COLUMBUS — A study showing an 86 percent higher rate of heart attacks in people who take calcium supplements shouldn't prompt rash decisions to abandon the bone-strengtheners, experts say.
The research, which came out of a study of cancer, was performed by German and Swiss researchers who analyzed nearly 24,000 people 35 to 64 years old for 11 years.
They found some good news regarding calcium and heart attacks: Those who consumed a moderately high amount of calcium per day in their food and beverages (820 milligrams on average) had a significantly lower risk of heart attack.
But the researchers also found something that troubled them: People who took calcium supplements had a higher risk of a heart attack.
The researchers did not collect information regarding the dosage taken by supplement-takers.
The research was published this week in the journal Heart. It was the first study of its kind to show that calcium supplements might increase the risk of a heart attack, the authors said.
The study is provocative enough that it might lead to more research specifically designed to look at calcium and heart attacks, but it's not strong enough to change doctors' recommendations, said Dr. Steven Yakubov, a cardiologist at Riverside Methodist Hospital.
One weakness of the study is that the cardiovascular analysis was a sidebar to a larger study looking at cancer, Dr. Yakubov said.
Furthermore, the study didn't adequately account for differences between the supplement and no-supplement groups, including whether they smoked, Dr. Yakubov said.
Calcium's bone-health benefits are undisputed and are important to remember, considering the burden of osteoporosis in the United States, said Dr. Keith Hruska, president of the American Society for Bone and Mineral Research and a kidney specialist at Washington University in St. Louis.
"A lot of Americans are taking calcium supplements; what I would say is they shouldn't stop," Dr. Hruska said. "It's hard to understand why calcium in the diet can reduce the risk, but supplements increase the risk."
The study's authors mention previous research that showed supplements lead to a spike in the calcium level in the blood, which doesn't happen with dietary calcium.
But they draw no direct conclusions about what led to the discrepancy.
The study is important in that "it opens our eyes, and maybe we should scrutinize the importance of taking supplements," said Dr. Laxmi Mehta, clinical director of the Women's Cardiovascular Health Clinic at Ohio State University's Wexner Medical Center.