Long-Term Effects of a Responsive Parenting Intervention on Child Weight Outcomes Through Age 9 Years

Importance Behavioral interventions to treat childhood obesity have had limited success. Primary prevention is desirable, but whether intervention effectiveness can be sustained is unknown. Objective To examine the effect of an intervention designed for the primary prevention of obesity and delivered through age 2 years on weight outcomes through age 9 years. Design, Setting, and Participants A longitudinal observation of a single-center randomized clinical trial comparing a responsive parenting intervention vs a home safety intervention (control) among primiparous mother-child dyads who completed the assessment at age 3 years with follow-up to age 9 years. All data were analyzed from January 21 to November 15, 2024. Interventions Research nurses conducted 4 home visits during infancy and research center visits at ages 1 and 2 years totaling less than 10 contact hours. The responsive parenting curriculum focused on feeding, sleep, interactive play, and emotion regulation. Main Outcomes and Measures The primary outcome is body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) across 4 assessments from age 3 through 9 years, with the assessment of study group differences using repeated-measures analysis. A test for an interaction between sex and study group was planned. Secondary outcomes include BMI z scores and prevalence of overweight (BMI ≥85th to <95th percentile) and obesity (BMI ≥95th percentile) at 5, 6, and 9 years. Results Of the 232 primiparous mother-child dyads (116 per group) (7 Asian [3%], 11 Black [5%], 1 Native Hawaiian or Other Pacific Islander [0.4%], 207 White [89%], and 6 children with other race and ethnicity [including Asian, Indian, Hispanic, Dominican, and other race; 2.5%]; 121 male children [52%]), 177 (76%) had anthropometric data at age 9 years. From ages 3 to 9 years, children in the responsive parenting group had a lower mean (SD) BMI than controls (16.64 [0.21] vs 17.07 [0.20]; absolute difference, −0.43; P = .049). Sex moderated this effect; female participants in the responsive parenting group had a lower mean (SD) BMI than female participants in the control group (16.32 [0.26] vs 17.32 [0.26]; absolute difference, −1.00; P = .007), with no group differences among male participants. Cross-sectional analyses revealed no differences in BMI z scores or prevalence of overweight or obesity at ages 5, 6, and 9 years between the responsive parenting group and the control group. Conclusions and Relevance An early-life responsive parenting intervention resulted in lower BMI from age 3 to 9 years compared with a control intervention. This group difference was driven by effects on female participants, with differences appearing to dissipate over time. A life-course approach may be required to sustain the benefits of early-life responsive parenting interventions for obesity prevention. Trial Registration ClinicalTrials.gov Identifier: NCT03555331