Calcium Supplements Linked to Heart Problems
Reported April 25, 2011
(Ivanhoe Newswire) -- The risk of having a heart attack and other cardiovascular
events, particularly in older women, may be influenced by their calcium
supplements with or without vitamin D, according to a new study.
Older postmenopausal women are often prescribed calcium supplements to maintain
bone health; some contain vitamin D, and others do not. The Woman’s Health
Initiative (WHI) study was conducted over a seven-year span evaluating more than
36,000 women to determine the cardiovascular effects of taking calcium with
vitamin D. However, many of the women in the study were previously taking
personal calcium supplements, and there became a concern for obscured results.
Professor Ian Reid from the University of Auckland along with his team of
researchers reanalyzed the WHI study results in an attempt to estimate the
effects of calcium supplements with and without vitamin D.
Data was gathered from 16,718 women in the study who were not previously taking
personal calcium. The researchers found an increased risk of cardiovascular
events, especially heart attacks for women taking calcium with vitamin D
supplements. On the other hand, the study revealed women who were previously
taking personal calcium and vitamin D supplements did not have any changes in
their cardiovascular risks.
High blood calcium levels are linked to hardening of the arteries
(calcification), and the researchers believe after taking the calcium
supplement, an abrupt change in blood calcium levels produce an adverse effect.
Also, data from 13 other studies involving 29,000 people have shown consistent
increases in heart attack and stroke related to taking calcium supplements, with
or without vitamin D.
Others are skeptical about the evidence linking calcium supplements with
cardiovascular problems. In an accompanying editorial, Professors Bo Abrahamsen
and Opinder Sahota are quoted as saying that due to the study’s limitations: "It
is not possible to provide reassurance that calcium supplements given with
vitamin D do not cause adverse cardiovascular events or to link them with
certainty to increased cardiovascular risk. Clearly, further studies are needed,
and the debate remains ongoing."