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Recap of small vitamin D study for heart disease shows fitting restraint

High doses of vitamin D rapidly reduce arterial stiffness

Our Review Summary

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With just a few tweaks, this could have been a stellar release on a small study about the benefits of high doses of vitamin D on arterial stiffness. Arterial stiffness is a cause of atherosclerosis, a  thickening and stiffening of the arterial wall, and is related to high blood pressure or hypertension.

The release presents many of the necessary caveats, avoids disease mongering and unjustifiable language, and does a nice job describing what the researchers did to reach their conclusions. The release also does readers a service by explaining a relatively complex topic in terms that regular readers (and journalists) can understand.

The actual number of people who saw a benefit is missing, though, as is any mention of harms, any mention of other treatments for arterial stiffness, and any mention of how the study was funded or whether there were any conflicts of interest. We gave the release three stars because we felt these were mostly benign omissions. But, in the interest of keeping a high standard for writing strong scientific news releases, we make note of the omissions where they occurred.


Why This Matters

The benefits of daily supplement vitamins are under more scrutiny than ever because of repeated large scale studies that show minimal if any health effects. This raises the bar for researchers wanting to present a persuasive case for the benefits of vitamin D or any other vitamin.


Does the news release adequately discuss the costs of the intervention?


The release responsibly notes that obtaining more vitamin D is a potentially simple endeavor for most individuals. They can drink more milk, for example, or purchase a relatively inexpensive supplement.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The release quantifies the benefits in each group with this statement: “Two thousand IUs decreased stiffness by 2 percent in that timeframe. At 600 IUs, arterial stiffness actually increased slightly – .1 percent – and the placebo group experienced a 2.3 percent increase in arterial stiffness over the timeframe.”

But we’re concerned that the release did not describe any of the statistical testing results. The 2% decrease seen by the group that got 2,000 units per day was not statistically significant. Nor was there a statistical significance in any group that received smaller doses. A difference was only seen in the group that got the highest dose of 4,000 units per day. That distinction was not made clear.

Further, what does a 2% decrease in arterial stiffness mean in terms that would matter to a patient? The 2% decrease in reduced stiffness is a proxy or surrogate marker for a health outcome, but not one that tells us the actual impact on patient health.

On the plus side, the release explains that the study consisted of 70 participants, and that those taking the most vitamin D showed the greatest reduction in arterial stiffness — 10.4 percent in 4 months — but it does not say how many participants that was. The study does make it clear, however. The high-dose group included 18 people.

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

The release does not delve into the side effects of taking high doses of vitamin D over a long period of time. These side effects include kidney stones, which should have been addressed. The study does note, though, that no side effects were reported in the trial.

Does the news release seem to grasp the quality of the evidence?


The release does not make any bold claims about the efficacy of using vitamin D to treat arterial stiffness, but sticks to reporting the facts of the study as they are known. It cites the researchers calling for a larger study:

“Now it’s time to do a larger-scale study, particularly in high-risk populations, and follow participants’ progress for longer periods, Dong and Raed say. “A year would give us even more data and ideas,” Raed adds.”

The researchers essentially say that results are encouraging and the results were published in the journal PLOS ONE. The authors note that the connection between vitamin D and arterial stiffness “might be potential contributors” to heart disease in a certain subset of African Americans.

Does the news release commit disease-mongering?


The release does not hype the dangers of vitamin D deficiency or even heart disease in general, mentioning once and low in the release that heart disease is the leading cause of death in the U.S.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

The release does not mention any particular funding source.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

The release does not discuss any other options patients might have for dealing with arterial stiffness. It does note, however, that there are easy and inexpensive ways to add vitamin D to a person’s diet.

Does the news release establish the availability of the treatment/test/product/procedure?


The release makes clear that it would be simple for almost anyone seeking to increase their vitamin D intake to do so. They can drink more milk, eat more yogurt, eat more greens like kale, take a supplement and so forth.

Does the news release establish the true novelty of the approach?


The release does not overplay its hand here, but does say that the study is “what appears to be the first randomized trial of its kind.” This is a difficult fact to establish but since they are essentially saying, “To the best of our knowledge” this is a first, we’ll give the release the benefit of the doubt here.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?


The tone of the release is carefully measured throughout, with the writer repeatedly using language like “might” and “appears to be.”

Total Score: 6 of 10 Satisfactory


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