Shift work, hCLOCK T3111C polymorphism, and endometriosis risk

Abstract

BACKGROUND: Endometriosis, a dysplastic disease affecting approximately 5%-10% of US reproductive-age women, has been linked to exposures indicating high circulating estrogen levels. One such exposure may be night shift work, which has been associated with menstrual disruption and increased risk of 2 other estrogen-influenced diseases, breast cancer and adverse coronary events. METHODS: In this population-based case-control study, cases were 235 women aged 18 to 49 years who were enrolled in a large health-maintenance organization in the state of Washington, and who were first diagnosed with surgically-confirmed endometriotic disease between April 1, 1996 and March 31, 2001. Controls were 54..