A study published in August 2013 suggested that postmenopausal women who took calcium-channel blockers to treat high blood pressure for 10 years or more have a higher risk of breast cancer.
Now a new, larger study suggests that calcium channel blockers DON’T increase the risk of breast cancer.
The results of the study were presented on Nov. 19, 2014 at the 2014 American Heart Association Scientific Sessions in Chicago. Read the abstract of “Long Term Use of Calcium Channel Blockers and Risk of Breast Cancer Development.”
Calcium-channel blockers are a common type of high blood pressure medicine. (Doctors call high blood pressure “hypertension.”) Medicines to treat high blood pressure are the most commonly prescribed types of medicines in the United States. In 2010, about 98 million prescriptions for calcium-channel blockers were filled. Other types of high blood pressure medicines are ACE inhibitors, beta blockers, and diuretics.
Because high blood pressure is a chronic condition -- meaning it lasts for a long time -- most people who take medicine to treat it take the medicine for a long time.
Earlier studies have looked for a possible link between high blood pressure medicines and breast cancer risk, but the studies were small and the results were mixed.
In this new study, researchers at the Intermountain Medical Center in Utah looked at the medical records of women aged 50 to 70 in two databases who had no history of breast cancer. In total, they looked at the records of more than 3,700 women. They compared women taking calcium channel blockers for many years to control high blood pressure to women who weren’t taking calcium channel blockers.
The two databases were:
- a general population medical records database
- women treated at the Intermountain Cardiac Catheterization Laboratory records database
The cardiac catheterization lab does tests on the heart, including angiograms, which check the coronary arteries. The lab also does heart valve replacement and other heart procedures.
In the general population medical records database, the researchers found that women who took calcium channel blockers had a 1.6 times higher risk of breast cancer. This risk is just slightly higher than average and is much smaller than the increase in risk reported in the 2013 study.
In the cardiac catheterization lab records database, the researchers found that women who took calcium channel blockers had a 50% LOWER risk of breast cancer.
Because of these wildly different results, the researchers believe that it’s likely that calcium channel blockers aren’t causing the change in breast cancer risk. Instead, it’s probably because the women in the general population medical records database taking calcium channel blockers had other factors that affected their breast cancer risk, including other medicines they might have been taking, smoking, alcohol use, weight, and family history.
It’s important to know that many of the risk factors for high blood pressure, including:
- being overweight
- not getting enough exercise
- drinking alcohol
are also risk factors for breast cancer.
If you take a calcium channel blocker to control high blood pressure, the results of this study are reassuring. Still, for the health of your heart and your breasts, it makes sense to minimize the risk factors you can control, including:
- eating a diet that’s low in processed foods and sugar
- avoiding alcohol
- maintaining a healthy weight
- exercising daily
- not smoking
You can learn much more about breast cancer risk and other steps you can take to minimize that risk in the Breastcancer.org Lower Your Risk section.