The national, longitudinal NASCITA birth cohort study: prevalence of overweight or obesity at 12 months of age in children born healthy.

ObjectiveTo estimate the prevalence of overweight/obesity at 12 months in an Italian birth cohort and to identify factors related to an increased likelihood of being overweight. MethodsThe Italian NASCITA birth cohort was analysed. Infants were classified as underweight (<5th), normal weight (5th-85th), and overweight (>85th centile) at 12 months of age according to the World Health Organization percentiles of body mass index and the prevalence of overweight/obesity was estimated. To test the association between the chance of being overweight/obese and parental and newborn characteristics, and infant feeding, healthy newborns (no preterm/low birth weight, and with no malformations), with appropriate-for-gestational-age birth weight were selected, and univariate and multivariate analyses were performed ResultsThe prevalence of overweight was 23.5% (95%CI 22.2-24.8) in the 4,270 neonates followed during their first year of life, and 23.7% (631/2749) in healthy newborns with a birth weight that was appropriate for gestational age. A big infant appetite (Odds Ratio 4.39, 95%CI: 2.73-7.07), living in southern Italy (OR 1.64, 95%CI: 1.35-2.00) and maternal age <30 years (OR 1.39, 95%CI: 1.05-1.83) were the main variables associated with a greater likelihood of being overweight/obese. Exclusive breastfeeding for at least 6 months did not influence the chance of being overweight. ConclusionsThe sociodemographic factors (e.g. area of residence, age) seem to be the most relevant determinants influencing the chance of being overweight. In order to prevent childhood and adult obesity, early interventions should be set up or improved, with particular attention to vulnerable families.