Effects of alcohol ingestion on estrogens in postmenopausal women

Objective.-To determine if moderate alcohol drinking increases circulating estradiol levels in postmenopausal women who are taking estrogen replacement. Design.-Randomized, double-blind, placebo-controlled crossover study of the effects of alcohol ingestion on plasma estradiol and estrone. Setting.-Inpatient Clinical Research Center. Participants.-Twelve healthy postmenopausal women receiving oral estrogen (estradiol, 1 mg/day) and progestin (medroxyprogesterone acetate) replacement therapy were compared with 12 postmenopausal women who were not using estrogen replacement therapy (ERT). Intervention.-Each group drank alcohol (0.7 g/kg) and an isoenergetic (isocaloric) placebo (randomized sequence) on consecutive days. Women who were taking ERT were studied during the estrogen-only portion of their replacement cycle, and estrogen was administered each evening at 2100 hours. Main Outcome Measure.-The impact of alcohol ingestion on plasma estradiol and estrone levels. Results.-Alcohol ingestion lead to a 3-fold increase in circulating estradiol in women on ERT; however, alcohol did not change estradiol significantly in control women who were not on ERT. In women using ERT, estradiol levels increased from 297 to 973 pmol/L (81 to 265 pg/ml) within 50 minutes (P<.001) during the ascending limb of the blood alcohol curve and remained significantly above baseline for 5 hours (P<.001). No significant increase in circulating estrone was detected in either group, However, estrone levels decreased after alcohol and placebo in women on ERT (P<.05). Blood alcohol levels did not differ significantly in women who used ERT and those who did not. Peak blood alcohol levels of 21 mmol/L were attained in each of the 2 groups within 50 to 60 minutes after drinking began. Changes in estradiol were significantly correlated with changes in blood alcohol levels on both the ascending (P<.001) and descending (P<.001) limb of the blood alcohol curve. Conclusions.-Acute alcohol ingestion may lead to significant and sustained elevations in circulating estradiol to levels 300% higher than those targeted in clinical use of ERT, Potential health risks and benefits of the interactions between acute alcohol ingestion and ERT should be further evaluated.