Objectively Measured Physical Activity and Body Mass Index in Preschool Children

Aim. To examine the association between objectively measured physical activity (PA) and body mass index (BMI) in preschool children. Methods. The study comprised 281 children (55.9% boys) aged from 4 to 6 years. PA was measured by accelerometer. Children were categorized as non-overweight (NOW) and overweight/obese (OW) according to the sex-adjusted BMI z-score (<1 and >/=1, resp.). Results. Total and moderate intensity PA were not associated with BMI. We observed that a higher proportion of OW children were classified as low-vigorous PA compared to their NOW peers (43.9 versus 32.1%, resp., P > .05). Logistic regression analysis showed that children with low-vigorous PA had higher odds ratio (OR) to be classified as OW compared to those with high-vigorous PA (OR = 4.4; 95% CI: 1.4-13.4; P = .008) after adjusting for BMI at first and second years of life and other potential confounders. Conclusion. The data suggests that vigorous PA may play a key role in the obesity development already at pre-school age.