UC San Diego

Background

Improved understanding of sedentary time's impact on cardiometabolic health can help prioritize intervention targets.

Objective

We investigated cross-sectional and longitudinal relations of reported screen time and objectively measured total percent of time spent sedentary with cardiometabolic health in obese youth.

Methods

Participants were 106 obese adolescents age 11-13 (N = 106, 51% girls, and 82% Hispanic) recruited from primary care clinics in southern California. Main predictor measures were child-reported screen time and objectively assessed sedentary time. Outcome measures were body mass index (BMI), waist and hip circumference, body fat, blood pressure, glucose, triglycerides, insulin, cholesterol, aspartate aminotransferase (AST), and serum alanine aminotransferase (ALT).

Results

Total percent sedentary time was not associated with the cardiometabolic health markers after adjusting for moderate-to-vigorous physical activity (MVPA). However, screen time was positively associated with BMI and diastolic blood pressure at baseline, and positive longitudinal associations were found with BMI, triglycerides, low-density lipoprotein, AST, and ALT.

Conclusions

Reported screen time, but not total sedentary time, was related to multiple cardiometabolic health markers in obese adolescents, independent of MVPA. The findings suggest that limiting and replacing screen time, which was more than 3 hours per day on average in this sample, is likely an important behavior change strategy for interventions treating childhood obesity and comorbidities. The associations with screen time were strongest with AST and ALT, suggesting that this form of sedentary behavior may impact liver health.