Body mass index trajectories of Indigenous Australian children and relation to screen time, diet, and demographic factors

OBJECTIVE: Limited cross‐sectional data indicate elevated overweight/obesity prevalence among Indigenous versus non‐Indigenous Australian children. This study aims to quantify body mass index (BMI) trajectories among Indigenous Australian children aged 3‐6 and 6‐9 years and to identify factors associated with the development of overweight/obesity. METHODS: Three‐year BMI change was examined in up to 1,157 children in the national Longitudinal Study of Indigenous Children. BMI trajectories among children with normal baseline BMI (n = 907/1,157) were quantified using growth curve models. RESULTS: Baseline prevalences of overweight/obesity were 12.1% and 25.4% among children of mean age 3 and 6 years, respectively. Of children with normal baseline BMI, 31.9% had overweight/obesity 3 years later; BMI increased more rapidly for younger versus older (difference: 0.59 kg/m(2)/year; 95% CI: 0.50‐0.69), female versus male (difference: 0.15 kg/m(2)/year; 95% CI: 0.07‐0.23), and Torres Strait Islander versus Aboriginal (difference: 0.36 kg/m(2)/year; 95% CI: 0.17‐0.55) children. Results were consistent with less rapid rates of BMI increase for children with lower sugar‐sweetened beverage (including fruit juice) and high‐fat food consumption. Children's BMI was lower in more disadvantaged areas. CONCLUSIONS: Overweight/obesity is common, and increases rapidly, in early childhood. Interventions are required to reduce the overweight/obesity prevalence among Indigenous Australian children in the first 3 years of life and to slow the rapid overweight/obesity onset from age 3 to 9 years.