Role of coronary artery calcium in the association between hormone therapy status and incident death and cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVE: To investigate whether coronary artery calcium (CAC) modifies the association between hormone therapy (HT) use and cardiovascular disease (CVD) events. METHODS: A total of 3,235 female participants free of clinical CVD at baseline were included from the Multi-Ethnic Study of Atherosclerosis and monitored for incident CVD. HT status was self-reported and categorized as never, former, and current users. Cox proportional hazards regression models were fit to examine the relationships between HT and CVD outcomes, with and without CAC (as categories), including standard risk factors as covariates. RESULTS: Participants were 63.4 ± 9.8 years of age, and 90% were postmenopausal. There were 1,024 (32%) current, 1,618 (50%) never, and 593 (18%) former HT users. Current HT users were significantly younger, more likely to be White, had lower prevalence of diabetes mellitus, and higher education and income levels. During the 14.4-year follow-up period, 734 deaths (14.8 per 1000 person-years) and 454 CVD events (10.1 per 1000 person-years) were identified. In multivariable Cox regression analysis including CAC, current HT use versus never use was associated with lower risk for all-cause death (hazard ratio [HR]: 0.70, 95% CI: 0.58-0.86) and in current versus former users (HR: 0.77, 95% CI: 0.61-0.98). Former users did not differ significantly from never users in risk of death or cardiovascular outcomes. Addition of CAC to adjusted models did not meaningfully modify the association between HT status and all-cause death (HR: without CAC: 0.69 [0.57-0.85]; HR with CAC: 0.70 [0.58-0.86]). CONCLUSIONS: Women who received HT have a significantly lower risk of all-cause death compared with never and former users, with CVD and coronary heart disease outcomes trending lower but not reaching statistical significance after adjustment. CAC did not modify the observed association between HT and mortality.