Parental Income Gradients in Adult Health: A National Cohort Study

ABSTRACT 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. WHAT IS KNOWN It is well documented that higher incomes among adults is positively associated with health and longevity, however, less is known about how childhood parental income is related to adult health. WHAT THIS STUDY ADDS We used administrative data on seven full Norwegian birth cohorts with information on parental income covering the whole childhood and a broad set of adult health measures taken from primary and secondary health service consultations. We demonstrate substantial associations between childhood parental income and overall measures of adult health, as well as for a large number of specific diagnoses, within a societal context where access to high-quality health care is universal. These gradients in adult health by childhood parental income did not vary substantively by other childhood circumstances, such as health at birth, mother’s marital status, and parental education. Despite individuals’ own completed education and adult income being strongly related to adult health, we found remaining adult health gradients by childhood parental income within all subpopulations stratified by own level of adult socioeconomic attainment.