Elsevier

The Lancet

Volume 360, Issue 9346, 23 November 2002, Pages 1640-1645
The Lancet

Articles
Association between children's experience of socioeconomic disadvantage and adult health: a life-course study

https://doi.org/10.1016/S0140-6736(02)11602-3Get rights and content

Summary

Background

Research into social inequalities in health has tended to focus on low socioeconomic status in adulthood. We aimed to test the hypothesis that children's experience of socioeconomic disadvantage is associated with a wide range of health risk factors and outcomes in adult life.

Methods

We studied an unselected cohort of 1000 children (born in New Zealand during 1972–73) who had been assessed at birth and ages 3, 5, 7, 9, 11, 13, and 15 years. At age 26 years, we assessed these individuals for health outcomes including body-mass index, waist: hip ratio, blood pressure, cardiorespiratory fitness, dental caries, plaque scores, gingival bleeding, periodontal disease, major depression, and tobacco and alcohol dependence, and tested for associations between these variables and childhood and adult socioeconomic status.

Findings

Compared with those from high socioeconomic status backgrounds, children who grew up in low socioeconomic status families had poorer cardiovascular health. Significant differences were also found on all dental health measures, with a threefold increase in adult periodontal disease (31·1% vs 11·9%) and caries level (32·2% vs 9·9%) in low versus high childhood socioeconomic status groups. Substance abuse resulting in clinical dependence was related in a similar way to childhood socioeconomic status (eg, 21·5% vs 12·1% for adult alcohol dependence). The longitudinal associations could not be attributed to life-course continuity of low socioeconomic status, and upward mobility did not mitigate or reverse the adverse effects of low childhood socioeconomic status on adult health.

Interpretation

Protecting children against the effects of socioeconomic adversity could reduce the burden of disease experienced by adults. These findings provide strong impetus for policy makers, practitioners, and researchers to direct energy and resources towards childhood as a way of improving population health.

Introduction

Research into social inequalities and health has tended to focus on low socioeconomic status in adulthood as the main causal variable, cardiovascular disease as the main outcome variable, adults' stress experiences as the main mediating mechanism, and redistribution of income among adult workers as the solution.1, 2 Previous research documenting significant but modest correlations between measures of low childhood socioeconomic status and adult health3, 4, 5, 6 has been interpreted as suggesting that the experience of disadvantage during childhood could have small—albeit long-lasting and harmful—effects on adult health. However, several gaps in the evidence base challenge this interpretation.

First, because measurement of childhood socioeconomic status has not been ideal, previous research might have actually underestimated the long-term effect of childhood experiences. Most studies rely on adults' retrospective reports about their childhood circumstances,7, 8, 9 but there is evidence that such reports are compromised by poor recall and measurement error.10 Additionally, most studies measure childhood circumstances by using retrospective reports about a single age (eg, when the child was 14 years old) or about short durations during childhood. Limited-duration information is an unreliable indicator of, and weak proxy for, more complete information spanning the entire childhood period.11 We aimed to use prospective, repeated measures of socioeconomic status to quantify the degree of socioeconomic disadvantage experienced throughout childhood to examine its relation to adult health.

Second, to ascertain whether children's experience of disadvantage with respect to socioeconomic status is related to their adult health, the child's initial infant health status should be controlled for. Children from families of low socioeconomic status are more likely to begin life in poor health because fetal and birth complications are more prevalent in the lower socioeconomic strata.12, 13 Poor newborn health is known to have continuity to adult health.14 In this study, we aimed to control for perinatal health before assessing the association between childhood socioeconomic status and adult health.

Third, to ascertain whether the experience of disadvantage with respect to socioeconomic status during childhood is related to adult health, adult socioeconomic status also needs to be controlled for, since there is moderate continuity of socioeconomic status across the life course.15 A statistical association between childhood socioeconomic status and adult health could therefore be mistaken as evidence for a childhood effect, whereas it might simply represent concurrent effects of adult socioeconomic status on adult health.16, 17 We planned to examine the influence of life-course continuity in socioeconomic status, before assessing the effects of childhood socioeconomic status on adult health.

Fourth, if there is an association between childhood socioeconomic status and adult health, it is important to test whether changes in socioeconomic circumstances after childhood can counteract the effects of childhood socioeconomic status. According to the upward mobility hypothesis, a rise in socioeconomic status from childhood to adulthood could have a protective effect and lead to better health. The downward mobility hypothesis predicts that a fall in the socioeconomic status hierarchy could have a risk effect and lead to worse health. By contrast, according to the social-origins hypothesis, growing up in conditions of low socioeconomic status has enduring adverse influences on adult health, irrespective of adult socioeconomic status. We aimed to test these three life-course hypotheses in this study.

Finally, it is important to establish whether the association between childhood socioeconomic status and adult health is pervasive across health domains or is domain specific. Knowledge about the pervasiveness versus specificity of these longitudinal associations can help to focus attention on plausible risk mechanisms. We intended to examine the association between low childhood socioeconomic status and a wide range of adult health outcomes-including physical health, dental health, and mental health and substance abuse—that are known to impair life functioning and that signal risk for future disease.

Section snippets

Sample

Participants were members of the Dunedin Multidisciplinary Health and Development Study—a longitudinal investigation of health and behaviour in a complete birth cohort.18 The study members were born in Dunedin, New Zealand, between April, 1972, and March, 1973. Of these individuals, 1037 (91% of eligible births; 52% male) participated in the first follow-up assessment at age 3 years, which constituted the base sample for the remainder of the study. Cohort families represented the full range of

Results

All physical health measures at age 26 years, except systolic blood pressure, showed a graded relation with childhood socioeconomic status (table). As socioeconomic status increased, body-mass index and waist:hip ratio decreased and cardiorespiratory fitness increased. The adverse associations with low childhood socioeconomic status remained significant after controlling for infant health, and after adding statistical controls for contemporaneous adult socioeconomic status.

All dental health

Discussion

This life-course study, spanning the period from birth to age 26 years, shows that low childhood socioeconomic circumstances have long-lasting negative influences on adult health, irrespective of what health cache one begins life with, or where one ends up in the socioeconomic hierarchy as an adult. Specifically, the findings document that the social gradient in health—which has been amply documented among middle-aged and older adults—actually emerges in childhood. Whereas clinical and research

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