Sex differences in the incidence and manifestation of cardiovascular disease (CVD)
suggest the involvement of sex hormones in disease pathogenesis. Coronary artery calcium
(CAC) and its progression, measured by non-contrast cardiac computed tomography, are
markers of subclinical atherosclerosis and predict CVD, even among low-risk women.
We hypothesized that sex hormone levels were associated with CAC progression among
women in the Multi-Ethnic Study of Atherosclerosis. We studied 2,759 post-menopausal
women (age 65±9 years), free of baseline CVD, with baseline serum sex hormones and
CAC measured at Exam 1 (2000–2002). Of this sample, 2,427 had ≥1 follow-up CAC measurement
through Exam 5 (2010–2012). Using mixed effects linear regression methods, we tested
change in log[CAC+1] score by log[sex hormone] levels (continuous, comparing the 90th
versus 10th percentiles). Models adjusted for demographics, lifestyle factors, cardiovascular
risk factors, hormone therapy, and years since menopause. At baseline, we found no
associations between sex hormones and prevalent CAC. Over a median of 4.7 years, in
fully-adjusted models, women with higher free testosterone levels had a greater relative
CAC progression ratio (95% CI) [1.26 (1.011.56)], whereas higher sex hormone binding
globulin (SHBG) was associated with lower progression risk [0.80 (0.64–0.99). No associations
were seen for total testosterone, estradiol, or dehydroepiandrosterone. A more androgenic
hormone profile of higher free testosterone and lower SHBG is associated with a greater
CAC progression up to 10-years in post-menopausal women. Sex hormone levels may help
identify women at increased risk for CVD who may benefit from additional risk-reducing
strategies.