Patterns in Sedentary Time and Cardio-Metabolic Risk in Children: A meta-analysis in the International Children’s Accelerometry Database (ICAD)

Background: Observational studies and lab-based trials indicated protective effects of regularly interrupting sedentary time on cardio-metabolic health in adults. We examined associations of breaks in sedentary time with cardio-metabolic risk in children.

Methods: We included 19,520 children (aged 4-18, 48% boys) from 14 studies participating in ICAD, providing data on cardio-metabolic risk (at least waist circumference). Total and breaks in sedentary time (100 counts/minute cut-off) and moderate-to-vigorous physical activity (≥3000 counts/minute, MVPA) were measured by ActiGraph and processed centrally (1 minute epoch; ≥1 valid day (≥10 wear hours/day); non-wear bout: ≥60 minutes consecutive zeros, terminated at third non-zero interruption). Outcomes were objectively-assessed waist circumference (WC); blood pressure (BP, systolic, diastolic); triglycerides; HDL-cholesterol; fasting glucose; fasting insulin; and clustered cardio-metabolic risk. Within-study multiple linear regression analysis and random effects meta-analysis (I2 for heterogeneity) examined cross-sectional associations between breaks in sedentary time and each outcome variable, adjusting for age, sex, sedentary, MVPA and total monitor wear time. Additional adjustment for WC examined a mediation effect by central adiposity.

Results: More breaks in sedentary time were independently associated with lower WC (cm; unstandardised beta (95%CI) per 10 breaks/day: -0.18 (-0.29, -0.08)) and systolic BP: (mmHg; -0.14 (-0.25, -0.02)), but no other outcomes. WC mediated the association with systolic BP.

Conclusions: These findings suggest a potential protective effect of regularly interrupting sedentary time on specific cardio-metabolic biomarkers in children. Further longitudinal research, with accurate sedentary pattern characterization, needs to elucidate the beneficial role and clinical significance of regularly interrupting sitting in this age group.