A prevailing hypothesis about the association between income inequality and poor health is that inequality intensifies social hierarchies, increases stress, erodes social and material resources that support health, and subsequently harms health. However, the evidence in support of this hypothesis is limited by cross-sectional, ecological studies and a scarcity of developmental studies. To address this limitation, we used pooled, multilevel data from the Health Behaviour in School-aged Children study to examine lagged, cumulative, and trajectory associations between early-life income inequality and adolescent health and well-being. Psychosomatic symptoms and life satisfaction were assessed in surveys of 11- to 15-year-olds in 40 countries between 1994 and 2014. We linked these data to national Gini indices of income inequality for every life year from 1979 to 2014. The results showed that exposure to income inequality from 0 to 4 years uniquely predicted psychosomatic symptoms and lower life satisfaction after controlling lifetime mean income inequality, national per capita income, family affluence, age, and cohort and period effects. Income inequality from 5 to 9 years also related to symptoms and low life satisfaction in females. The cumulative income inequality exposure in infancy and childhood (i.e., average Gini index from birth to age 10) related to more symptoms and lower life satisfaction in adolescence. Finally, individual trajectories in early-life inequality (i.e., linear slopes in Gini indices from birth to 10 years) related to fewer symptoms and higher life satisfaction, indicating that earlier exposures mattered more to predicting adolescent health and wellbeing. These results help to establish the antecedent-consequence conditions in the association between income inequality and health and suggest that both the magnitude and timing of income inequality in early life have developmental consequences that manifest in reduced health and well-being in adolescence.
- Income inequality
- Health Behaviour in School-aged Children