Objectively measured sedentary time and physical activity levels in a sample of pre-school children: amounts and obesity risk.

Objective: Sedentary behaviours, even at an early age, are associated with potential health risks such as obesity, some cardio metabolic risk factors, poorer mental health, and lower levels physical fitness. The aim of this study was twofold: i) to compare objectively measured sedentary time and physical activity (PA) levels in its different intensity portions between boys and girls; ii) to analyse associations among the risk of overweight and moderate-to-vigorous physical activity (MVPA) in pre-school children.

Methods: The present cross-sectional study comprised a sample of 134 children (70 males) aged 3-5 years. Height and weight were measured, and BMI was calculated. A tri-axial accelerometer was used to obtain seven consecutive days of MVPA, as well as the weekly time being sedentary. The t-test was used to analyse the effect of the sex on body size, sedentary behaviour, and PA levels; furthermore, logistic regression analysis was used to examine the afore-mentioned relationship among the risk of obesity and MVPA, controlling for sex, age, and sedentary behaviour.

Results: About 16.0% of the sample is overweight or obese (boys 12.2%, girls 20.0%). Boys spent significantly more minutes/day in the moderate-to-vigorous portion of PA than their female counterparts on the week days (boys: 90.9±21.8 min/day; girls: 77.6±21.7 min/day) and in the total measured days (boys: 89.5±20.4 min/day; girls: 77.7±21.6 min/day). MVPA was inversely associated with the risk of being overweight in pre-school children after adjustment for potential confounders; children with higher levels of MVPA have less likely to be classified as overweight and/or obese than less active children (95% CI 0.96 to 0.99, p<0.05).

Conclusions: Findings of this study revealed males significantly more active than females. Objectively measured MVPA was independent and inversely associated with increased risk of overweight in pre-school children. Future interventions for improving weight health in paediatrics should enhance MVPA at early ages.