Increased breast cancer risk with long-term use of calcium-channel blockers for hypertension

Long-term use of a calcium-channel blocker to treat hypertension (high blood pressure) is associated with higher breast cancer risk, according to a study published by JAMA Internal Medicine, a Journal of the American Medical Association Network publication and reported by EurekAlert.

Antihypertensive medications are the most commonly prescribed class of drugs in the USA and in 2010 totaled an estimated 678 million filled prescriptions, Christopher Li, of the Fred Hutchinson Cancer Research Center, Seattle, and colleagues write in the study background. "Evidence regarding the relationship between different types of antihypertensives and breast cancer risk is sparse and inconsistent, and prior studies have lacked the capacity to assess impacts of long-term use," the study notes.

The population-based study in the three-county Seattle-Puget Sound metropolitan area included women aged 55 to 74 years: 880 of the women had invasive ductal breast cancer, 1,027 had invasive lobular breast cancer and 856 of them had no cancer and served as the control group. Researchers measured the risk of breast cancer and examined the recency and duration of use of antihypertensive medications.