Medicine
Concerns about calcium supplements
Until recently, the idea that calcium-containing supplements, which more than half of older adults in the U.S. consume regularly, could be harmful would have seemed absurd. Primary care clinicians have long recommended calcium supplements to reduce the risk of osteoporotic fractures in adults who are unable to meet the Institute of Medicine's Dietary Reference Intakes through diet alone. However, a large prospective study published this week in
JAMA Internal Medicine demonstrated a statistically significant association between supplemental calcium (as opposed to dietary calcium) intake and a 20 percent higher relative risk of death from cardiovascular disease in men.
This troubling finding adds to the evidence base that suggests harmful cardiovascular effects of calcium-containing supplements. A timely pair of editorials in the February 1st issue of
American Family Physician debates the population-level risk of widespread calcium supplementation. Arguing that this potential risk should be a serious concern, Drs. Ian Reid and Mark Bolland review the results of their previous randomized trial and meta-analysis that found 20 to 30 percent increases in the incidence of acute myocardial infarction in adults taking calcium supplements. In their view, these adverse effects are not worth the potential benefits to bone health:
In both of our meta-analyses, calcium supplementation was more likely to cause vascular events than to prevent fractures. Therefore, the bolus administration of this micronutrient should be abandoned in most circumstances, and patients should be encouraged to obtain their calcium intake from an appropriately balanced diet. For those at high risk of fracture, effective interventions with a fully documented safety profile superior to that of calcium are available. We should return to seeing calcium as an important component of a balanced diet and not as a low-cost panacea to postmenopausal bone loss.In the second editorial, Dr. Rajib Bhattacharya points out that the Women's Health Initiative and other randomized trials did not indicate that calcium supplements increased cardiovascular risk. He argues that secondary analyses of trials designed with other primary outcomes in mind may have predisposed these analyses to unforeseen bias, and that there is "no compelling evidence" that calcium supplements at usual doses pose dangers to heart health.
Notably, a draft recommendation statement released by the U.S. Preventive Services Task Force last June stated that there was insufficient evidence that vitamin D and calcium supplementation prevent fractures or cancer in otherwise healthy older adults. Although the only adverse effects of supplements mentioned in the Task Force's evidence review were renal and urinary tract stones, none of the reviewed studies were specifically designed to assess cardiovascular harms. Is it time to abandon routine calcium supplementation in healthy adults? If not, what additional evidence do we need?
**
The above post first appeared on the AFP Community Blog.
-
Is Vitamin D Supplementation Good For Anything?
For as long as I can remember, throughout medical training and clinical practice, the message from my mentors and colleagues about vitamin D supplements was the same: the sooner patients started taking them, the better to prevent osteoporosis and fractures...
-
The Top Ten Common Sense Posts Of 2013 (yes, You Read That Right)
You know how Facebook periodically offers you a #TBT photo of a memory that you posted two or more years ago? Well, while I continue working on another top 10 list (of my favorite population health and health care books of 2015), here are links to and...
-
Book Review: "ending Medical Reversal" Is Revolutionary
The take-home message of the first lecture of my first clinical clerkship (Obstetrics and Gynecology) was that we should prescribe supplemental estrogen to all postmenopausal women to prevent cardiovascular disease. That lecture happened in 1999. Less...
-
The Best Recent Posts You May Have Missed
Every other month or so, I post a list of my top 5 favorite posts since the preceding "best of" list on this blog, for those of you who have only recently started reading Common Sense Family Doctor or don't read it regularly. Here are my favorites...
-
Is Vitamin D Vastly Overrated?
Vitamin D seems to be all the rage in medicine these days. A family physician colleague commented to me last week that the laboratory test for vitamin D deficiency is becoming the most frequently ordered test in his practice. This clinical bandwagon is...
Medicine