New vitamin D trials have 'little chance' of showing health benefits, warns analysis

11-Feb-2014 - Last updated on 13-Feb-2014 at 08:08 GMT

Randomised controlled trials on supplementation with vitamin D seem to show that the vitamin has little causal effect on our health outcomes, according to a new meta-analysis which suggests that future research is 'unlikely' to alter such conclusions.

The study, published in The Lancet Diabetes & Endocrinology, examined the existing evidence from 40 randomised controlled trials - concluding that vitamin D supplementation does not prevent heart attack, stroke, cancer, or bone fractures in the general population by more than 15%.

Led by Dr Mark Bolland from the University of Auckland, New Zealand, the team behind the new analysis added that as a result vitamin D supplements probably provide little, if any, health benefit - and that future randomised trials with similar designs are 'unlikely' to reveal conclusions any different to those already published.

"Findings from observational studies have shown vitamin D insufficiency to be associated with a wide variety of disorders such as fractures, ischaemic heart disease, cerebrovascular disease, and cancer," noted Bolland and his team. "Such findings have led to calls for widespread vitamin D supplementation. However, some researchers have suggested that such recommendations should not be made without supportive trial data, and they have therefore called for randomised controlled trials of vitamin D supplementation with non-skeletal endpoints as primary outcomes."

Bolland and his colleagues used this trial data to perform several types of meta-analysis including a 'futility analysis', which predicts the potential of future study results to sway existing evidence - the results of which indicate that the effect of vitamin D, taken with or without calcium, on heart attack, stroke, cancer, and total fracture lies below a 'futility threshold'.

"In view of our findings, there is little justification for prescribing vitamin D supplements to prevent myocardial infarction or ischaemic heart disease, stroke or cerebrovascular disease, cancer, or fractures, or to reduce the risk of death in unselected community-dwelling individuals. Investigators and funding bodies should consider the probable futility of undertaking similar trials of vitamin D to investigate any of these endpoints," said the team.

9 comments

Lancet is Biased by Drug Companies

Posted by William Bowers, 14 February 2014 - 15:56 GMT

First,the do not discuss the difference between synthetic and Whole Foods..
Investigate for yourselves.Physicians rely on testing and funding thru drug companies.
The bulk of Doctors education is thru these same Big Pharma Groups.

Trust more in the Dr.Andrew Weil's and Dr. Mehmet Oz's who have no dog in the fight.
Drug Companies bottom line is being crushed by an understanding of Whole Foods.
Synthetics are toxic to the body.It was a 1960's ruling by Estes Kefauver making synthetic supplements the standard for testing in the U.S.

We are what we eat,food not chemicals.
Respectfully,
William J.Bowers

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methodological issues

Posted by JA Larson, 12 February 2014 - 20:48 GMT

The choice of D2 or D3 affects results.

http://ajcn.nutrition.org/content/84/4/694.full

http://summaries.cochrane.org/CD007470/vitamin-d-supplementation-for-prevention-of-mortality-in-adults

The choice of dosing intervals affects results.

The Role of the Parent Compound Vitamin D with
Respect to Metabolism and Function: Why Clinical
Dose Intervals can affect Clinical Outcomes
Bruce W. Hollis, PhD, and Carol L. Wagner, MD
doi: 10.1210/jc.2013-2653 J Clin Endocrinol Metab jcem.endojournals.org

The choice of outcomes and sample population affects results.

In one study, they gave D to elderly hospitalized COPD patients (some of whom were still smoking). Really? They expect a Lazarus Effect?

Finally most studies give a standard dose to everybody.

So a 80 pound woman needs the same amount of D as a 250 pound man? A person with a serum level of 5 ng/ml needs the same amount of D as someone with a serum level of 40 ng/ml?

Giving a dose to a population with a bell curve serum distribution results in a new bell curve.

Effect of oral cholecalciferol 2,000 versus 5,000 IU on serum vitamin D, PTH, bone and muscle strength in patients with vitamin D deficiency
Osteoporosis International, 02/19/2013, Diamond T et al

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Vitamin D3 Study

Posted by Telekinetic, 12 February 2014 - 20:35 GMT

To Laszlo G Meszaros:

I find the results of your Vitamin D3 study to corroborate what others have found and that the authors of this article have missed- deliberately or not. It is critical that the supplementation of Vitamin D3 be accompanied with a Vitamin K2 complex, which deposits freely circulating calcium in the bloodstream to be deposited on bone rather than on arterial walls, which is one of the causes of arterial rigidity.

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