The Impact of Social Determinants of Health and Lifestyle on the Association of Lipoprotein(a) with Myocardial Infarction and Stroke

Background: In European cohorts, a higher Mediterranean diet or Life's Simple 7 (LS7) score abolished or attenuated the risk associated with increasing Lipoprotein(a) [Lp(a)] on cardiovascular outcomes. This is unstudied in US cohorts. The impact of social determinants of health (SDOH) on the association of Lp(a) with cardiovascular outcomes remains unstudied. We sought to test if a SDOH score and LS7 score impacts the association of Lp(a) with myocardial infarction (MI) or stroke.

Methods: Observational Cohort of US Adults from the Atherosclerosis Risk in Communities (ARIC) and Multi-Ethnic Study of Atherosclerosis (MESA) cohorts. We performed sequential multivariable Cox proportional hazard analysis, first adjusting for age, gender, non-HDL-C, race and ethnicity, then added SDOH and LS7 scores sequentially. The primary outcomes were time until first fatal or nonfatal MI or stroke.

Results: ARIC (n=15,072; median Lp(a)=17.3 mg/dL) had 16.2 years average follow up. MESA (n=6,822; median Lp(a)=18.3 mg/dL had 12.3 years average follow-up. In multivariable analyses adjusted for age, gender, race and ethnicity, and non-HDL-C, Lp(a) was associated (HR, p-value) with MI in ARIC (1.10, <0.001) and MESA (1.09, <0.001), and stroke in ARIC (1.08, <0.001) but not MESA (0.97, 0.50). With SDOH and LS7 added to the model associations remained similar (association of Lp(a) with MI in ARIC 1.09, <0.001 and in MESA 1.10, 0.001, with stroke in ARIC 1.06, <0.003 and in MESA 0.96, 0.39). In models with all covariates, each additional SDOH correlated positively with MI (ARIC 1.13, <0.001; MESA 1.11, <0.001) and stroke (ARIC 1.17, <0.001; HR 1.07, p=0.11) and each additional LS7 score point correlated negatively with MI (ARIC 0.81, <0.001; MESA 0.84, <0.001) and stroke (ARIC 0.82, <0.001; MESA 0.84, <0.001).

Conclusions and relevance: SDOH and lifestyle factors were predictors for MI and stroke that did not impact the association between Lp(a) and cardiovascular events. Our findings support that Lp(a) is an independent risk factor for MI and possibly stroke.