Older people often take daily calcium supplements to help protect against brittle and aging bones, but new research suggests that may do more harm than good, potentially increasing the risk of vision loss.
In a study published last month in the medical journal JAMA Ophthalmology, researchers found that people who take calcium supplements had a higher likelihood of developing age-related macular degeneration.
Nearly 3,200 participants of the National Health and Nutrition Examination Survey (NHANES) were questioned concerning their calcium supplementation in the 30 days prior to enrollment of the study. All participants were over the age of 40 and the self-reported survey was conducted between 2007 and 2008.
The participants were asked about both calcium supplements and antacid use. They were then evaluated for the presence or absence of age-related macular degeneration by fundus photography.
Nearly 250 patients, approximately eight percent of the group, was diagnosed with age-related macular degeneration. Those diagnosed with the disease had an average age of 67 years or older.
Researchers also found patients who did not have age-related macular degeneration had an average age of 55 years.
Overall, participants who took more than 800 mg a day of calcium supplements were twice as likely to be diagnosed with age-related macular degeneration than those who were not taking calcium supplements at all.
Age-related macular degeneration is an eye condition that causes severe vision loss. Many older people develop the condition as a part of the natural aging process. It will often begin and affect only one eye, but may later affect both eyes.
Research published in 2011 in the British Medical Journey revealed calcium supplement use in post-menopausal women increased their risk of heart attack. The study found women taking calcium supplements had a 22% increased risk of suffering a heart attack, compared to women who did not take the supplements.
Researchers also found the association between taking calcium supplements and age-related macular degeneration was stronger in older participants than it was in younger participants.
“The stronger association in older individuals may be due to relatively longer duration of calcium supplementation,” wrote study authors.
While the study does not prove cause and effect between calcium supplements and age-related macular degeneration, the results of the study held true even when other factors, such as age, sex, smoking, alcohol use, cataract surgery and other health factors were considered.
A limitation of the study may be the nature of the study itself. Since participants were asked to self-report their use of calcium supplements, some patients may not have accurately reported their use. In addition, calcium intake from food and drinks was not considered either.
A study published in 2012 revealed a link between regular aspirin use and the development of neovascular macular degeneration, a rare form of eye disease also known as “wet” macular degeneration. The disease can cause blood vessels to bleed and leak, eventually blurring vision. Researchers found patients with 10 years of aspirin use or more had a higher risk of developing the eye disease.