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Does Vitamin D help alleviate osteoarthritic knee pain? I haven’t the foggiest idea. But neither do the authors of that study or any of the news media that’s done such shoddy reporting on it.

by Heidi Stevenson

Knees, by muffett68

The more Vitamin D is shown to be absolutely essential for health, the more junk science is done to try to show the opposite. The latest is a study purporting to show that Vitamin D doesn’t reduce knee pain or cartilage loss. Naturally, the news media is reporting on the results without any serious consideration of the study’s legitimacy.

The study, “Effect of Vitamin D Supplementation on Progression of Knee Pain and Cartilage Volume Loss in Patients With Symptomatic OsteoarthritisA Randomized Controlled Trial”^[1], is so flawed as to be useless, but you’d never know it from the reports.

Vitamin D is known to be necessary for bone health. The study itself noted that epidemiological studies have shown that people with higher  levels of Vitamin D are less likely to suffer from knee osteoarthritis. Therefore, one must wonder why they did a study that was nearly guaranteed to get the results it did.

The study was randomized, double blind, and placebo controlled. That, of course, is supposed to be the be-all and end-all in modern scientific enquiry. As you’ll see, that claim has little meaning. It claimed to find no benefit in Vitamin D in people who already suffer from advanced osteoarthritis of the knee. So what was wrong? Here’s a list of problems:

• On the 21-point pain scale used by the study, those in the Vitamin D treatment group were worse, at 6.9, compared to those in the placebo group, at 5.8. The treatment group also had worse knee function than the placebo group. It’s well known that differences at the beginning of a study in the groups being compared weaken the study, often to the point of invalidating it.
• The goal was only to bring people’s Vitamin D serum levels up to 36 ng/mL. That level is indicative of deficiency. Unless people are brought to a minimum level of 50 ng/mL or more, no legitimate conclusion can be drawn.
• No consideration was given to Vitamin K2, which acts in concert with Vitamin D, especially for bone and cardiovascular health. No amount of Vitamin D is going to be beneficial if K2 is deficient. This demonstrates how the typical narrow focus of such studies can so easily misrepresent reality.

In other words, the study is junk science, typical pseudo science designed to mislead, not elucidate. Here, though, are some headlines about the study:

• Vitamin D doesn’t help with knee pain: Fox News
• Vitamin D may not relieve arthritis pain: Reuters
• Vitamin D Doesn’t Improve Knee Arthritis, Study Finds: U.S. News & World Report
• Vitamin D may not relieve arthritis pain: Chicago Tribune
• Vitamin D Supplementation Does Not Reduce Knee Pain, Cartilage Loss in Patients With Osteoarthritis: ScienceDaily
• Vitamin D supplementation does not reduce knee pain, cartilage loss in patients with osteoarthritis
• Vitamin D No Help for Arthritic Knees: Medpage Today

It doesn’t matter if the news source is major news media or medical news media. The methods are the same: report the claimed results with little, if any, questioning. They don’t look at the quality of the study. They don’t look for design flaws. They point out the obvious, that the study addresses only fairly advanced cases of osteoarthritis, but that’s not a flaw in the study. It’s merely a limitation. But pointing it out certainly gives the impression that the reporting is balanced. The truth is that the news media just blindly spew out whatever is claimed, and sometimes add a little something to give the impression of being balanced.

Of course, they do this only when the results are favorable for the Big Pharma. The truth? Well, it’s obvious that the truth holds little interest for them.

So, does Vitamin D help alleviate osteoarthritic knee pain? I haven’t the foggiest idea. But neither do the authors of that study or any of the news media that’s done such shoddy reporting on it.

Sources:

1. Effect of Vitamin D Supplementation on Progression of Knee Pain and Cartilage Volume Loss in Patients With Symptomatic OsteoarthritisA Randomized Controlled Trial, JAMA, doi:10.1001/jama.2012.164487.