Race and Ethnic-Specific Burden of Aortic Valve Calcium and Its Association With Long-Term Aortic Stenosis: Multi-Ethnic Study of Atherosclerosis

Background: Racial and ethnic differences have been reported for aortic valve calcium (AVC) and long-term aortic stenosis (AS). Whether these differences are due to differing risk factor profiles or the burden of AVC is unknown. Methods: Baseline AVC was quantified using the Agatston method among 6812 MESA (Multi-Ethnic Study of Atherosclerosis) participants. AVC scores were not reported to participants. The primary outcome of long-term moderate or severe AS was adjudicated using standard clinical criteria. We calculated multivariable Cox proportional hazards with log-transformed AVC as a continuous variable for each race and ethnicity. Results: The mean age was 62 years, and 47% of participants were women. Over a median follow-up of 16.7 years, 140 participants were diagnosed with moderate (n=56) and severe AS (n=84). The prevalence of baseline AVC >0 by self-reported race and ethnicity was White (15.8%), Hispanic (13.3%), Black (12.3%), and Chinese (8.3%). The rate of long-term incident moderate-severe AS was highest for White participants (2.1/1000 person-years) and lowest for Chinese participants (0.5/1000 person-years). The association of AVC with moderate-severe AS was significant for all race and ethnicity groups: White hazard ratio, 1.82 (95% CI, 1.62–2.03); Hispanic hazard ratio, 2.18 (95% CI, 1.82–2.62); Black hazard ratio, 2.28 (95% CI, 1.78–2.93); and Chinese hazard ratio, 3.65 (95% CI, 1.05–12.71) per 1 unit higher log transformed AVC. There was no interaction by race and ethnicity ( P =0.26) when modeling Black versus non-Black participants. Conclusions: The racial and ethnic groups with a higher baseline prevalence of AVC had a higher long-term incidence of moderate-severe AS, but a similar relative association between AVC and moderate-severe AS regardless of baseline atherosclerotic cardiovascular disease risk. Our findings suggest that differences in AS by race and ethnicity may likely be explained by the burden of AVC.