Prevention potential of risk factors for childhood overweight.

BACKGROUND In order to better target prevention initiatives for the obesity epidemic in Canada, policy-makers, in addition to information about risk factors, require an understanding of the preventive potential which is best provided by the risk factor's population attributable risk fraction (PARF). OBJECTIVE To estimate the PARF for childhood overweight risk factors as identified by a population-based study of elementary schoolchildren in Nova Scotia. METHODS Population-based survey data of Grade 5 students who participated in the 2003 Children's Lifestyle and School Performance Study in Nova Scotia, Canada, were linked to a provincial perinatal registry. PARFs were calculated from a parsimonious multilevel logistic regression model. RESULTS Physical activity, sedentary activity, maternal smoking during pregnancy, and maternal pre-pregnancy weight were considered potentially preventable. Sedentary activity (as estimated from time spent viewing TV, computers and video games or "screen time") and maternal pre-pregnancy weight appeared to offer the greatest potential for prevention. In total, approximately 40% of-overweight in childhood could potentially be prevented. CONCLUSION Excess screen time and maternal pre-pregnancy weight offer the greatest potential for prevention of childhood overweight at 11 years of age.