Parental Income Gradients in Adult Health: A National Cohort Study

INTRODUCTION. Disparities in health by adult income are well documented, but we know less about the childhood origins of health inequalities. This study examined the association between parental income in childhood and health in adulthood. METHODS. We used administrative data on seven complete Norwegian birth cohorts born 1967-1973 (N = 429, 886) to estimate the association between parental income from birth to age 18, obtained from tax records available from 1967, linked with administrative registries on health. Health measures, observed between ages 39 to 43, were taken from registry data on consultations at primary health care services and hospitalizations and out-patient specialist consultations registered in the National Patient Registry. RESULTS. Low parental income during childhood was associated with a 10, 2 percentage-point higher risk of overall disorders between the 5% highest (66.8%, CI 66.2-67.3) and lowest (77.2%, CI 76.6-77.8) parental income vigintiles. Absolute differences were largest for disorders related to musculoskeletal pain, injuries, and depression (7-9 percentage-point difference). There were also differences for hypertension (8%, CI 7.9-8.5 versus 4%, CI 4.1-4.7) and diabetes (3.2%, CI 3.0-3.4 versus 1.4%, CI 1.2-1.6), but smaller differences in consultations related to respiratory disorders (20.9% CI 20.4-21.5 versus 19.7% CI 19.2- 20.3). Stratified analyses by other parental characteristics (education and marital status) and own adult characteristics (education and income) still showed a parental income gradient. CONCLUSIONS. Low parental income in childhood was typically associated with a two-to-threefold increase in somatic and psychological disorders measured in adulthood, even in a setting with universal health care. This indicates that access alone is not enough to break intergenerational patterns of socioeconomic differences in health.