One more knock against Vitamin D

Study adds to evidence that supplementation does not prevent falls in the elderly

Photo: Vitamin D

Photo: Jimmy Anderson/iStockPhoto


Are vitamin D supplements magic pills, or simply a waste of money? Despite hope from a few scientific papers, a new study published today in The Lancet Diabetes and Endocrinology adds to the evidence that supplemental Vitamin D does not prevent falls in elderly patients.

For an average patient, deciphering medical research about Vitamin D can feel nearly impossible. One day it’s touted in the media as a panacea: helping with everything from bad cholesterol (http://www.startribune.com/lifestyle/health/253054451.html) to cavities in toddlers (http://www.reuters.com/article/2014/04/21/us-low-vitamin-toddlers-idUSBREA3K0X820140421) – but the next day yet another study comes out saying that it doesn’t live up to the hype (http://blogs.discovermagazine.com/d-brief/2014/04/01/d-bunked-vitamin-ds-benefits-are-overhyped-study-says/)

Amidst this confusion is a debate about whether vitamin D can help prevent falls in elderly people.

Doctors have long hoped that vitamin D might improve muscle function, leading to fewer falls. But today’s study from University of Auckland, New Zealand adds to a growing body of literature suggesting that the evidence doesn’t back up this claim.

For the study, researchers did a meta analysis– pooling data from 20 randomized clinical trials that included almost 30,000 test subjects. They found that vitamin D supplementation- with or without the addition of calcium- had no effect on falls.

Furthermore, the researchers did a statistical analysis that showed that further research was unlikely to change these findings. “We can be very confident that vitamin D supplements do not reduce falls by 15%, and that doing future trials that are similar to the current trials is very unlikely to change that conclusion,” says study author Dr. Mark Bolland.

So does that shut the door on this issue? Not necessarily, says, Dr. Clifford Rosen- who co-authored a comment that was published along with the study. He explained that it would take a very, very large study to conclusively prove that vitamin D actually had an effect on falls. For now, the evidence simply isn’t there. “This study illustrates that we don’t have enough convincing data that vitamin D is an intervention that should be applied globally to prevent falls,” explains Rosen.

“We know that older, frailer people with other illnesses are likely to have both lower vitamin D levels and higher risk of falls Our analyses show that raising vitamin D levels with vitamin D supplements does not prevent falls. This suggests that low vitamin D levels are a marker of frailty and high risk of falls rather than a cause of falls,” says study author Professor Mark Bolland.

This echoes previous findings that show that low vitamin D levels are correlated with everything from cancer to heart disease (http://well.blogs.nytimes.com/2014/04/01/low-vitamin-d-levels-linked-to-disease-in-two-big-studies/?_php=true&_type=blogs&_r=0 ). As with the evidence surrounding frail elderly patients with low levels of vitamin D, these findings are easily misinterpreted. What they do demonstrate is that people who have low levels of vitamin D have a higher risk of death from cancer and heart disease.What they don’t demonstrate, however, is whether these low levels cause these issues or whether supplementing vitamin D would lead to better outcomes. Indeed, vitamin D may simply be a marker of good health. “if you think you know a little about medicine and you see that your risk of cancer, heart disease, death is higher if your levels are low– why wouldn’t you take vitamin D? The danger is not looking critically at the evidence.” Obese people tend to have lower levels of vitamin D, says Rosen, and they also have a higher risk of death from heart disease.

But lack of evidence is hardly a deterrent for many people – including doctors. “Everybody is prescribing it,” says Rosen, “it’s universal. Talk to primary care doctors- everybody gives vitamin D because it’s so benign…If you ask the doctors why- they say take it just in case it’s shown later on that it has a benefit.”

Rosen understands why many people want to continue to believe in the power of vitamin D. And he says that there is one group who would benefit from taking supplements- those at risk for osteomalacia, or defective bone mineralization. Clinical risk factors for this issue include frailty, dark skin, lack of sun exposure and low vitamin D levels. Furthermore, because of the way the data in most trials are collected- today’s study could not address whether vitamin D might be more helpful in elderly people who falls repeatedly.

But overall, says Rosen, the medical literature simply doesn’t support the use of vitamin D supplements in people who are not at risk of osteomalacia. “The evidence simply isn’t there.” But despite the data, he doubts that people will give up on their vitamin D quite yet. “I may be the only person in the world not taking it,” he joked.

Hayley Goldbach, MD
2013-2014 Stanford-NBC News Global Health and Media Fellow

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About Hayley Goldbach

Hayley Goldbach, 2013-2014 Stanford-NBC News Global Health and Media Fellow