JAMA Internal Medicine: Adverse Drug Effects Topic Collection

Dietary and Supplemental Calcium Intake and Cardiovascular Disease Mortality The National Institutes of Health–AARP Diet and Health Study Calcium Intake and CVD Mortality

Xiao Q, Murphy RA, Houston DK, et al. — Mon, 22 Apr 2013 00:00:00 GMT

Importance

Calcium intake has been promoted because of its proposed benefit on bone health, particularly among the older population. However, concerns have been raised about the potential adverse effect of high calcium intake on cardiovascular health.

Objective

To investigate whether intake of dietary and supplemental calcium is associated with mortality from total cardiovascular disease (CVD), heart disease, and cerebrovascular diseases.

Design and Setting

Prospective study from 1995 through 1996 in California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania and the 2 metropolitan areas of Atlanta, Georgia, and Detroit, Michigan.

Participants

A total of 388 229 men and women aged 50 to 71 years from the National Institutes of Health–AARP Diet and Health Study.

Main Outcome Measures

Dietary and supplemental calcium intake was assessed at baseline (1995-1996). Supplemental calcium intake included calcium from multivitamins and individual calcium supplements. Cardiovascular disease deaths were ascertained using the National Death Index. Multivariate Cox proportional hazards regression models adjusted for demographic, lifestyle, and dietary variables were used to estimate relative risks (RRs) and 95% CIs.

Results

During a mean of 12 years of follow-up, 7904 and 3874 CVD deaths in men and women, respectively, were identified. Supplements containing calcium were used by 51% of men and 70% of women. In men, supplemental calcium intake was associated with an elevated risk of CVD death (RR_{>1000 vs 0 mg/d}, 1.20; 95% CI, 1.05-1.36), more specifically with heart disease death (RR, 1.19; 95% CI, 1.03-1.37) but not significantly with cerebrovascular disease death (RR, 1.14; 95% CI, 0.81-1.61). In women, supplemental calcium intake was not associated with CVD death (RR, 1.06; 95% CI, 0.96-1.18), heart disease death (1.05; 0.93-1.18), or cerebrovascular disease death (1.08; 0.87-1.33). Dietary calcium intake was unrelated to CVD death in either men or women.

Conclusions and Relevance

Our findings suggest that high intake of supplemental calcium is associated with an excess risk of CVD death in men but not in women. Additional studies are needed to investigate the effect of supplemental calcium use beyond bone health.

Are Calcium Supplements Harmful to Cardiovascular Disease? Comment on “ Dietary and Supplemental Calcium Intake and Cardiovascular Diseases Mortality: The National Institutes of Health–AARP Diet and Health Study” Calcium and CVD

Larsson SC. — Mon, 22 Apr 2013 00:00:00 GMT

Calcium is the most abundant mineral in the body and is crucial for the maintenance of strong bones and teeth. Furthermore, calcium is required for the body's basic functions, such as nerve transmission, blood clotting, blood pressure, muscle contraction, enzyme activation, and hormone regulation. Although when most people think of calcium they think of dairy sources, nondairy foods, such as spinach, kale, soybeans, and white beans, also contain calcium. Calcium is available as dietary supplements and is often taken in combination with vitamin D to improve calcium absorption. Many women are encouraged to take calcium supplements. Approximately 43% of the US population uses dietary supplements that contain calcium. Given the extensive use of calcium supplements, any beneficial or harmful effect of supplemental calcium on health is of great clinical and public health importance.

Surrogate Outcomes in Clinical Trials A Cautionary Tale Surrogate Outcomes in Clinical Trials

Svensson S, Menkes DB, Lexchin J. — Mon, 22 Apr 2013 00:00:00 GMT

Surrogate outcomes are often used as proxies for hard clinical outcomes, as they enable smaller, faster, and thus cheaper clinical trials. In addition, pharmaceutical companies argue that using surrogates means that fewer patients are exposed during testing, and beneficial new medications reach the market faster. Their main disadvantage is that favorable effects on surrogates do not automatically translate into benefits to health.

Placing Acupuncture in Perspective

Ziegelstein RC. — Mon, 22 Apr 2013 00:00:00 GMT

The individual patient data meta-analysis by Vickers et al reported that acupuncture is effective for the treatment of chronic pain but that the effects are “relatively modest.” The authors base their conclusions on a well-conducted analysis of randomized controlled trials that compared acupuncture with sham or no-acupuncture controls. However, I believe that 2 important issues are not considered in their article or in the Invited Commentary that would help place acupuncture in better perspective for clinicians who wish to consider this modality as a possible treatment for chronic pain.