Journal Article

Health outcomes of only children across the life course: an investigation using Swedish register data​

Keenan, K., Barclay, K. J., Goisis, A.
Population Studies, 77:1, 71–90 (2023)
Open Access


​Only children – children with no full biological siblings – are a growing subgroup in many high-income settings, but we know little about their life course health outcomes. We address this research gap using Swedish population register data for cohorts born 1940-1975 and introducing conceptual and methodological innovations to the literature. We compare the health of only children with children from multi-child sibling groups, taking into account birth order, family size and the presence of half-siblings. Only children had lower height and fitness scores, were more likely to be overweight or obese in late adolescence, and had higher mortality, than those with 1 or 2 siblings. However, only children without half-siblings were always healthier than those with half-siblings, suggesting that parental disruption confers additional disadvantages. The health disadvantage was attenuated but not fully explained by adjustment for parental characteristics and after employing within-family maternal cousin comparison designs.

Keywords: Sweden, adult mortality, family size, health, only child
The Max Planck Institute for Demographic Research (MPIDR) in Rostock is one of the leading demographic research centers in the world. It's part of the Max Planck Society, the internationally renowned German research society.