Proton pump inhibitors reduce breast cancer risk in gastric ulcer patients: A population-based cohort study.

We aim to evaluate breast cancer risk relating to PPIs usage in women with peptic ulcer. From 2000 to 2013, incidence rates of breast cancer were compared between the two cohorts (with or without PPIs). Each study cohort consisted of 4838 women. The incidence density rate of breast cancer in the PPI cohort was 0.29 that in the comparison cohort (10.0 vs 31.6 per 10 000 person-years), with an adjusted HR (hazard ratio) of 0.32 (95% CI = 0.20-0.49) for the PPI cohort. In conclusion, the medication of PPIs is associated with reduced breast cancer risk for women with gastric ulcer.