Exploring Relationships Between Clinic Intervention Dosage and Child Weight Trajectories in the Greenlight Plus Trial

To examine the relationship between dosage of the clinic component and child weight status in the Greenlight Plus Trial, a clinic plus digital intervention aimed to reduce early childhood obesity.

Longitudinal data were used from parent-child dyads (N=900) in the Greenlight Plus Trial. Clinic intervention dosage was assessed after each well child visit (WCV), as the sum of parent-reported receipt of: (1) a Greenlight booklet; (2) discussion of booklet content; and/or (3) goal setting. Multivariable models assessed the relationship between dosage and child weight-for-length (WFL).

Across all WCVs (n=7200), parents reported not receiving any clinic intervention component at 20% of visits, receiving booklet only (dosage score=1) at 39.2% of visits, booklet receipt and discussion (dosage score=2) at 11.7% of visits, and booklet receipt, page discussion, and goal setting (dosage score=3) at 26.9% of visits. No association was detected between cumulative dosage and child WFL trajectory (p=0.31). However, we observed a statistically significant difference in the relationship of dosage to WFL in the 2 treatment arms (p=0.021). Within the clinic-only arm, there was a significant association between dosage and child WFL (p=0.005) in the first 6 months.

Exposure to the full conceptual model of behavioral change was limited. Among those who received only the clinic intervention, dosage modestly and transiently improved infant weight. Enhancing primary care behavioral interventions with digital components, such as text messages, between visits may optimize their impact on child health outcomes including healthy growth.