Higher self-reported physical activity Is associated with lower systolic blood pressure: The Dietary Intervention Study in Childhood (DISC)

Objective: Children participating in a dietary clinical trial were studied to assess physical activity patterns in boys and girls longitudinally from late childhood through puberty; and to determine the association of level of physical activity on systolic blood pressure (SBP), low density lipoprotein (LDL) cholesterol, and body mass index (BMI). Patients and Methods: In the Dietary Intervention Study in Childhood (DISC), a randomized clinical trial of a reduced saturated fat and cholesterol diet in 8-10 year olds with elevated LDL, a questionnaire that determined time spent in five intensity levels of physical activity was completed at baseline and at 1 and 3 years. A MET score was calculated for weekly activity; hours per week were calculated for intense activities. We hypothesized that weekly self-reported physical activity would be associated with lower SBP, LDL, and BMI over three years. Longitudinal data analyses were performed for each outcome (SBP, LDL, and BMI) using generalized estimating equations with MET score per week as the independent variable adjusted for visit, gender, and Tanner stage (BMI was included in models for SBP and LDL). Results: The initial study cohort comprised 663 youths (362 male; age 9.7 years, 301 female; age 9.0 years) of whom 623 (94%) completed the 3-year visit. For every 100 MET-hours of physical activity, there was a decrease of 1.15 mmHg of SBP (p=0.0038). There was a 1.28 mg/dl decline in LDL (p=0.10) for a similar energy expenditure. For BMI, an analysis of intense physical activity showed that for every 10 hours of intense activity, there was a trend toward significance with a 0.2 kg/m2 decrease (p=0.06). Conclusion: Children with elevated cholesterol who lead a more physically active lifestyle have lower SBP and a trend toward lower LDL over a 3-year interval. Long-term participation in intense physical activity may reduce BMI as well