|Contribution title||Relationship between socioeconomic status and weight gain during infancy|
|Form of presentation||Poster|
Background: Rapid weight gain during infancy is a strong risk factor for obesity and related diseases in later life. It has been suggested that children from lower socioeconomic status (SES) families have a higher prevalence of obesity than those from higher SES families. Very few studies have focused on examining the association between SES and rapid weight gain during infancy.
Objective: The aim of the present study was to investigate the association between social economic status (SES) and weight gain in different time periods during infancy (0-6, and 6-11 months), identify the prenatal factors and infant feeding factors mediating the association between SES and infant weight gain in these different age windows.
Method: We used longitudinal growth data of children participating the BEEBOFT study, which is a population-based cluster randomized control intervention trail for the primary prevention of overweight among young children. Weight gain was calculated by subtracting the weight for age Z score between two time points. Family SES was indexed by maternal education level. Path analysis was performed to assess the mediating pathways between SES and infant weight gain.
Result: Overall, in the period of infant age 0-6 months, infants with low- and middle- educated mothers had increased weight (z-score) gain for (β=0.38; 95% CI: 0.21–0.55, and β=0.13; 95 % CI: 0.01–0.24) compared to infants with high-educated mothers (P<0.01). In the period of infant age 6-11 months, there was no educational difference in infants’ weight gain. The association between maternal education level and increased infant weight gain in the period of 0-6 months was mediated by prenatal factors including infant birth weight, gestational age at child birth, and infant feeding factors including duration of breastfeeding, and timing of introduction of complementary food. After adjusting for these mediators, there was no association between maternal education level and infant weight gain in the period of 0-6 months (β=-0.05, p=0.67).
Conclusion: Children with low-educated mothers had an increased weight gain during the first 6 months of life. The observed association between maternal education level and infant weight gain could be explained by prenatal factors including infant birth weight, gestational age at child birth, and infant feeding factors including duration of breastfeeding, and timing of introduction of complementary food.