Abstract
Endometrial cancer risk is increased by estrogens unopposed by progesterone. In premenopausal women, androgen excess is often associated with progesterone insufficiency, suggesting that premenopausal androgen concentrations may be associated with risk. In a case-control study nested within three cohorts, we assessed the relationship between premenopausal androgens and risk of endometrial cancer (161 cases and 303 controls matched on age and date of blood donation). Testosterone, DHEAS, androstenedione, and SHBG were measured in serum or plasma. Free testosterone was calculated from testosterone and SHBG. We observed trends of increasing risk across tertiles of testosterone (ORT3-T1 = 1.59, 95 % CI = 0.96, 2.64, p = 0.08) and free testosterone (ORT3-T1 = 1.76, 95 % CI = 1.01, 3.07, p = 0.047), which were not statistically significant after adjustment for body mass index (BMI). There was no association for DHEAS, androstenedione, or SHBG. There were significant interactions by age at diagnosis (<55 years, n = 51 cases; ≥55 years, n = 110 cases). Among women who were ≥55 years of age (predominantly postmenopausal) at diagnosis, the BMI-adjusted OR was 2.08 (95 % CI = 1.25, 3.44, p = 0.005) for a doubling in testosterone and 1.55 (95 % CI = 1.04, 2.31, p = 0.049) for a doubling in free testosterone. There was no association among women aged <55 years at diagnosis, consistent with the only other prospective study to date. If pre- and post-menopausal concentrations of androgens are correlated, our observation of an association of premenopausal androgens with risk among women aged ≥55 years at diagnosis could be due to the effect on the endometrium of postmenopausal androgen-derived estrogens in the absence of progesterone, which is no longer secreted.