Randomised controlled trial of a theory-based behavioural intervention to reduce formula milk intake

Objective: To assess the efficacy of a theory-based behavioural intervention to prevent rapidweight gain in formula-milk fed infants. Design: In this single (assessor) blind, randomised controlled trial, 669 healthy full-terminfants receiving formula-milk within 14 weeks of birth were individually-randomised tointervention (n=340) or attention-matched control (n=329) groups. The intervention aimed toreduce formula-milk intakes, and promote responsive feeding and growth monitoring toprevent rapid weight gain (>+ 0.67 standard deviation scores [SDS]). It was delivered tomothers by trained facilitators up to infant age 6 months through 3 face-to-face contacts, 2telephone contacts, and written materials. Results: Retention was 93% (622) at 6 months, 88% (586) at 12 months, and 94% attended >4/5 sessions. The intervention strengthened maternal attitudes to following infant feedingrecommendations, reduced reported milk intakes at ages 3 (-14%; intervention vs controlinfants), 4 (-12%), 5 (-9%), and 6 (-7%) months, slowed initial infant weight gain frombaseline to 6 months (mean change 0.32 vs 0.42 SDS, baseline-adjusted difference(intervention vs control) -0.08 [95% CI; -0.17, -0.004] SDS), but had no effect on the primaryoutcome of weight gain to 12 months (baseline-adjusted difference -0.04 [-0.17, 0.10] SDS).By 12 months, 40.3% of infants in the intervention group and 45.9% in the control groupshowed rapid weight gain (OR: 0.84 [95% CI; 0.59, 1.17]). Conclusions: Despite reducing milk intakes and initial weight gain, the intervention did notalter the high prevalence of rapid weight gain to age 12 months suggesting the need forsustained intervention.