nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
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Friday, July 30, 2010

Another Blow To The Supplement Industry. Study: Calcium Supplements Harmful

 
This is for all of you who are eating crushed oyster shells every day.

According to BBC News (July 29), the study, in the British Medical Journal, said
"people who took supplements were 30% more likely to have a heart attack.  Data from 11 trials also suggested the medicines were not very effective at preventing bone fractures.  Almost 3m people in the UK are thought to have osteoporosis and many take calcium pills to prevent fractures.
In all 12,000 people aged over 40 took part in the trials of calcium supplements of 500mg or more a day.  The risk of heart attack was seen across men and women, was independent of age and the type of supplement given.  A small increased risk of death was seen in the study but was not statistically significant, the researchers said.  The reason for the increased risk of heart attack is not clear but it is thought the extra calcium circulating in the blood could lead to a hardening of the arteries."
Some doctors recommend calcium supplements for those who are risk for osteoporosis.  Others believe that a balanced diet and adequate Vitamin D from exposure to sunshine is all you need for prevention.  Note that the difference is the question or risk.  If you have a strong family history of osteoporosis, then calcium supplements and medications can be used...one or the other or both.
 
But there are two reasons to be cautious about this research:
1.  Note that the risk of heart attack was increased but the risk of death was not statistically significant.  This means they need to go back and see why the first effect (MI) didn't impact the second (death).  In some cases, it could be a confounding factor in the experimental design, in others it could be that there actually is an increased risk of death, but it's covered up by the mass of other causes.
2.  Percent increases in anything need to be looked at closely.  For instance it some bad result occurs at a baseline rate of 3 in a million, and adding a new variable (like calcium) increased the rate to 4 in a million, that's a 33% increase.  But it's not particularly noteworthy.  (Note:  this is an extreme example, to make a point.  The data in the study was 111 MI's increasing to 143 with Ca)
 
In any case, common sense says to talk to your doctor.  There's a place for using calcium supplements; and a place for not using them.
 
Doc D
 
 
 

2 comments:

WarmSocks said...

Is this the meta-analysis referenced in an article on MedPage Today? They threw out all the data where vitamin D accompanied the calcium. Some of the studies had missing/incomplete data. These weren't blind studies. Nothing at all was said about cal/mag, which is often the recommendation for calcium supplementation. The results didn't sound exactly conclusive.

Thank you for posting research results!

Doc D said...

It's the same. You noticed that the confidence interval bordered on 1.0 at the low end, and odds ratio averaged ~1.3, which is not a huge effect. I think they came to essentially the same conclusion: each patient's situation needs to be examined in detail and decision to supplement or not made accordingly.

They just said it better than I did...

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