The health of children and adolescents in high income countries negatively relates to income inequality. Theoretical interpretations of this association suggest that inequality intensifies social hierarchies, erodes social or material resources that support health or impacts socio-emotional development in childhood and subsequently harms health. The evidence in support of this causal interpretation is limited by a reliance on cross-sectional, ecological studies. Using multilevel panel data from the Health Behaviour in School-aged Children (HBSC) study, this paper examines lagged and contemporaneous associations between national income inequality and health and well-being during adolescence. Health symptoms and life satisfaction were measured in successive surveys of 11- to 15-year-olds in Europe and North America between 1994 and 2014. These data were linked to country-level income inequality for each survey year (contemporaneous effects) and for earlier developmental periods, at 0-4 years and 5-9 years (lagged effects), dating back to 1979 – the birth year of 15-year-olds in the 1994 survey cycle. Societal growth curve modelling was used to pool data from successive survey cycles and to isolate age, period, and cohort effects.
The results show evidence of lagged effects of income inequality during childhood (5-9 years) on health symptoms and life satisfaction in adolescents (11-15 years), after differences in concurrent income inequality and income per capita, cohort, time period, and individual gender, age, and affluence were held constant. This period of development for income inequality exposure coincides with the early school years when social relationships extend from the family to school and community settings. Inequality may shape child developmental trajectories in ways that later manifest in reduced health and well-being. Though not causal evidence in the strictest sense, these findings establish antecedent-consequence conditions in the association between income inequality and health. The practical and theoretical implications of these results are discussed.