Non-contraceptive estrogen use and the risk of gallstone disease in women.

We interviewed 102 women, ages 41-74 years who underwent gallstone surgery between January 1979 and September 1980, and 98 controls selected from the membership files of a large prepaid health care plan in Western Washington, about their past use of certain medications, reproductive history, and physical and demographic characteristics. The risk of gallstone disease among women who used estrogens for at least one year prior to diagnosis of their condition, relative to that of other women, was 1.18 (95% CI: 0.65-2.13). Standardization for the effects of age, race, obesity, parity, thiazide use, and history of high blood pressure did not alter appreciably the estimate of relative risk. Among estrogen users, the duration of use was similar in cases and controls. Our findings suggest that if non-contraceptive estrogen use is a risk factor for gallstone disease (requiring surgery) in women, its effect is very small.