Behavioural and Environmental Factors Associated with Body Mass Index during Adolescence

Abstract

The growing prevalence of overweight and obesity in adolescents is of great concern. The objective of this research was to assess the relationship between body mass index (BMI) and individual factors such as: dietary intake, physical activity and sedentary behaviours; and to assess the relationship between BMI and interpersonal factors such as: food availability and encouragement of activity. A web-based survey of physical activity and nutrition (WebSPAN2) was completed by 4360 adolescents in grades 7 to10 in Alberta. Results from this study suggest that gender and grade level contributed significantly to BMI. Insufficient physical activity and extended periods of time spent in sedentary behaviours were the only modifiable risk factors associated with a higher BMI of adolescents. The variable, ‘nutrition beliefs’ was positively associated with BMI. Cohort studies are required to clarify the relative importance of individual and interpersonal factors on BMI during adolescence.