International differences in gradients in early childhood overweight and obesity: the role of maternal employment and formal childcare attendance

Background
There are significant cross-country differences in socio-economic gradients in later childhood and adulthood overweight/obesity; few studies assess whether this cross-national variation is evident from early childhood. Furthermore, the role of childcare in explaining overweight/obesity gradients might vary across countries, given differences in access, quality and heterogeneity within. Additionally, childcare is linked to parental characteristics such as maternal employment. The interplay between childcare and employment in producing early overweight/obesity gradients has received little attention, and might vary cross-nationally.

Methods
Using harmonized data from six high-quality, large datasets, we explore the variation in gradients in early overweight/obesity (at age 3–4 years old) by parental education across several high-income countries (USA, UK, France, the Netherlands, Germany and Japan). We then assess whether differential formal group care use attenuates some of these gradients, and whether this varies across maternal employment.

Results
Gradients in early childhood overweight/obesity by parental education are evident across several developed countries. Countries with higher overall prevalence of early overweight/obesity did not have the largest inequalities across education groups. The contribution of formal group care to producing these gradients varied across countries and across maternal employment status.

Conclusion
Early childhood inequalities in overweight/obesity are pervasive across developed countries, as noted for older children and adults. However, mechanisms producing these gradients vary across national contexts. Our study shows that, given the right context, quality childcare and maternal employment can successfully support healthy weight trajectories and not contribute (or even reduce) social inequalities in early overweight/obesity.