Outdoor Time and Metabolically Healthy Obesity in Children

Abstract

A large proportion of children are recognized as metabolically healthy obese (MHO) and present a favorable cardio-metabolic profile. However, the contribution of outdoor time physical activity (PA) to the MHO phenotype is unknown. PURPOSE: To investigate the association between outdoor time PA and the MHO phenotype in children. METHODS: An analysis of overweight and obese children aged 6-14 (n=386) from the Canadian Health Measures Survey (cycles 3-4) was performed. Outdoor time PA (hours/week) was self-reported using a series of questions in relation to the school schedule, such as: “during the past month, on an average school day, how much time did you usually spend outside?” Participants were given a score of 0-5 based on their response: 0 min. (0); 1 to <15 mins. (1); 15 to <30 mins. (2); 30 to <1 hour (3); 1 to <2 hours (4); and ≥2 hours (5). Then, a computed score, ranging from 0-25, was created for outdoor time PA. MHO status was determined based on the absence of cardio-metabolic risk factors including: triglycerides, HDL-cholesterol, systolic or diastolic blood pressure, and glucose (MHO: 0 cardio-metabolic risk factors; non-MHO: ≥1 cardio-metabolic risk factors). Multiple logistic regression analyses for the likelihood of MHO were adjusted for age, sex, socioeconomic status, and moderate-to-vigorous PA (MVPA) intensity. RESULTS: The proportion of MHO children was 58.5%. No significant differences were observed between MHO and non-MHO according to outdoor time PA, sedentary time, or MVPA (p>0.05). Logistic regressions indicated that outdoor time PA was not significantly associated with the MHO phenotype (OR: 0.99, 95% CI=0.92-1.05; p=0.69), while MVPA was significantly associated with the MHO phenotype (OR: 1.01, 95% CI=1.00-1.02; p=0.03). CONCLUSIONS: Outdoor time PA is not associated with the MHO phenotype. Children are more likely to be MHO with greater amounts of MVPA, regardless of whether these activities are completed outdoors or indoors.