Monday, May 9, 2011

Fluke or Trend? Calcium vs Heart Disease

Semmelweis.  Marshall.  Bolland?

It takes a lot of courage to go up against the establishment.  Semmelweis did this back in the 1840s to prove that washing hands would decrease puerperal fever (maternal-fetal mortality).  More recently, Marshall did this in the 1980s to prove that H pylori is the cause of peptic ulcer disease.  Now it appears that Marc Bolland and the BMJ have taken up the sword to convince all of us that too much calcium increases our risk of cardiovascular disease.

Back in February 2008, Bolland & his team noted that calcium supplementation was associated with greater risk of myocardial infarctions after randomizing 732 healthy postmenopausal New Zealand women to calcium & 739 to placebo, neither of whom received any vitamin D, over 5 years.

Then last July, Bolland & colleagues arrived at the same conclusion after performing a meta-analysis of 15 trials involving 8,151 female participants followed for close to 4 years.

Most recently, Bolland et al stirred up the hornet's nest last month by again associating calcium supplementation with cardiovascular events, regardless of whether or not vitamin D was consumed, after reviewing the available data from 16,718 female participants of the Women's Health Initiative study.

So are Bolland's findings a fluke or trend?  After 3 separate studies, it's difficult to dismiss his claims and renounce all calcium.  However, I'm concerned that he's the only one leading the charge (and that the BMJ is the only publication getting this into print).  I'll be more of a convert once others have been able to duplicate his findings - call me cynical but I've heard all too many false research findings announced as ground breaking news in our scientific assembly only to be denounced later on by their colleagues.

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