Background/objectives: This study analysed the relationship between early childhood socioeconomic status (SES) measured by maternal education and household income and the subsequent development of childhood overweight and obesity. Subjects/methods: Data from seven population-representative prospective child cohorts in six high-income countries: United Kingdom, Australia, the Netherlands, Canada (one national cohort and one from the province of Quebec), USA, Sweden. Children were included at birth or within the first 2 years of life. Pooled estimates relate to a total of N = 26,565 included children. Overweight and obesity were defined using International Obesity Task Force (IOTF) cut-offs and measured in late childhood (8–11 years). Risk ratios (RRs) and pooled risk estimates were adjusted for potential confounders (maternal age, ethnicity, child sex). Slope Indexes of Inequality (SII) were estimated to quantify absolute inequality for maternal education and household income. Results: Prevalence ranged from 15.0% overweight and 2.4% obese in the Swedish cohort to 37.6% overweight and 15.8% obese in the US cohort. Overall, across cohorts, social gradients were observed for risk of obesity for both low maternal education (pooled RR: 2.99, 95% CI: 2.07, 4.31) and low household income (pooled RR: 2.69, 95% CI: 1.68, 4.30); between-cohort heterogeneity ranged from negligible to moderate (p: 0.300 to < 0.001). The association between RRs of obesity by income was lowest in Sweden than in other cohorts. Conclusions: There was a social gradient by maternal education on the risk of childhood obesity in all included cohorts. The SES associations measured by income were more heterogeneous and differed between Sweden versus the other national cohorts; these findings may be attributable to policy differences, including preschool policies, maternity leave, a ban on advertising to children, and universal free school meals.
Bibliographical noteFunding Information:
EPOCH was partly supported by Canadian Institutes of Health Research (J. McGrath OCO-79897, MOP-89886, MSH- 95353; L. Séguin ROG-110537). For information on funding of individual cohort please see supplementary information. Additional collaborators of the EPOCH (Elucidating Pathways of Child Health inequalities) Collaborative Group include: (alphabetically) Clare Blackburn (University of Warwick, UK), Sven Bremberg (Karolinska Institutet, Sweden), Anders Hjern (Center for Health Equity Studies & Karolinska Institutet, Sweden), Jody Heymann (UCLA, USA), Lisa Kakinami (Concordia University, Canada), Lynn Kemp (Western Sydney University, Australia), Lucie Laflamme (Karolinska Institutet, Sweden), Johan Mackenbach (Erasmus MC, The Netherlands), Richard Massé (Ministère de la santé et des services sociaux, Gouvernement du Québec, Canada), Marie-France Raynault (Center Hospitalier de l’Université de Montréal-CHUM, Quebec), Paul Wise (Stanford University, USA). Open access funding provided by Linköping University.
Publisher Copyright: © 2022, The Author(s).