Potential for confounding of physical activity risk assessment by body weight and fatness.

Cross-sectional data from the second National Health and Nutrition Examination Survey (1976-1980) were used to study the association between body weight and fatness (assessed by body mass index, weight/height, and triceps skinfold thickness) and physical activity. It is concluded that relative body weight and fatness may be potential confounders of risk assessment analyses of physical activity.