Long-Term Use of Antihypertensive Agents and Risk of Breast Cancer: A Population-Based Case–Control Study

INTRODUCTION: To evaluate the risk of breast cancer associated with long-term use of antihypertensive agents (AHs) in Taiwanese women with hypertension. METHODS: A search of the Taiwan National Health Insurance Research Database identified 330,699 patients with hypertension who were treated with antihypertensive drugs between January 1, 1998 and December 31, 2011. Logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) between the use of AHs and breast cancer risk, adjusted for other types of antihypertensive drugs, statins and co-morbidities. RESULTS: Among the AHs used to treat the hypertensive women enrolled in our study, our analysis revealed that those treated with one specific particular class of beta-blockers (beta-1 selective beta-blockers) had an increased risk for breast cancer. We also found that the ever-use of calcium channel blockers (CCBs; i.e. for 13 years) was associated with breast cancer in an adjusted model (OR 1.09; 95% CI 1.03–1.16). However, the use of nonselective beta-blockers, selective and nonselective alpha-blockers, angiotensin-converting enzyme inhibitors and angiotensin II antagonists were not associated with breast cancer risk. CONCLUSION: Based on the results of our analysis, long-term use of CCBs or beta-1 selective beta-blockers are likely to be associated with the risk of breast cancer. Further large comprehensive population-based studies to support our findings are required for confirmation of this conclusion.