Maternal-infant relationship quality and risk of obesity at age 5.5 years in a national US cohort

Background: Poor quality relationships between mothers and toddlers have been associated with higher risk for childhood obesity, but few prospective studies of obesity have assessed maternal-child relationship quality in infancy. In addition it is not known whether the increased risk is associated with the mother's or the child's contribution to the relationship quality. Methods: We analyzed data (n = 5650) from the Early Childhood Longitudinal Study, Birth Cohort, a national study of U. S. children born in 2001 and followed until they entered kindergarten. At 9 months of age, the Nursing Child Assessment Teaching Scale (NCATS) was used to assess the quality of observed playtime interactions between mothers and infants, yielding separate scores for maternal and infant behaviors. Obesity (BMI >= 95th percentile) at age 5.5 years was based on measured weight and height. Results: The prevalence (95% confidence interval) of obesity at 5.5 years of age was higher among children in the lowest quartile of maternal NCATS score (20.2% [95% CI: 17.2%, 23.2%]) than in the highest quartile (13.9% [11.3%, 16.5%]), but maternal NCATS score was not significantly associated with obesity after adjustment for race/ethnicity, maternal education and household income. The prevalence of obesity at 5.5 years of age was similar among children in the lowest quartile of infant NCATS score (17.4% [14.4%, 20.3%]) and in the highest quartile (17.6% 14.4%, 20.8%]), and was not changed with covariate adjustment. Conclusions: Maternal-infant relationship quality, assessed by direct observation at 9 months of age in a national sample, was not associated with an increased risk of obesity at age 5.5 years after controlling for sociodemographic characteristics.