Hormonal and reproductive factors and pancreatic cancer risk: A prospective cohort study

Objectives: We examined pancreatic cancer risk in association with hormonal and reproductive factors in a prospective cohort study of 89,835 Canadian women, aged 40-59 at recruitment, who were enrolled in the National Breast Screening Study (NBSS). Methods: Linkages to national cancer and mortality databases yielded data on cancer incidence and deaths of all causes, respectively, with follow-up ending between 1998 and 2000. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between hormonal and reproductive factors and risk of pancreatic cancer. Results: During a mean of 16.4 years of follow-up, we observed 187 incident pancreatic cancer cases. Compared with women who were premenopausal at baseline, postmenopausal women were at significantly increased risk of pancreatic cancer (odds ratio = 2.44, 95% confidence interval [CI] = 1.45-4.09). Age at first livebirth, parity, age at menarche, use of oral contraceptive, and use of hormone replacement therapy (HRT) were not associated with altered pancreatic cancer risk in our study population. However, among parous women, risk increased with increasing parity. Conclusion: Other than the increased risk among postmenopausal women, the present study provides little support for associations with hormonal factors. Additional prospective data are needed.