POSTMENOPAUSAL ESTROGEN THERAPY AND THE RISK FOR DEVELOPING SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective: To examine the relation between postmenopausal hormone use and development of systemic lupus erythematosus. Design: Prospective c ohort study. Setting: Nurses' Health Study. Patients: 69 435 women age d 30 to 55 years in 1976 who reported that they had completed menopaus e and did not have systemic lupus erythematosus or any connective tiss ue disease were followed every 2 years from 1976 to 1990. These women were classified as never- or ever-(current and past) users of postmeno pausal hormones. Measurements: Incidence rates of systemic lupus eryth ematosus and classification criteria from the American College of Rheu matology that were confirmed by chart review. Results: With never-user s of postmenopausal hormones as the reference group, age-adjusted rela tive risks for systemic lupus erythematosus (n = 45 women) were 2.1 (9 5% CI, 1.1 to 4.0) for ever-users, 2.5 (CI, 1.2 to 5.0) for current us ers, and 1.8 (CI, 0.8 to 4.1) for past users. A proportional increase in the risk for systemic lupus erythematosus was observed that was rel ated to the duration of use of postmenopausal hormones (test for trend , P = 0.011). Conclusions: Postmenopausal hormone therapy is associate d with an increased risk for developing systemic lupus erythematosus.