Prospective associations between social vulnerabilities and children's weight status. Results from the IDEFICS study

Background/objectives In high-income countries, childhood obesity follows a clear socioeconomic gradient with greater prevalence in children with lower socioeconomic status (SES). The extent to which the trend of other social vulnerabilities over time and the accumulation of these vulnerabilities can affect children's weight is still unknown. Subjects/methods In the IDEFICS study, 8624 children aged 2.0-9.9 years from eight European countries were examined at baseline and after 2 years. Sociodemographic variables, maternal body mass index (BMI), and lifestyle were reported by parents. Children were measured and classified as thin, normal weight, and overweight/obese using the extended IOTF criteria. Four vulnerable groups were defined: children whose parents were migrants, children whose parents lack a social network, children from non-traditional families (children not living with both biological parents), and children with unemployed parents. Logistic mixed-effects models were used to study the association between vulnerabilities and children's weight at baseline and follow-up, temporal trends in vulnerabilities and children's weight and accumulation of vulnerabilities and children's weight. Models were adjusted for lifestyle, maternal BMI, parental education, and income. Results Children whose parents lost their social support at follow-up were more likely to be thin than non-vulnerable children (OR = 1.69, 99% CI = 1.03-2.78). Children whose parents had a migrant background (OR = 1.30, 99% CI 1.04-1.62), children from non-traditional families at both time points (OR = 1.40, 99% CI 1.03-1.90) and whose parents were unemployed at baseline and follow-up (OR = 2.03, 99% CI 1.03-3.99) were more likely to be overweight/obese compared to non-vulnerable children. Cross-sectionally, we did not find an association between parental lack of network, non-traditional family structure, or employment and children's weight status. Conclusions Policy actions are required to tackle inadequate weight loss and gain among vulnerable children (especially those exposed over the long term) since they are at a higher risk of thinness and overweight.