1. ¹College of Kinesiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
2. ²Canadian Research Institute for Social Policy, University of New Brunswick, Fredericton, New Brunswick, Canada

Correspondence: MS Tremblay, College of Kinesiology, University of Saskatchewan, 105 Gymnasium Place, Saskatoon, Saskatchewan, Canada S7N 5C2. E-mail: mark.tremblay@usask.ca

Received 12 September 2002; Revised 3 April 2003; Accepted 4 April 2003.

Abstract

OBJECTIVE: This study examined the relation among children's physical activity, sedentary behaviours, and body mass index (BMI), while controlling for sex, family structure, and socioeconomic status.

DESIGN: Epidemiological study examining the relations among physical activity participation, sedentary behaviour (video game use and television (TV)/video watching), and BMI on a nationally representative sample of Canadian children.

SUBJECTS: A representative sample of Canadian children aged 7–11 (N=7216) from the 1994 National Longitudinal Survey of Children and Youth was used in the analysis.

MEASUREMENTS: Physical activity and sport participation, sedentary behaviour (video game use and TV/video watching), and BMI measured by parental report.

RESULTS: Both organized and unorganized sport and physical activity are negatively associated with being overweight (10–24% reduced risk) or obese (23–43% reduced risk), while TV watching and video game use are risk factors for being overweight (17–44% increased risk) or obese (10–61% increased risk). Physical activity and sedentary behaviour partially account for the association of high socioeconomic status and two-parent family structure with the likelihood of being overweight or obese.

CONCLUSION: This study provides evidence supporting the link between physical inactivity and obesity of Canadian children.