Serum 2-Methoxyestradiol, an Estrogen Metabolite, is Positively Associated with Serum HDL-C in a Population-Based Sample

Serum HDL cholesterol (HDL-C) is inversely associated with coronary artery disease, ischemic stroke, and atherosclerosis in men and women. Among postmenopausal women, oral conjugated equine estrogen (CEE) increases serum HDL-C. This is due to activation of hepatic nuclear estrogen receptors, resulting in increased HDL-C expression, as well as modulation of proteins which metabolize HDL-C. 2-methoxyestradiol (2-MeOE2), an estrogen metabolite, has several vasculoprotective effects and may play a role in HDL-C production. 2-MeOE2 inhibits HMG-CoA reductase in vitro but no study has examined the relationship between serum 2-MeOE2 and serum HDL-C. A population-based sample provided information regarding demographic characteristics and use of antihyperlipidemic medications. Serum was analyzed for 17 beta-estradiol (E2), estrogen metabolites (EMs), and lipoproteins. Results included serum EM data from 51 men and 47 postmenopausal women. Preliminary analysis revealed no correlation between 2-MeOE2 and serum HDL-C in men so the current analysis includes only women (N = 40) with no missing demographic, medication, EM, or lipoprotein data. Linear regression revealed that serum 2-MeOE2 and antihyperlipidemic medications were positively associated with serum HDL-C (beta = 0.276, P = 0.043, and beta = 0.307, P = 0.047, respectively) when age, race/ethnicity, and body mass index were held constant. Prospective studies are needed to determine if 2-MeOE2 is causally related to HDL-C in women.