The mediating effects of home environment on the relationship between maternal BMI and childhood obesity: Findings from the ECHO-wide cohort.

UNLABELLED: Maternal pre-pregnancy obesity could affect long-term excessive child weight gain. Positive home environments, encompassing supportive social settings within a household, may mitigate such effects by promoting engagement in healthier behaviours. However, the mediating role of home environments is not established. The study examined whether nurturing and stimulating home environments mediate the association between maternal pre-pregnancy body mass index (BMI) and BMI z-score in early childhood (3-6 years of age). A retrospective cohort study of mother-child pairs using data from the Environmental Influences on Child Health Outcomes (ECHO) program in the USA was conducted, with data collected between September 2016 and March 2023 in children born between 2002 and 2011. The home environment was assessed using the Infant-Toddler Home Observation for Measurement of Environment (IT-HOME) questionnaire, with the Parental Responsivity, Acceptance, Learning Materials, Organisation, Variety and Parental Involvement subscales. Structural equation modelling (SEM) was used to test the potential mediating effects of IT-HOME subscales. The final analytic sample comprised 1341 mother-child pairs. Children whose mothers were overweight and obese during pre-pregnancy had significantly higher BMI z-scores in early childhood as compared to those of mothers who had normal weight, across models examining the six IT-HOME subscales as well as the total IT-HOME z-score. The home environment did not mediate the association between maternal pre-pregnancy BMI and early childhood BMI z-score. CONCLUSION: This study had insufficient evidence to show that the home environment acted as a mediator in reducing the childhood BMI z-score associated with maternal pre-pregnancy BMI. Other dimensions, such as quality diet and physical activity stimulation, should be further explored as potential mediators in future studies. WHAT IS KNOWN: • To the best of our knowledge, this is the first study to look at the mediation effect of home environment in the relationship between childhood obesity and maternal pre-pregnancy BMI in 3-6-year-olds in the USA population. WHAT IS NEW: • There was no evidence that a supportive and enriched home environment during infancy and toddlerhood acted as a mediator in attenuating the otherwise positive relationship between childhood obesity and maternal pre-pregnancy BMI in the USA population. • Future research should explore the mediating effects of dietary quality, physical activity dimensions, and the dynamics of age-specific effects of the home environment on weight trajectories across infancy, early childhood, middle childhood, and adolescence to have targeted interventions that are protective against childhood obesity.