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The association between physical activity, fitness and insulin sensitivity in a cohort of school-aged children with an obese parent
abstract
weight for children has not been studied extensively and the results to date have been inconsistent. Methods: Data are from the 2007-2009 Canadian Health Measures Survey (CHMS). Parent-reported height and weight of children aged 6-11 years (n=826) was obtained. Subsequently, the children’s height and weight were directly measured by trained health measures specialists. results: On average, parents underestimated both the height (3.4 cm) and weight (1.1 kg) of their children. Estimates of the prevalence of obesity were significantly higher when based on parent-reported versus measured values for children aged six to eight years, but the two collection modes resulted in similar estimates of obesity for children aged nine to 11 years. For children in both age groups, there were substantial misclassification errors by body mass index (BMI) category when based on parent-reported values. This resulted in diminished associations between obesity and other variables such as aerobic fitness and systolic blood pressure. conclusions: Bias associated with parental reports of children’s height and weight results in misclassification errors for obesity that in turn affect relationships with other variables. This analysis suggests direct measures are required to accurately determine obesity estimates and their relationships with health indicators in children. 15 What drives the change in body Mass Index over a 14-year period? a panel data analysis K.Thavorn1, A.Laporte2, and P.C.Coyte3 1 Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; 2Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; 3Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada Introduction: Over the past decade, the prevalence of obesity has increased in Canada. Existing evidence suggests that a reduction in physical activity, a change in food intake, and genetic predisposition are the main determinants of obesity. Yet, little is known about factors that account for the temporal variations in an individual body mass index (BMI). This paper will identify the determinants of obesity, with particular attention to the effect of immigration status, racial/ethnicity, and their joint association with others socio-demographic factors on BMI over a 14-year period. Methods: Data was acquired from the longitudinal data set of the National Population Health Survey (NPHS), a longitudinal cohort of 17,000 individuals followed every two years from 1994 to 2009. The effects of immigration status, lifestyle behaviour, food prices, and socioeconomic status on BMI over eight survey cycles were assessed using a panel data analysis. results: Preliminary analysis reveals that recent immigrants reported lower BMIs than long-term immigrants, and the Canadian-born population. After adjusting for age, food prices, and health status, longer duration in Canada, being white, lower household income, less physical activity and less fruit/vegetables consumed were found to be associated with an increase in BMI. conclusions: Obesity is not only associated with immigration status and race/ethnicity that may reflect genetic predispositions, but it is also accounted for by unhealthy diet and lifestyle behaviours. This finding should be taken into account in the formulation of health policies to target obesity prevention to specific subpopulations. 16 the association between physical activity, fitness and insulin sensitivity in a cohort of school-aged children with an obese parent M. Henderson1, K. Gray-Donald2, M.E. Mathieu3, J. Hanley4, R. Rabasa-Lhoret5, and M. Lambert6 1 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; 2Department of Dietetics
and Human Nutrition, McGill University, Montreal, Quebec, Canada; 3 Department of Kinesiology, Université de Montréal, and CHU Sainte-Justine, Montréal, Québec, Canada; 4Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; 5Dpartment of Nutrition, Université de Montréal, and Diabetes Research Center (MDRC), Centre Hospitalier de l’Université de Montréal (CHUM), and Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada; 6Department of Pediatrics, CHU Sainte-Justine and Université de Montréal, Montréal, Québec, Canada. Introduction: Our objective was to examine the association between physical activity (PA) and fitness on insulin sensitivity (IS); to determine whether these relationships differed across sexes, and to assess whether there was an interaction between PA and fitness. Methods: Baseline data were obtained from the QUALITY cohort, an ongoing longitudinal cohort of 632 Caucasian youth, aged eight to 10 years at recruitment, with at least one obese biological parent. IS was measured by two fasting indices, insulin and HOMA-IR, and an OGTT-based index, Matsuda ISI. Fitness was measured by VO2 peak; PA was measured over seven days using an accelerometer (counts per minute). Potential confounders included age, sex, fat mass index [FMI=total body fat measured by DXA (kg)/height (m)2] and Tanner stage (pre-pubertal/pubertal). results: Increasing fitness levels were associated with improved IS as measured by Matsuda ISI (p=0.022), but not with HOMA-IR or fasting insulin. PA was not associated with IS after controlling for age, sex, fitness, Tanner stage, and FMI. Increasing age and FMI predicted poorer IS across all measures. Girls tended to have poorer IS as measured by Matsuda-ISI. We found no significant interaction between sex and fitness, sex and PA, or fitness and PA. conclusions: In children with an obese parent, fitness is associated with improved IS measured by the OGTT derived measure of IS, independently of PA, age, FMI, Tanner stage, and sex. PA did not appear to be an independent predictor of IS. Longitudinal studies are required to assess how these associations change over time. 17 short sleep duration is independently associated with overweight and obesity in canadian children J.P. Chaput1, M. Lambert2, K. Gray-Donald3, J.J. McGrath4, M.S. Tremblay1, J. O’Loughlin5, and A. Tremblay6 1 Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada; 2Department of Pediatrics, CHU Ste-Justine and University of Montreal, Montreal, Quebec, Canada; 3School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, Canada; 4 Department of Psychology, Concordia University, Montreal, Quebec, Canada; 5Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada; 6Division of Kinesiology, Laval University, Quebec City, Quebec, Canada. Objective: To investigate the association between sleep duration and obesity. Methods: The Quebec Adiposity and Lifestyle Investigation in Youth (QUALITY) study is a longitudinal investigation of Caucasian children who have at least one obese biological parent. Children (n=550, mean (SD) age: 9.6 (0.9) years who provided complete data at baseline were included in the analyses. Objective measures of adiposity (BMI z-score, waist circumference and per cent body fat measured by dualenergy X-ray absorptiometry), sleep duration, and physical activity (accelerometer over seven days), and diet (24-hour food recalls) were collected. The children were categorized into four groups according to their sleep duration: <10 hours, 10-10.9 hours, 11-11.9 hours, and ≥12 hours of sleep per night. results: We observed a U-shaped relationship between sleep duration and all adiposity indices. However, dietary and physical activity indicators did not significantly differ between sleep categories, including macronutrient intake, snacking, screen time, and physical activity
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weight for children has not been studied extensively and the results to date have been inconsistent. Methods: Data are from the 2007-2009 Canadian Health Measures Survey (CHMS). Parent-reported height and weight of children aged 6-11 years (n=826) was obtained. Subsequently, the children’s height and weight were directly measured by trained health measures specialists. results: On average, parents underestimated both the height (3.4 cm) and weight (1.1 kg) of their children. Estimates of the prevalence of obesity were significantly higher when based on parent-reported versus measured values for children aged six to eight years, but the two collection modes resulted in similar estimates of obesity for children aged nine to 11 years. For children in both age groups, there were substantial misclassification errors by body mass index (BMI) category when based on parent-reported values. This resulted in diminished associations between obesity and other variables such as aerobic fitness and systolic blood pressure. conclusions: Bias associated with parental reports of children’s height and weight results in misclassification errors for obesity that in turn affect relationships with other variables. This analysis suggests direct measures are required to accurately determine obesity estimates and their relationships with health indicators in children. 15 What drives the change in body Mass Index over a 14-year period? a panel data analysis K.Thavorn1, A.Laporte2, and P.C.Coyte3 1 Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; 2Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada; 3Department of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada Introduction: Over the past decade, the prevalence of obesity has increased in Canada. Existing evidence suggests that a reduction in physical activity, a change in food intake, and genetic predisposition are the main determinants of obesity. Yet, little is known about factors that account for the temporal variations in an individual body mass index (BMI). This paper will identify the determinants of obesity, with particular attention to the effect of immigration status, racial/ethnicity, and their joint association with others socio-demographic factors on BMI over a 14-year period. Methods: Data was acquired from the longitudinal data set of the National Population Health Survey (NPHS), a longitudinal cohort of 17,000 individuals followed every two years from 1994 to 2009. The effects of immigration status, lifestyle behaviour, food prices, and socioeconomic status on BMI over eight survey cycles were assessed using a panel data analysis. results: Preliminary analysis reveals that recent immigrants reported lower BMIs than long-term immigrants, and the Canadian-born population. After adjusting for age, food prices, and health status, longer duration in Canada, being white, lower household income, less physical activity and less fruit/vegetables consumed were found to be associated with an increase in BMI. conclusions: Obesity is not only associated with immigration status and race/ethnicity that may reflect genetic predispositions, but it is also accounted for by unhealthy diet and lifestyle behaviours. This finding should be taken into account in the formulation of health policies to target obesity prevention to specific subpopulations. 16 the association between physical activity, fitness and insulin sensitivity in a cohort of school-aged children with an obese parent M. Henderson1, K. Gray-Donald2, M.E. Mathieu3, J. Hanley4, R. Rabasa-Lhoret5, and M. Lambert6 1 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; 2Department of Dietetics
and Human Nutrition, McGill University, Montreal, Quebec, Canada; 3 Department of Kinesiology, Université de Montréal, and CHU Sainte-Justine, Montréal, Québec, Canada; 4Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; 5Dpartment of Nutrition, Université de Montréal, and Diabetes Research Center (MDRC), Centre Hospitalier de l’Université de Montréal (CHUM), and Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada; 6Department of Pediatrics, CHU Sainte-Justine and Université de Montréal, Montréal, Québec, Canada. Introduction: Our objective was to examine the association between physical activity (PA) and fitness on insulin sensitivity (IS); to determine whether these relationships differed across sexes, and to assess whether there was an interaction between PA and fitness. Methods: Baseline data were obtained from the QUALITY cohort, an ongoing longitudinal cohort of 632 Caucasian youth, aged eight to 10 years at recruitment, with at least one obese biological parent. IS was measured by two fasting indices, insulin and HOMA-IR, and an OGTT-based index, Matsuda ISI. Fitness was measured by VO2 peak; PA was measured over seven days using an accelerometer (counts per minute). Potential confounders included age, sex, fat mass index [FMI=total body fat measured by DXA (kg)/height (m)2] and Tanner stage (pre-pubertal/pubertal). results: Increasing fitness levels were associated with improved IS as measured by Matsuda ISI (p=0.022), but not with HOMA-IR or fasting insulin. PA was not associated with IS after controlling for age, sex, fitness, Tanner stage, and FMI. Increasing age and FMI predicted poorer IS across all measures. Girls tended to have poorer IS as measured by Matsuda-ISI. We found no significant interaction between sex and fitness, sex and PA, or fitness and PA. conclusions: In children with an obese parent, fitness is associated with improved IS measured by the OGTT derived measure of IS, independently of PA, age, FMI, Tanner stage, and sex. PA did not appear to be an independent predictor of IS. Longitudinal studies are required to assess how these associations change over time. 17 short sleep duration is independently associated with overweight and obesity in canadian children J.P. Chaput1, M. Lambert2, K. Gray-Donald3, J.J. McGrath4, M.S. Tremblay1, J. O’Loughlin5, and A. Tremblay6 1 Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada; 2Department of Pediatrics, CHU Ste-Justine and University of Montreal, Montreal, Quebec, Canada; 3School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, Canada; 4 Department of Psychology, Concordia University, Montreal, Quebec, Canada; 5Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada; 6Division of Kinesiology, Laval University, Quebec City, Quebec, Canada. Objective: To investigate the association between sleep duration and obesity. Methods: The Quebec Adiposity and Lifestyle Investigation in Youth (QUALITY) study is a longitudinal investigation of Caucasian children who have at least one obese biological parent. Children (n=550, mean (SD) age: 9.6 (0.9) years who provided complete data at baseline were included in the analyses. Objective measures of adiposity (BMI z-score, waist circumference and per cent body fat measured by dualenergy X-ray absorptiometry), sleep duration, and physical activity (accelerometer over seven days), and diet (24-hour food recalls) were collected. The children were categorized into four groups according to their sleep duration: <10 hours, 10-10.9 hours, 11-11.9 hours, and ≥12 hours of sleep per night. results: We observed a U-shaped relationship between sleep duration and all adiposity indices. However, dietary and physical activity indicators did not significantly differ between sleep categories, including macronutrient intake, snacking, screen time, and physical activity
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