders and key informants, both domestic and international. Since 2006, the products of our efforts resulted in the completion of 21 peer-reviewed journal articles (including 5 systematic reviews) that collectively guided this work. The process that Canadian researchers undertook to update the national physical activity guidelines represents the most current synthesis, interpretation, and application of the scientific evidence to date.

Canadian Sedentary Behaviour Guidelines for Children and Youth

The Canadian Society for Exercise Physiology (CSEP), in partnership with the Healthy Active Living and Obesity Research Group (HALO) at the Childrens Hospital of Eastern Ontario Research Institute, and in collaboration with ParticipACTION, and others, has developed the Canadian Sedentary Behaviour Guidelines for Children (aged 5-11xa0years) and Youth (aged 12-17xa0years). The guidelines include a preamble to provide context, followed by the specific recommendations for sedentary behaviour. The entire development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument, which is the international standard for clinical practice guideline development. Thus, the guidelines have gone through a rigorous and transparent developmental process and the recommendations are based on evidence from a systematic review and interpretation of the research evidence. The final guidelines benefitted from an extensive online consultation process with 230 domestic and international stakeholders and key informants. The final guideline recommendations state that for health benefits, children (aged 5-11xa0years) and youth (aged 12-17xa0years) should minimize the time that they spend being sedentary each day. This may be achieved by (i) limiting recreational screen time to no more than 2xa0h per dayxa0- lower levels are associated with additional health benefits; and (ii) limiting sedentary (motorized) transport, extended sitting time, and time spent indoors throughout the day. These are the first evidence-based Canadian Sedentary Behaviour Guidelines for Children and Youth and provide important and timely recommendations for the advancement of public health based on a systematic synthesis, interpretation, and application of the current scientific evidence.

Relationship between screen time and metabolic syndrome in adolescents

BACKGROUNDnThe primary objective was to determine the dose-response relation between screen time (television + computer) and the metabolic syndrome (MetS) in adolescents.nnnMETHODSnThe study sample included 1803 adolescents (12-19 years) from the 1999-04 US National Health and Nutrition Examination Surveys. Average daily screen time (combined television, computer and video game use) was self-reported. MetS was defined according to adolescent criteria linked to the adult criteria of the National Cholesterol Education Program (> or =3 of high triglycerides, high fasting glucose, high waist circumference, high blood pressure and low HDL cholesterol).nnnRESULTSnAfter adjustment for relevant covariates, the odds ratios (95% confidence intervals) for MetS increased in a dose-response manner (P(trend) < 0.01) across < or =1 h/day (1.00, referent), 2 h/day (1.21, 0.54-2.73), 3 h/day (2.16, 0.99-4.74), 4 h/day (1.73, 0.72-4.17) and > or =5 h/day (3.07, 1.48-6.34) screen time categories. Physical activity had a minimal impact on the relation between screen time and MetS.nnnCONCLUSIONSnScreen time was associated with an increased likelihood of MetS in a dose-dependent manner independent of physical activity. These findings suggest that lifestyle-based public health interventions for youth should include a specific component aimed at reducing screen time.

Distribution of Lipoproteins by Age and Gender in Adolescents

Background— The current National Cholesterol Education Program lipoprotein classification system for children and adolescents is recommended for use among 2- to 19-year-olds. This classification system does not take into account gender differences or the natural fluctuations in lipoprotein concentrations that occur with growth and maturation. Methods and Results— Data from the National Health and Nutrition Examination Surveys were used to develop age- and gender-specific thresholds that can be used to denote abnormal levels of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. Each curve was linked to the adult National Cholesterol Education Program Adult Treatment Panel III lipoprotein thresholds using LMS (Lambda-Mu-Sigma) growth curve regression methods. A series of growth curves and tables are presented that can be used to diagnose high-risk lipoprotein levels in the clinical and research settings. For example, in 1-year increments for males starting at age 12 and extending to age 19 years, the high-risk thresholds for total cholesterol were 6.03, 5.83, 5.70, 5.70, 5.77, 5.88, 6.02, and 6.16 mmol/L. The corresponding high-risk threshold for adults (≥20 years) is 6.22 mmol/L. Conclusions— The present study is the first attempt at developing age- and gender-specific lipoprotein threshold concentrations for adolescents. This new classification system should provide a more accurate diagnosis of high-risk lipoprotein levels and associated cardiovascular risks in adolescents.

Morbidity and Mortality Risk Associated With an Overweight BMI in Older Men and Women

Background: There is controversy as to whether older adults with a BMI in the overweight range (25 to 29.9 kg/m2) are at increased health risk and whether they should be encouraged to lose weight. The purpose of this study was to determine whether older adults with a BMI in the overweight range are at increased morbidity and mortality risk.

Dynapenic-Obesity and Physical Function in Older Adults

BACKGROUNDnDynapenia (low muscle strength) and obesity are associated with an impaired physical function. It was hypothesized that older individuals with both conditions (dynapenic-obesity) would have a more impaired physical function than individuals with dynapenia or obesity alone.nnnMETHODSnThis cross-sectional study included 2,039 men and women aged 55 years and older from the 1999-2002 National Health and Nutrition Examination Survey. Fat mass was measured by dual-energy x-ray absorptiometry and leg strength by dynamometer. Based on fat mass and leg strength tertiles, four independent groups were identified: non-dynapenic and non-obese, obese alone, dynapenic alone, and dynapenic-obese. An objective physical function measure was obtained from a 20-foot walking speed test, whereas subjective physical function measures were obtained from five self-reported questions.nnnRESULTSnWithin both sexes, the dynapenic-obese group had a slower walking speed than the non-dynapenic and non-obese and obese-alone groups (p <or= .01) but not the dynapenic-alone group. Similarly, with the exception of the dynapenic-alone group in men, the global subjective score was lower in the dynapenic-obese group than in the non-dynapenic and non-obese and obese-alone groups (p <or= .01). By comparison to the dynapenic-obese group, the adjusted odds ratios (95% confidence interval) for walking disability were 0.21 (0.12-0.35) in the non-dynapenic and non-obese, 0.34 (0.20-0.56) in the obese-alone, and 0.54 (0.33-0.89) in the dynapenic-obese groups. The corresponding odds ratios for a disability based on the global subjective score were 0.20 (0.09-0.42), 0.60 (0.30-1.21), and 0.41 (0.19-0.87).nnnCONCLUSIONnDynapenic-obesity was associated with a poorer physical function than obesity alone and in most cases with dynapenia alone.

Evolution of sarcopenia research

The term saropenia was coined by Irwin Rosenberg in 1989 to refer to age-related loss of skeletal muscle mass. The purpose of this current opinion is to provide an evolutionary overview of sarcopenia research since 1989. This includes the creation of an operational definition of sarcopenia; consideration of the impacts of sarcopenia on physical function, chronic disease, and mortality risk; the distinction between the process of sarcopenia and the process of age-related loss of muscle strength, a phenomenon that has recently been termed dynapenia; a comparison of the independent effects of sarcopenia and dynapenia on physical function, chronic disease, and mortality risk; and consideration of the combined influence of sarcopenia and dynapenia with obesity (i.e., sarcopenic-obesity and dynapenic-obesity) on physical function, chronic disease, and mortality risk.

Rural Canadian adolescents are more likely to be obese compared with urban adolescents.

OBJECTIVEnFew studies have examined variations in overweight and obesity by geographic location in youth. The purpose of this study was to investigate the association between urban/rural geographic status and being overweight or obese among Canadian adolescents.nnnMETHODSnThe study involved an analysis of a representative sample of 4851 Canadian adolescents in grades 6 to 10 from the 2001-02 Health Behaviour in School-aged Children Survey. Self-reports of participants demographics, physical activity, screen time, diet, and body mass index (BMI) were assessed. Adiposity status was determined using the international BMI thresholds for children and youth. Urban/rural status was coded on a five-point scale based on the geographic location of the participants schools. Logistic regression with generalized estimating equations to adjust for clustering was used to examine the association between urban/rural status and overweight/obesity.nnnRESULTSnThe population was 53.3% female with a mean age of 13.9 years (standard deviation, SD=1.5). Approximately 22.2% were living in rural areas while 14.4% were living in large metropolitan (metro) areas. After adjusting for age, sex, socioeconomic status, and Region of Canada, there was a trend for increasing overweight (p=0.001) and obesity (p=0.03) among adolescents as the level of rurality increased (relative odds for most urban to most rural regions for overweight or obese: 1.00, 0.98, 1.18, 1.57, 1.36; obesity: 1.00, 1.06, 1.39, 1.58, 1.56). Conclusion. This study provides new information about patterns of overweight/obesity among Canadian adolescents by urban-rural geographic status. These findings suggest that obesity prevention interventions should be particularly aggressive in rural areas.

Physical activity guidelines for children and youth.

The aim of this review is to provide a scientific update on evidence related to the biological and psycho-social health benefits of physical activity in school-aged children and youth. To accomplish this aim, the first part of the paper reviews existing physical activity guidelines for school-aged children and youth, with an emphasis placed on how Canadas guidelines compare and contrast with those of other countries and organizations. The paper then provides an overview of physical activity levels of Canadian children and youth, which indicates that few Canadian youngsters meet current physical activity recommendations. The next section of the paper summarizes the literature that informs how much physical activity is required to promote health and well-being in children and youth. The paper then provides suggestions on modifications that could be made to Canadas physical activity guidelines for children and youth. Specifically, consideration should be given to setting both minimal (> or =60 min/d) and optimal (up to several hours per day) physical activity targets. The final section identifies future research needs. In this section, a need is noted for comprehensive dose-response studies of physical activity and health in the paediatric age group.

ORIGINAL RESEARCH—ERECTILE DYSFUNCTION Abdominal Obesity and Physical Inactivity Are Associated with Erectile Dysfunction Independent of Body Mass Index

INTRODUCTIONnErectile dysfunction (ED) is common among men with an elevated body mass index (BMI). However, a high waist circumference (WC) and low levels of physical activity may predict ED independently of BMI.nnnAIMnWe investigated the independent relationships between BMI, WC, and physical activity with ED.nnnMETHODSnSubjects consisted of 3,941 adult men (age > or = 20 years) with no history of prostate cancer from the 2001-2004 National Health and Nutrition Examination Survey. Logistic regression analyses were used to examine the relative odds of ED association with categories of BMI, WC, and physical activity.nnnMAIN OUTCOME MEASURESnEstablished thresholds were used to divide subjects into three WC and BMI categories. Physical activity level was divided into active (> or =150 min/week), moderately active (30-149 min/week), and inactive (<30 min/week) categories. A single survey question was used to assess the presence of ED.nnnRESULTSnAfter control for potential confounders, men with either a high WC or an obese BMI had an approximately 50% higher odds of having ED compared with men with a low WC or a normal BMI, respectively. Further, moderately active or inactive men had an approximately 40-60% greater odds of ED compared with active men. When all three predictors (WC, BMI, and physical activity level) were entered into the same logistic regression model, both a high WC and low physical activity level (moderately active and inactive) were independently associated with a greater odds of ED, whereas BMI level was not.nnnCONCLUSIONnMaintaining a WC level below 102 cm and achieving the recommended amount of moderate-intensity physical activity (>or =150 min/week) is associated with the maintenance of proper erectile function, regardless of BMI level. These findings suggest that the clinical screening for ED risk should include the assessment of WC and physical activity level in addition to BMI.