Friday, July 30, 2010

CALCIUM SUPPLEMENTS AND YOUR HEART

In my many years in private practice, almost all my old dears that I see are on calcium pills, either prescribed by their GPs for osteoporosis and " foong supp" or taken on the advise of a friend or a friend of a friend. It is true that bone density scans are now commonly done in many urban centers and osteoporosis is very common in post-menopausal women. So calcium supplements are almost routinely prescribed. There are also milk formulations with added calcium, and many other food products with added calcium, supposedly for the post-menopausal.
Well, in the latest issue of BMJ ( British Medical Journal ), Dr Ian Reid and colleagues from the University of Auckland, New zealand, have published their meta-analysis of 11 studies, of 12,000 pateints with at least 4 years followup. They were trying to find out if there is any correlation between calcium supplements and heart disease and strokes. All the studies had one group on calcium and the other on placebo ( not on calcium ). They found that after 4 years of followup, there was a 30% increase incidence of heart attacks in the group taking calcium supplements. Now that is alarming. It is important to note that this is a meta-analysis, and not a randomised, controlled trial.
They did further analysis, and found that for every 1,000 patients on calcium pills, followed for 5 years, there will be 14 more heart attacks, 10 more strokes ( not in the same patients of course ) and 13 more deaths. There were also 26 less fractures, and 37 more adverse reactions. Interesting.
One must always remember that meta-analysis is taking studies which have populations that you would like to study, match them together using your sophisticated computer software, and make them answer questions, for which they were not meant to answer in the original clinical trial. It is very much an after-thought clinical study, with all their inherent shortcomings. The conclusion must not be taken for fact. At best, the conclusions give us an idea of what may be true and generate a hypothesis for us to study further. A meta-analysis is not fact, but should lead to further studies to find out the truth.
Anyway, for whatever good, it would appear that calcium pills are not so harmless and may be related to a higher incidence of heart attacks and strokes.
I for one ( and I am not the only one ), am stump as to how to explain these findings. To the best of my knowledge, I am not aware of calcium being a part of the atherosclerosis process. I also did not know that calcium is a trigger for CVS events. Along the way, the accumulation of calcium ( if the patient's vitamin D levels are good ), in the blood stream could either initiate the artherosclerosis process or act as a trigger for acute CVS events. I know that calcium can trigger arrhythmias.
Anyway, the take home message must be that we should only take pills if they are clinically indicated and not just for fun sake. Even health supplements may not be so innocent afterall. It is no good that in trying to prevent 26 fractures, to cause, 13 deaths, 14 heart attacks and 10 strokes, when using calcium supplements.
There is an alternative to fight post-menopausal osteoporosis, and that is called exercise, fresh air and sunshine. This will also avoid hypertension, obesity and even diabetes.

2 comments:

趙吳維倫彥廷 said...

A bird in hand is worth two in the bush. ............................................................

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