Calcium Supplements Could Raise Heart Risks in Postmenopausal Women
Tuesday, January 15, 2008; 12:00 AM
TUESDAY, Jan. 15 (HealthDay News) -- The calcium tablets taken by millions of postmenopausal women to reduce their risk of osteoporosis may be contributing to an increase in heart attack and other cardiovascular problems.
The findings might mean doctors shouldn't prescribe the supplement so freely.
"There are data from other recent studies showing an upward trend in heart attacks with calcium use, so we think this is likely to be a real finding," said study senior author Dr. Ian Reid, of the faculty of medical and health sciences at the University of Auckland in New Zealand. "It is likely that this is primarily a problem for elderly women, because they are more likely than younger subjects to have prevalent coronary heart disease. Therefore, it seems wise to advise against calcium supplementation in those over the age of 70 years and in those known to have coronary heart disease."
"This is the most upsetting study. Osteoporosis is a major issue that we're trying to deal with as we get older, and we've been talking about calcium supplementation to prevent osteoporosis," added Dr. Susan Steinbaum, director of Women and Heart Disease at the Heart and Vascular Institute at Lenox Hill Hospital in New York City. "There's a huge group of women trying to stay healthy [by taking calcium], and now we're being told that, in fact, this is something that can hurt you... It's very, very frustrating."
Steinbaum added, however, that while the results can't be ignored, the study may not be large enough to justify taking women off calcium supplements just yet. "Preventive medicine is not something that can be standardized per person," she said. "It needs to be individualized."
The pharmaceutical industry does not necessarily agree with these points.
In a statement, Pamela Mason, a nutritionist and spokeswoman for the Health Supplements Information Service, which is funded by several pharmaceutical companies, said, "Calcium is an essential mineral, vital for bone health and nerve and muscle function. The results of this study certainly do not suggest that people should lower their calcium intakes below the RDA (Recommended Daily Amount). Indeed, because of the importance of calcium, it remains imperative for people to achieve the RDA."
Still another expert weighed in on the study's importance.
"This suggests very weakly that these other effects of calcium supplementation need to be paid attention to. It's a very good study in that sense," said Dr. Bernard Roos, director of geriatrics research at the University of Miami Miller School of Medicine and the Miami VA. "The effect they're reporting is very small. I don't believe that it should change people's behavior. I believe the conclusion that they drew is fair: This should just alert you to the possibility that it's a potentially detrimental effect."
Roos also pointed out that healthy postmenopausal women, such as those participating in this analysis, would not be expected to be taking calcium anyway. "Healthy postmenopausal women, by definition, don't have osteoporosis, so if you don't have osteoporosis, why are you so worried about taking anything if you're healthy?" he said.
Prior evidence had indicated that calcium supplementation might protect against vascular disease, because it increases the ratio of HDL or "good" cholesterol to LDL or "bad" cholesterol by almost 20 percent. There is also evidence that calcium reduces blood pressure (albeit only briefly). And people who live in areas with calcium-rich water seem to have a lower risk of cardiovascular problems.
But the overall evidence, especially in older women, is inconsistent, stated the study authors.