Use of Antihypertensive Medications and Breast Cancer Risk Among Women Aged 55 to 74 Years
What are the associations between various classes of antihypertensive medications and risk for invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) breast cancers among postmenopausal women?
This was a population-based case-control study conducted in the Seattle–Puget Sound metropolitan area. Participants were women ages 55-74 years, 880 of them with IDC breast cancer and 1,027 with ILC breast cancer, diagnosed between January 2000 and December 2008. A total of 856 age-matched women with no cancer served as controls. Through a series of structured questions, detailed histories were obtained of hypertension, heart disease, and all uses of angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, beta-blockers, calcium-channel blockers, diuretics, and combination antihypertensive preparations regardless of indication, including beginning and ending dates, drug name, dose, route of administration, pattern of use (number of days per month), and indication.
Both cases and controls had similar distributions of age and annual household income and histories of hypertension, heart disease, and hypercholesterolemia. Compared with control women and IDC case patients, ILC case patients were somewhat less likely to be African American, more likely to be college graduates, and less likely to be obese (body mass index ≥30.0 kg/m2). Both IDC and ILC case patients were somewhat more likely to have a first-degree family history of breast cancer, to be current alcohol users, and to be current smokers. The proportion of current users of combined estrogen and progestin menopausal hormone therapy was highest among ILC case patients, intermediate among IDC case patients, and lowest among controls. Current use of calcium-channel blockers for 10 or more years was associated with higher risks of IDC (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.2-4.9; p = 0.04 for trend) and ILC (OR, 2.6; 95% CI, 1.3-5.3; p = 0.01 for trend). This relationship did not vary appreciably by type of calcium-channel blocker used (short-acting vs. long-acting, dihydropyridines vs. nondihydropyridines). In contrast, use of diuretics, beta-blockers, and angiotensin II antagonists were not associated with risk.
The investigators concluded that this was the first study to observe that long-term current uses of calcium-channel blockers were associated with breast cancer risk. Additional research is needed to confirm this finding and to evaluate potential underlying biological mechanisms.
Use of calcium channel blockers as antihypertensive medications is very common. Given the high prevalence of hypertension among postmenopausal women, understanding the risks related to antihypertensive medications are important. As the authors suggest, further research is needed to confirm the findings observed in this study.
Keywords: Angiotensin Receptor Antagonists, Body Mass Index, Case-Control Studies, Carcinoma, Hypercholesterolemia, Hormone Replacement Therapy, Hypertension, Calcium Channel Blockers
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