Menopausal hormone therapy and pancreatic cancer risk in women: a population-based matched cohort study.

Abstract

The role of menopausal hormone therapy (MHT) in the development of pancreatic cancer is inconclusive owing to small studies and lack of proper study design. This population-based matched cohort study included all Swedish women who used systemic MHT between 1 July 2005 and 31 December 2012. For each user of MHT, three never-users of MHT were randomly selected, matched for childbirth, history of thromboembolic events, and previous hysterectomy, as well as for year of birth, diabetes, obesity, and smoking- or alcohol-related disorders. Multivariable conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between MHT use and pancreatic cancer. The effect of MHT duration on pancreatic cancer development was calculated using multivariable Poisson regression. There were 290,186 ever-users of MHT and 870,165 matched never-users. During the follow-up, 311 (0.0011%) ever-users of MHT and 1220 (0.0014) never-users developed pancreatic cancer. In a multivariable adjusted model, ever-users had a 23% reduced risk (OR 0.77; 95% CI: 0.68-0.87) of pancreatic cancer. This risk decreased by 35% (incidence rate ratio (IRR) 0.65; 95% CI: 0.33-1.27) in women who used MHT 1-2 years and by 60% (IRR 0.40; 95% CI: 0.18-0.88) in women who used MHT ≥ 3 years compared to women with <1 year of MHT use. The type of MHT did not change the results. Systemic MHT use might reduce the risk of pancreatic cancer.