Early-life determinants of excessive weight gain among low-income children: Examining the adherence of theoretical frameworks to empirical data using structural equation modelling.

BACKGROUND

Although childhood obesity is increasing in low-income regions, theoretical models cannot be adequately applied due to the lack of prospective studies with under 2-year-old children from impoverished populations.

OBJECTIVE

To analyse direct and indirect effects of environmental, maternal, and individual factors on excess weight gain among low-income children during the first year of life.

METHODS

We analysed data from a prospective birth cohort conducted in Brazil, which followed infants at birth, 3rd, 6th, and 12th month of life (n = 205). The weight-for-age z-score was used to calculate the conditional weight gain (CWG). Direct and indirect effects on CWG were estimated using structural equation modelling.

RESULTS

Children's consumption of ultra-processed food (UPF) ≥1 time/day, breastfeeding duration >90 days, and maternal obesity showed a statistically significant direct effect on children's CWG. We observed a positive indirect pathway linking the maternal intake of UPF ≥4 times/day to the CWG, given its direct effect on the infant's UPF consumption.

CONCLUSIONS

In this low-income population, women who were frequent users of UPF tended to introduce these products more frequently into their children's diets. The early trade-off trend in children's diet between breastfeeding and UPF was the leading cause of excessive weight gain.