Associations between changes in caregiver's and child's weight status in a community-based obesity intervention programme.

Objectives: We examined whether caregivers of children/adolescents enroled in a randomised controlled trial (RCT) of a family-centred intervention indirectly achieved reductions in body mass index (BMI), and if these were associated with changes in their children's BMI.

Methods: RCT participants were New Zealand children/adolescents aged 4.8-16.8 years with BMI ≥ 98th percentile or >91st with weight-related comorbidities. Participants and accompanying caregivers were assessed at baseline, 12, and 24 months.

Results: Overall, caregivers' BMI was unchanged at 12 or 24 months. Among Māori participants, reductions in caregivers' BMI at 12 months were associated with reductions in their children's BMI SDS at 12 (r = 0.30; p = 0.038) and 24 months (r = 0.39; p = 0.009). Further, children identifying as Māori whose caregivers' BMI decreased at 12 months had greater BMI SDS reductions at 12 months [-0.30 (95% CI -0.49, -0.10); p = 0.004] and 24 months [-0.39 (95% CI -0.61, -0.16); p = 0.001] than children of caregivers with increased/unchanged BMI.

Conclusions: This intervention programme for children/adolescents with obesity did not indirectly reduce caregiver weight status. However, reductions in caregivers' BMI were key to BMI SDS reductions among Māori participants. Given the intergenerational nature of obesity, our findings highlight the importance of culturally relevant, family-focused programmes to achieve clinically meaningful improvements in weight status across the family.