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 (SE) BMI than controls (16.59 [0.18] vs 16.95 [0.18]; absolute difference, -0.36; P = .049). Sex moderated this effect; female participants in the responsive parenting group had a lower mean (SE) BMI than female participants in the control group (16.31 [0.23] vs 17.24 [0.22]; absolute difference, -0.93; P = .002), 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.