Physical Activity, BMI, and Blood Pressure in US Youth: NHANES 2003-2006

Purpose: The objective of this study was to examine the independent and combined association of physical activity and body mass index (BMI) with blood pressure in youth. Methods: Youth aged 8-18 years from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) with BMI, blood pressure, and physical activity (accelerometer) were included in the analyses. A total of 2585 subjects (1303 males; 47% of all 8- to 18-year-olds) met these criteria. Results: Obese youth had a systolic blood pressure that was 8 mm Hg higher than normal weight youth. A significant interaction between BMI and physical activity on blood pressure was found (P < .001), and group differences among the BMI/activity groups showed that the 3 obese groups and the overweight/least active group had significantly higher systolic blood pressure than the normal weight/active group across all analyses. The overweight/least active and normal weight/least active groups had significantly higher diastolic blood pressure than the normal weight/active group as well. Conclusions: This study showed a significant independent and combined association of BMI and physical activity with blood pressure in youth. Interventions need to focus on the reduction of fatness/BMI as a way to reduce the cardiovascular risk in youth.