This news release suggests that long distance running may be protective of knee cartilage because the amounts of two biomarkers for synovial fluid inflammation decreased after 30 minutes of running. The volunteers in the study were all under 35 and healthy. Similar subjects tested without running showed no decrease in the two markers.
The release does a poor job of conveying the findings and will leave readers with the impression that this research is much more definitive than it really is. Here are a few of the shortcomings:
Patients who suffer joint inflammation are often told to quit running, but if running is beneficial for knee inflammation, then discontinuing this exercise may be unnecessary. This news release makes it sound as if this is the first study to ever address this issue and that the results definitively indicate that running is protective against the development of knee arthritis. But that’s very misleading. In fact, many other studies have looked at this question and come back with conflicting findings. This new study, of only 6 people, is low in quality and adds little to the evidence base. It probably did not deserve a news release at all, no less one that overstates the findings as as carelessly as this one.
There is no cost mentioned, but typically, running does not have any cost requirement except for good shoes. This category is not applicable for this research.
The benefits of this approach are in no way quantified. The news release states that the amounts of inflammation markers decreased, but does not say by how much although the published study includes this information. It should be kept in mind that the inflammation markers are a proxy for what we really care about — actual rates of osteoarthritis. It is doubtful that measuring two biomarkers after a 30-minute run can tell us much about the impact of running over a lifetime.
In addition, the release does not mention that this is a pilot study and that only 11 subjects were used and only 6 actually completed the tests because synovial fluid is difficult to obtain from a healthy joint. The paper does include statistics, but the p values (the probability of obtaining a result equal to or exceeding what was actually observed) may not be of any use when applied to only 6 subjects. This does not seem to be a statistically valid study. The release was probably premature.
Possible harms are not discussed. The release hints that this benefit is there for “healthy” joints, but says nothing about joints with torn cartilage, already degrading joint surfaces or substantial osteoarthritis. The release notes that researchers plan more do more study of those with anterior cruciate ligament (ACL) injuries, but that is a tendon injury, not a joint injury.
There’s a concern that this release could send the wrong message to some runners. What about people who experience pain when they run? Should they continue to run, despite the pain, because running might be “chondroprotective.”
With only 6 successful subjects, the quality of evidence is lousy. But the release doesn’t comment on this at all or discuss any limitations of the study. It doesn’t even tell us how many subjects there were.
The release doesn’t engage in disease mongering. Osteoarthritis in the knees and other joints is a factor of aging. Anything that can prevent this occurrence is of benefit.
There is no funding source listed, but there is also no funding source listed in the paper. The authors do declare in the paper that there is no conflict of interest and what any conflict would be, considering that the “treatment” discussed is running, is a puzzle.
Our standard here is to require some discussion of funding sources. Even if no funding was provided, the release should say so.
There is no mention of any alternatives. Many runners are told to switch to other forms of exercise as they get older to avoid joint pain. Do other forms of exercise produce the same benefits on inflammation?
Obviously, running is available to anyone who’s able to do it for no cost. The release could have pointed out that areas with sidewalks and dedicated trails make this activity more accessible.
As stated in the review summary, many previous studies tried to determine whether running increases the risk of osteoarthritis. But the release doesn’t mention previous research and thus overstates the novelty of the new findings.
People with osteoarthritis are usually advised to continue to exercise. Because running is a high impact aerobic exercise it may sound counter-intuitive to continue running, but not necessarily novel.
The release doesn’t include unjustifiable, sensational language. However, the focus on a study with functionally only 6 subjects isn’t at all as revealing as the headline suggests.
It reads: “Running may also slow the process that leads to osteoarthritis.” That’s confusing. Besides slowing the process, what does running do?