Distal and variably proximal causes: Education, obesity, and health

Medical sociologists hold that social conditions generate disparities across a host of health conditions through exposure to a variety of more proximate risk factors. Though distal and proximal causes jointly influence disease, the nature of risk accumulation may differ appreciably by the link of a proximal cause to the outcome in question. This paper employs a representative sample of over 3000 American older adults to examine whether position in the educational gradient amplifies the effect of obesity on two health outcomes. Results indicate that educational inequalities amplify the effect of high body mass index on disability (unstandardized coefficients across education groups range from −.05 [ns] to .26 [p < .01] among overweight respondents yet reach .17 [ns] to .73 [p < .001] among severely obese adults), but fail to amplify the consequences of severe obesity in the case of C-reactive protein (CRP) levels. Instead, educational gradients in CRP are most pronounced at lower levels of body mass. Sex-specific analyses further clarify these patterns, as the connections between CRP and body mass are particularly strong among women. We conclude that risk accumulation processes differ based on the proximity of causes to the health outcome under examination.

► From this sample of older Americans, levels of C-reactive protein and disability are generally higher among those who have lower levels of education.
► Disparities in education amplify the effect of high body mass index on disability.
► The relationship between C-reactive protein and body mass index is twice as strong for women than for men, and it is not moderated by educational attainment.
► When causes are relatively proximate to a health outcome, there is less room for problems associated with low education to compound already-existent proximate risks.