Pigmentary traits, family history of melanoma and the risk of endometriosis: a cohort study

Background Endometriosis has been associated with a higher risk of cutaneous melanoma, but the mechanisms underlying this association are un-known. Some constitutional factors known to influence melanoma risk have been associated with endometriosis in some retrospective studies. However, prospective data are scarce, and more research is needed to confirm this potentially novel endometriosis risk profile. Methods To investigate the relationships between pigmentary traits, family history of melanoma and endometriosis risk, we analysed data from the Nurses ’ Health Study II, a cohort of 116 430 female US nurses aged 25–42 years at inclusion in 1989. Data were collected every 2 years with 20 years of follow-up for these analyses. We used Cox proportional hazards regression models to compute relative risks (RRs) and 95 % confidence intervals (CIs). Results During 1 212 499 woman-years of follow-up, 4763 cases of laparo-scopically-confirmed endometriosis were reported among premeno-