Existing approaches to parent-focused behavioural programs delivered up to 12 months of age which aim to combat childhood obesity are insufficient to improve body mass index (BMI) at approximately two years of age, according to the largest study to date on the topic published in The Lancet.
Globally, around 37 million children under five years live with overweight or obesity [1]. Child obesity has major lifelong health impacts. To prevent obesity, many argue it is crucial to intervene early, before overweight or obesity first develop in early childhood. The WHO recommends a life-long approach to reduce the risk of obesity, starting during pregnancy. It advocates for the provision of guidance on healthy diet, sleep and physical activity in early childhood for parents/caregivers [2].
Therefore, many governments have made early parent-focused programs – such as community parenting classes, home visits or sharing information via SMS/email/app with a focus on building parent's skills and knowledge on topics such as nutrition, physical activity, and sleep - a key strategy for obesity prevention.
However, there has been limited evidence on the effectiveness of such programs, putting policymakers in a challenging position and resulting in decisions to implement potentially resource-intensive programs despite gaps in the evidence.
Lead author Dr Kylie Hunter, University of Sydney (Australia), says, "Obesity is in large part driven by environmental and socio-economic factors that individuals are unable to change. Parents play a vital role, but our study highlights that they cannot be expected to reduce childhood obesity levels alone.
"Broader, coordinated action across society is needed to make healthy choices easier for everyone, regardless of where they live. Alongside support for parents, we need to see coordinated policies which improve affordability of healthy foods, increase access to green spaces, and regulate unhealthy food marketing to tackle childhood obesity."
The authors formed a global collaboration ( TOPCHILD ) of more than 70 researchers across 47 institutions, combining data from 31 trials set across 10 countries. Investigators from all trials worked together and shared their individual participant data resulting in a large dataset of 28,825 participants to examine the impact of obesity prevention programs designed to help parents foster healthy nutrition, sleep and activity patterns in their toddlers. To be included in the meta-analysis, programs needed to commence sometime between pregnancy and 12 months of age and to measure a child weight-related outcome. The authors also disentangled detailed information on the content and delivery of interventions in a complementary piece of research led by Flinders University [3].
Of the 31 trials contributing data, there were 17 trials with individual participant data which assessed BMI at approximately two years of age (a total of 9128 participants). These trialled different intervention approaches [3], including for example:
- A trial in the UK assessing a program where eight weekly sessions were delivered in children centres to groups of eight to ten parents to target behaviours including food provision and movement. [4]
- An Australian trial where women with their first child received eight home visits spread over two years with advice on topics including breastfeeding, timing of introducing solids, screen time and physical activity. [5]
- A trial in the US where primary-care providers set dietary, physical activity or screen time goals with parents, aided by low-literacy booklets, at seven visits from two to 18 months. [6]
With a high level of certainty, the meta-analysis found that the early childhood obesity prevention programs had no effect on BMI of the children at approximately two years old.
Senior author Prof Anna Lene Seidler, University of Rostock (Germany), says, "There are several potential explanations for why current parent-focused programs to prevent obesity in toddlers are not effective. One reason could be that the first year of a child's life can be overwhelming and stressful for parents, leaving them with limited capacity to fully engage in behavioural changes. Once children enter broader social settings such as early childcare and school, programs which create healthier environments for children directly in these setting may be more effective.
"Additionally, the families most affected by childhood obesity – often those in lower socioeconomic groups – are also the least likely to be reached by parent-focused early programs. They often simply do not have the resources or time to attend and adhere to these programs, particularly in the current cost of living crisis. Policy level changes aimed at creating healthier environments for all children are more likely to reach these families."
The authors acknowledge some limitations in their study, including that seven of the 17 trials were rated as high risk of bias due to missing data and/or that data were missing at different rates for participants in the intervention group compared to those in the control group. However, when these studies were excluded from the analysis, the results remained the same.
