Association of apolipoprotein B and apolipoprotein A1 levels with social determinants of health and coronary artery disease mortality in the United Kingdom Biobank - is there a need for consideration?

Background: A higher prevalence of cardiovascular risk factors has previously been shown to be associated with adverse social determinants of health (SDoH) and to explain some of their impact on cardiovascular risk. Whether there is a relationship between lipid parameters, specifically apolipoprotein B (apoB), apolipoprotein A1 (apoA1), their ratio (apoB/apoA1), and SDoH, and whether coronary artery disease (CAD) mortality risk associated with circulating apoB and apoA1 is modified by SDoH was unclear.

Methods: We investigated associations of apoA1, apoB, and apoB/apoA1 with the level of education and household income and their joint impact on CAD mortality in participants of the UK Biobank (UKB) with and without prevalent CAD at enrollment. Hazard ratios for CAD mortality were estimated after adjusting for SDoH and clinical covariates.

Results: In 292 804 participants without established CAD, apoB, and the apoB/apoA1 ratio were inversely associated with level of education and household income, whereas apoA1 was positively associated with household income. Adjustment for education level and household income coupled with the number of people living in the household did not attenuate the association between the apolipoprotein levels and incident CAD mortality rates. In a cohort of 13 826 participants with prevalent CAD, apoA1 levels were inversely associated with level of education. Higher apoB levels were only associated with greater CAD mortality risk after adjustment for risk factors. Risk estimation for CAD death through circulating apoA1 levels requires accounting for significant differences by sex.

Conclusion: Circulating lipid parameters are associated with SDoH in individuals without CAD. CAD mortality risk estimation through apoA1 and apoB levels does not require accounting for SDoH.