Physical Activity and BMI: Evidence From the Panel Study of Income Dynamics Child Development Supplement

BACKGROUND: This study assessed the association between amount of physical activity and body mass index (BMI) percentile among middle and high school children. Total daily physical activity needs to include both in and out of school physical activity. METHODS: A secondary data analysis was performed on 1306 children drawn from the Panel Study of Income Dynamics Child Development Supplement (CDS III, 2007). The dependent variable in this study was BMI percentile, while the independent variable was physical activity. The multinomial logistic regression model was used to assess the associations between physical activity and BMI percentile controlling for age, gender, race/ethnicity, parental income, and neighborhood safety. RESULTS: Children who engaged in low daily physical activity levels had 1.8 times the odds of being obese versus normal weight than those who engaged in moderate levels [odds ratio (OR) = 1.80, confidence interval (CI) = 1.31, 2.48]. African-American children had 1.6 times the odds of being obese than normal weight (OR = 1.55, CI = 0.99, 2.43) and Hispanic children had approximately 1.8 times the odds of being obese than normal weight in comparison to non-Hispanic white children (OR = 1.79, CI = 1.00, 3.21). Females had about 1.5 times the odds of being overweight than normal weight than males (OR = 1.49, CI = 1.04, 2.13). CONCLUSIONS: This study suggests that the accumulation of 30 minutes or more of daily physical activity may be effective in decreasing obesity prevalence among middle and high school-aged children.