Abstract
INTRODUCTION: Early childhood physical activity and sedentary behavior influence long-term health, yet evidence on interventions targeting how these behaviors are accumulated - rather than just total time - is limited. This study examined the impact of a parent-focused early childhood obesity prevention intervention on preschoolers' physical activity and sedentary behavior patterns. METHODS: This study is a secondary analysis of data from the Melbourne Infant Feeding, Activity and Nutrition Trial [InFANT] clustered randomized control trial (2008-2013). Physical activity and sedentary behavior data were gathered using ActiGraph™ GT1M accelerometers. To capture insights beyond total time and examine accumulation patterns, the duration and frequency of sedentary bouts [≤100 counts per minute (cpm)], light-intensity physical activity (101-1,680 cpm) bouts, and moderate- to vigorous-intensity physical activity (≥1,681 cpm) bouts, each lasting ≥1 min, as well as the total number of sedentary breaks, were calculated at each time point. The ≥1 min cut-offs for bout durations were defined based on the medians observed in this sample (0.50 min for sedentary, 0.47 min for light-, 0.25 min for moderate- to vigorous-intensity physical activity). Multilevel regression analyses were fitted to examine intervention effects at 19 months (T3), and 3.5 (T4) and 5 (T5) years of age. RESULTS: In total, 296, 144 and 140 participants had valid accelerometry data and were included in the analytical sample at T3, T4 and T5, respectively. The intervention had a significant and beneficial effect on the total amount of sedentary breaks at 3.5 (β[95%CI] = 10.9[2.98,18.91) and 5 years (β[95%CI] = 7.94[0.03,15.86). The intervention effects on all other outcomes were small and not significant. DISCUSSION: Whilst only effects on sedentary breaks were observed, this study suggests that interventions may impact accumulation patterns in children under five. TRIAL REGISTRATION: The Melbourne Infant Feeding, Activity and Nutrition Trial was registered with the International Standard Randomized Controlled Trial Number Register (ISRCTN81847050; 7/11/2007).