A new study published in the Journal of the American Medical Association suggests that postmenopausal women who took calcium channel blockers for their blood pressure for more than 10 years were 2.4 to 2.6 times more likely to develop breast cancer compared to women who did not take any hypertension medications. The study was observational and did not get into the reasons behind the increase, but experts said the findings may have major public health implications.
"While some studies have suggested a positive association between calcium channel blocker use and breast cancer risk, this is the first study to observe that long-term current use of calcium channel blockers in particular are associated with breast cancer risk," said the study.
Calcium channel blockers were the ninth most commonly prescribed drug in the United States in 2009, with over 90 million prescriptions filled, according to JAMA.
Examples include amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine and verapamil.
The drugs prevent calcium from getting into the muscles of the heart and arteries, and may widen the blood vessels and slow the heart rate.
"Other antihypertensive medications - diuretics, beta-blockers and angiotensin II antagonists - were not associated with increased breast cancer risk," said the JAMA study.
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They found that using calcium channel blockers (CCB) for 10 or more years was associated with 2.4 times higher odds of ductal breast cancer and 2.6 times higher odds of lobular breast cancer.
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"If the two- to three-fold increase in risk found in this study is confirmed, long-term CCB use would take its place as one of the major modifiable risk factors for breast cancer."
Breast cancer is the most common cancer in women worldwide. According to the National Cancer Institute, one in eight women born today will develop breast cancer in her lifetime.
Source-AFP