People who take medications to lower their blood pressure may be raising their risk for developing early-stage, age-related macular degeneration (AMD), according to a recent study.
Vasodilators help lower blood pressure by opening blood vessels. Some act directly on blood vessels, making them relax and become wider. Others affect processes in the body that cause the blood vessels to tighten and become narrower.
Certain calcium channel blockers not only dilate blood vessels but also lessen the heart's mechanical and electrical functions, which in turn can enhance their blood-pressure-lowering action and may also help regulate irregular heart rhythms.
The study, by researchers from the University of Wisconsin School of Medicine and Public Health, looked at data from a long-term study of nearly 5,000 residents of Beaver Dam, Wisconsin.
While it does not lead to complete blindness, the loss of central vision in AMD can interfere with the ability to see faces, drive, read, write, or do close work, such as cooking or fixing things around the house.
The researchers found that after adjusting for age, sex, and other factors, using any vasodilator was associated with a 72 percent greater risk of developing early-stage AMD. Among people who were not taking vasodilators, an estimated 8.2 percent developed signs of early AMD. In comparison, among those taking a vasodilator medication, 19.1 percent developed the disease.
Taking oral beta blockers was associated with a 71 percent increase in the risk of a more advanced and vision-threatening form of the disease, neovascular AMD.
“As significant as these results may be, it's important that they be replicated first, and if possible tested in a clinical trials setting before changing anyone's medication regimens,” said Ronald Klein, M.D., M.P.H., lead researcher of the study in a statement. “Further research is needed to determine the cause of these increased risks.”
AMD involves the deterioration of the eye's macula, which is responsible for the ability to see fine details clearly. It affects an estimated 11 million people in the United States.
While it does not lead to complete blindness, the loss of central vision in AMD can interfere with the ability to see faces, drive, read, write, or do close work, such as cooking or fixing things around the house. So it can have a big effect on seniors' ability to live independently.
Age is a key risk factor for AMD, but there are others, including hereditary risk and smoking. Some studies have also found an association between AMD and high blood pressure, but this has been inconsistent.
The study appears in Ophthalmology.