The prevalence of overweight among 4-year-olds during and after the COVID-19 pandemic was associated with socioeconomic burden.

Aim: To assess the prevalence of overweight among Swedish 4 year olds in 2018, 2020 and 2022, taking socioeconomic variables into account.

Methods: Aggregated regional data on children's body mass index were collected. The socioeconomic Care Need Index (CNI), foreign background, low education, being a single parent, low income and childhood poverty, were assessed. The differences in overweight, including obesity, were tested for Sweden and for regions.

Results: Data were available for 303 843 children, representing 87% of children born in 2014, 2016 and 2018. Overweight or obesity were found in 11 177 (11.4%) of children in 2022, decreasing from 2020 (13.3%, p < 0.001) but at the same level as in 2018. Regional low CNI, low level of foreign background, education and income as well as being a single parent were associated with a higher prevalence of overweight or obesity in all cohorts (p < 0.001). In regions with high levels of childhood poverty, overweight or obesity were more prevalent during (p = 0.009) and after the pandemic (p < 0.001).

Conclusion: Three national cohorts demonstrate that the increase in overweight during the COVID-19 pandemic has returned to pre-pandemic levels, but the inequalities in health associated with socioeconomic vulnerability of the regions remained.