Equivalence Curves for Healthy Lifestyle Choices

In this population-based cohort of 1179 children 11 to 12 years of age, equivalent benefits to adiposity and HRQoL were associated with different changes (trade-offs) in activities. BACKGROUND Understanding equivalence of time-use trade-offs may inform tailored lifestyle choices. We explored which time reallocations were associated with equivalent changes in children’s health outcomes. METHODS Participants were from the cross-sectional Child Health CheckPoint Study (N = 1181; 11–12 years; 50% boys) nested within the population-based Longitudinal Study of Australian Children. Outcomes were adiposity (bioelectrical impedance analysis, BMI and waist girth), self-reported health-related quality of life (HRQoL; Pediatric Quality of Life Inventory), and academic achievement (standardized national tests). Participants’ 24-hour time use (sleep, sedentary behavior, light physical activity, and moderate-to-vigorous physical activity [MVPA]) from 8-day 24-hour accelerometry was regressed against outcomes by using compositional log-ratio linear regression models. RESULTS Children with lower adiposity and higher HRQoL had more MVPA (both P < .001) and sleep (P = .002; P = .008), and less sedentary time (P = .02; P = .001) and light physical activity (P < .001; P = .04), each relative to remaining activities. Children with better academic achievement had more sedentary time (P = .03) and less light physical activity (P = .006), each relative to remaining activities. A 0.1 standardized decrease in adiposity was associated with either 55 minutes more sleep, 89 minutes less sedentary time, 34 minutes less light physical activity, or 19 minutes more MVPA. A 0.1 standardized increase in HRQoL was associated with either 64 minutes more sleep, 65 minutes less sedentary time, 72 minutes less light physical activity, or 29 minutes more MVPA. CONCLUSIONS Equivalent differences in outcomes were associated with several time reallocations. On a minute-for-minute basis, MVPA was 2 to 6 times as potent as sleep or sedentary time.