The role of hormonal factors in lymphoid neoplasms etiology remains unclear. Previous studies have yielded conflicting results, been underpowered to assess many lymphoma subtypes, or lacked detailed information on relevant exposures. Within the European Prospective Investigation into Cancer and Nutrition cohort, we analyzed comprehensive data collected at baseline (1992-2000) on reproductive factors and exogenous hormone use among 343,458 women, including 1,427 incident B-cell non-Hodgkin lymphomas (NHL) and its major subtypes identified after a mean follow-up of 14 years (through 2015). We estimated hazard ratios and 95% confidence intervals using multivariable proportional hazards modeling. Overall, we observed no statistically significant associations between parity, age at first birth, breastfeeding, oral contraceptive use or ever use of postmenopausal hormone therapy and risk of B-cell NHL or its subtypes. Women who had a surgical menopause had a 51% higher risk of B-cell NHL (based on 67 cases) compared with natural menopause (hazard ratio=1.51, 95% confidence interval=1.17, 1.94). Given that this result may be due to chance, our results provide little support for the hypothesis that sex hormones play a role in lymphomagenesis.
Am J Epidemiol