Menstrual and reproductive factors and risk of renal cell cancer in the Multiethnic Cohort.

A relationship between female reproductive and menstrual factors, including exogenous hormone use, and renal cell cancer (RCC) has been hypothesized, but supporting epidemiologic evidence is limited and inconsistent. Here, the association of reproductive and menstrual factors with RCC risk was examined among 106,036 Hawaii-Los Angeles Multiethnic Cohort female participants who entered the cohort between 1993 and 1996. During an average 10.6 years of follow-up, 229 RCC cases were identified among these women. Data on known and potential risk factors were obtained from the baseline questionnaire. Relative risks and 95% confidence intervals for RCC associated with each factor were estimated using Cox proportional hazard models stratified by race/ethnicity, study center, and menopausal status and adjusted for age and several confounding factors. We found no evidence of association between RCC and parity, age at first birth, age at menarche, age and type of menopause (hysterectomy or bilateral oophorectomy), use and duration of oral contraceptive, and type and duration of postmenopausal hormone use. Our results do not support the hypothesis that hormone-related factors play an etiologic role in RCC among women.