Socioeconomic Health Inequalities: Differences Between and Within Individuals

Research on socioeconomic health inequalities has primarily relied on univariate markers of socioeconomic status (SES), measured at one point in time. Using data from the UKHLS dataset (2009{2020), we build an age-conditional multidimensional SES index for the adult population in the UK. By using a "within-between" model we disentangle the relationship between health outcomes and: i) between-individual differences in SES, and ii) within-individual variations of SES across time. Results show that both are positive and highly significant predictors of physical and mental health. However, we find that these relationships are not linear and that within and between effects interact. While higher levels of SES are always associated with an increase in physical health, for mental health, after some point (SES = 0.613), higher average SES is associated with a score decrease. For an individual with the lowest average SES rank we observe a large and significant effect of a within-individual increase in SES on mental health (8.91) and physical health (1.82), however, this within-effect diminishes for those individuals with higher average SES. Individuals with high expected mobility are also found to have significantly better health scores, particularly for mental health.