Isotemporal Substitution Models For Associations Between PA And Health Outcomes In Overweight/obese Adults

Abstract

PURPOSE: Purpose: To examine the effects of reallocating sitting time to moderate- or vigorous-intensity physical activity on health outcomes in a population-representative sample of overweight/obese Korean adults. METHODS: Data were retrieved from a subsample (N=1,420; Age=52.35±16.64yrs; BMI=27.57±2.37) of the KNHANES 2014. Time spent on moderate-intensity physical activity (MPA), vigorous-intensity physical activity (VPA), and sitting (ST) were measured utilizing the GPAQ. Health outcomes were 1) the metabolic syndrome (having 3+ risk components: elevated fasting glucose, central obesity, systemic hypertension, elevated triglycerides, and low HDL-C, defined according to AHA/NHLBI criteria), and 2) self-reported health measured by the EuroQol-5D Questionnaire (EQ5D; count variable). Age-group-specific (i.e., middle-age vs. older adults) Logistic and Poisson regression models were used to determine the associations when substituting a specific amount of ST with an equal amount of MPA, and VPA, respectively on metabolic and self-reported health outcomes. Analyses were adjusted for gender, smoking, drinking, education, and household incomes. RESULTS: In middle aged (30-64yrs), replacing ST with an equal amount of time in VPA was significantly associated with reduced odds for self-reported health problems (OR=0.86, 95%CI:0.76-0.98). Similarly, in older adults (65+yrs), substituting sitting time with MPA was significantly associated with lower odds for self-reported health problems (OR=0.96, 95%CI:0.92-0.99). In opposite, replacing ST with MPA or VPA was not associated with the metabolic syndrome. CONCLUSIONS: Substituting sitting time with VPA or MPA appears beneficially associated with self-reported health in overweight/obese middle-aged and elderly Korean men and women, respectively. The different associations between age groups may be explained by low participation in VPA in the older age-group. *This study was supported by NRF-2014R1A1A3049992. Corresponding: Miyoung Lee