Associations between sedentary behavior and blood pressure in young children.

OBJECTIVE To examine the effect of sedentary behavior on blood pressure (BP) in young children using different indicators of sedentariness. DESIGN Cross-sectional study. SETTING A rural Midwestern US community. PARTICIPANTS Children aged 3 to 8 years (N = 111). Intervention Adiposity was assessed using dual energy x-ray absorptiometry. Objective measurements of sedentary activity were obtained from the accelerometers that participants wore continuously for 7 days. Measurements of television (TV) viewing, computer, and screen time (TV + computer) were obtained via parent report. MAIN OUTCOME MEASURES Systolic and diastolic BP. RESULTS The sample spent a mean of 5 hours per day in sedentary activities, of which 1.5 hours were screen time. Accelerometer-determined sedentary activity was not significantly related to systolic BP or diastolic BP after controlling for age, sex, height, and percentage of body fat. However, TV viewing and screen time, but not computer use, were positively associated with both systolic BP and diastolic BP after adjusting for potential confounders. Participants in the lowest tertile of TV and screen time had significantly lower levels of systolic and diastolic BP than participants in the upper tertile. CONCLUSIONS Sedentary behaviors, particularly TV viewing and screen time, were associated with BP in children, independent of body composition. Other factors that occur during excessive screen time (eg, food consumption) should also be considered in the context of sedentary behavior and BP development in children.