The Interactive Effects of Sedentary Time, Physical Activity, and Fat Mass on Insulin Resistance in the Young Population

Context Recent evidence in 9-year-old children with overweight/obesity followed up for 7 years until late adolescence concluded that increased physical activity (PA) decreased the risk of high fasting glucose, low insulin sensitivity, and secretion. However, whether this effect persists until young adulthood is unknown.Objective This observational study examined the effects of cumulative sedentary time (ST), light PA (LPA), and moderate to vigorous (MVPA) on glucose, insulin, and homeostatic model assessment for insulin resistance (HOMA-IR) in 11-year-old children followed up for 13 years until young adulthood.Methods Altogether 792 children from the Avon Longitudinal Study of Parents and Children, UK, who had data on at least 2 measures of accelerometer-based movement behaviour during 11-, 15-, and 24-year follow-up clinic visits with complete fasting glucose, insulin, and HOMA-IR measures at ages 15, 17, and 24 years were included. ST, LPA, and MVPA were measured with an accelerometer.Results Cumulative ST from ages 11-24 years was associated with increased odds (odds ratio 1.20, 95% CI 1.00-1.44, P = .047) and cumulative LPA was associated with the decreased odds of hyperinsulinemia (0.80, 0.66-0.96, P = .017) among participants with overweight/obesity. Cumulative MVPA was inversely associated with insulin but after accounting for the mediating role of fat mass, MVPA effect on lowering insulin decreased by 58% resulting in statistical nonsignificance. In the temporal path analyses, among participants with overweight/obesity, higher glucose at age 15 years was associated with lower LPA and MVPA at 24 years. Higher LPA at 15 years was associated with lower insulin and HOMA-IR at 24 years and vice versa.Conclusion Promoting LPA while decreasing body fat mass and ST may be considered crucial intervention targets to attenuate the risk of hyperinsulinemia and insulin resistance from childhood through young adulthood.