The association of childhood socio-economic position and psychological distress in adulthood: is it mediated by adult socio-economic position?

There is substantial evidence that lower socio-economic position (SEP) is associated with poorer mental health outcomes. However, uncertainties exist about the origins of socioeconomic gradients in mental health problems and the relative contributions of both childhood and adult SEP. In this study we assess the association of childhood SEP with psychological distress in adulthood and investigate how much of this association is mediated by adult SEP. Data for this cross-sectional analysis came from Wave 3 of the Survey of Family, Income and Employment (SoFIE) in New Zealand (n=14,470). Childhood SEP was measured using parental occupation recalled at age 10. Non-specific psychological distress was assessed using the Kessler 10 scale (K10). Adult SEP was measured using five socio-economic indicators (area deprivation, household income, wealth, labour market activity, education). The association of childhood SEP with psychological distress before and after controlling for confounders and adult SEP indicators was determined using logistic regression, with the K10 dichotomised at low/moderate versus high/very high. Sensitivity analyses included birth cohort and sex. There was a weak inverse relationship between increasing proportion of psychological distress with lower childhood SEP. Adjusted for age, sex and ethnicity, respondents with low compared to high childhood SEP had 1.35 greater odds of reporting high psychological distress (95% CI 1.13-1.60). Adjustment for adult mediating SEP variables led to a 77% reduction in the excess odds ratio to 1.08 (95% CI 0.901.29). The relationship did not significantly differ by birth cohort or sex. This finding is consistent with the current evidence that socio-economic circumstances in adulthood are important determinants of inequalities in adult mental health and mediate much of the association of childhood SEP with adult psychological distress.