A recent study published by a group of scientists at the University of Auckland in New Zealand suggests that taking calcium supplements may be harmful to heart health in older, post-menopausal women. The authors claim they found “upwards trends” in the relative risk for heart attack, stoke or sudden death in women (average age of 74 years) taking calcium pills for five years compare with similar-aged women who did not use the supplements over the same period of time.
The study has been challenged in several editorial responses to the research, however. Other scientists reviewing the original report claim that the authors overstated their findings, applied loose standards to their statistical analysis, ignored factors such as smoking status, previous heart conditions and previous use of hormone replacement therapy, and did not monitor vitamin D levels in the patients. Low levels of vitamin D have been associated with an increase in cardiovascular disease.
The “potentially detrimental effect of calcium” stated in the authors’ conclusion misrepresents the actual data of the report, according to Wendy S. Biggs, MD, Associate Editor of Journal Watch for Women’s Health. “If we are to practice evidence-based medicine, then we need to remain true to the evidence,” she states.
Dr. Biggs worries that people reading only the abstract of such a paper and not looking at critical details of the report will come away with a misinformed conclusion.
Bolland, M. et al, 2008. “Vascular Events in Healthy Older Women Receiving Calcium Supplementation: Randomised Controlled Trial,” BMJ.
Biggs, W., 2008. “Misrepresentation of Study Data,” editorial in Rapid Responses, BMJ.