Prevalence of Overweight in Children Starts Early in Life: Findings From the Italian NASCITA Birth Cohort Study

To estimate the prevalence of overweight at 36 months of age and that of persistent overweight in an Italian birth cohort and to identify factors related to an increased likelihood of having overweight.

The Italian NASCITA birth cohort was analysed. Children were classified in the underweight, normal or overweight range at 12, 24 and 36 months of age according to the World Health Organization percentiles, and the prevalence of overweight (≥ 85th centile) was estimated. Persistent overweight was defined as having overweight in all three assessments. To test the association between the chance of having overweight, and parental and child characteristics, healthy newborns with appropriate for gestational age birth weight were selected, and univariate and multivariate analyses were performed.

The prevalence of overweight was 22.7% at 12 months of age and 21.2% at 36 months (chi square-for-trend = 1.5 and p = 0.21). In all, 8.8% of the children had persistent overweight. Overweight at 12 months (RR: 3.28 and 95% CI: 2.69-4.00) and a big appetite (RR: 2.00 and 95% CI: 1.59-2.52) were the main factors associated with greater likelihood of overweight at 36 months, while excessive appetite and frequency of interaction with electronic devices were the main determinants of persistent overweight.

The body mass index status at 12 months greatly influenced that at 36 months. The increased risk of persistent overweight in children interacting with electronic devices suggests that extreme caution in allowing preschool children to use smartphone or tablets should be adopted. Furthermore, nutritional education of the entire family is essential to appropriately guide children's appetite.