Spillover effects of childhood obesity prevention interventions

Key messages

  • Childhood obesity prevention initiatives are complex interventions that aim to improve children’s obesity-related behaviors and provide health promoting environments.
  • These interventions often impact individuals, communities, and outcomes not primarily targeted by the intervention or policy (“spillover effects”).
  • Spillover effects of childhood obesity prevention interventions may occur at the individual level (such as among parents, caregivers, family members of intervention participants, school teachers, and community leaders) or at the wider community or settings level (e.g., in communities or settings not directly exposed to an intervention)
  • Limited evidence indicates that positive spillover effects of childhood obesity prevention interventions can be observed in parents/caregivers and families of targeted participants.

Project lead(s)

Dr Vicki Brown, Deakin Health Economics, Institute for Health Transformation, Deakin University, Melbourne Australia

What is the problem?

Child obesity prevention interventions may create “spillover” effects for conditions other than obesity and for populations not directly targeted by the intervention.  Limited evidence currently exists on these spillover effects, and no published systematic review of the evidence for spillovers exists.

What did we do?

We published a systematic review that synthesised the evidence for spillover effects of childhood obesity prevention interventions.

What did we find?

Twenty studies reporting 15 interventions were included from the academic literature and 41 unique randomised controlled trial records from the search of trial registries were included.

The most commonly reported positive spillover was for diet or nutrition-related outcomes among siblings and parents of children involved in obesity prevention intervention.

Three studies reported statistically significant effects on BMI (one study reporting BMI effect in parents; two studies reporting BMI effect in children not exposed to the intervention).

Limited evidence exists for spillover effects for physical activity, sleep or other outcomes.

Why does it matter?

  • The nature and magnitude of spillover effects from childhood obesity prevention interventions are generally unmeasured, unknown, and therefore unaccounted for when evaluating the overall benefits and costs of these types of interventions.
  • We have shown, from the limited data available, that spillover effects can represent positive benefits for parents or caregivers, families, and communities.
  • Greater attention to spillover effects in childhood obesity prevention trials and interventions will build a stronger case for obesity prevention in the future.


Spillover effects of childhood obesity prevention interventions: A systematic review – Brown – Obesity Reviews – Wiley Online Library

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