Back to the Future
One of my favorite Woody Allen movies dates back to 1973. Sleeper tells the tale of one Miles Monroe, a Greenwich Village health food store owner who, after a minor operation goes awry, is “cryogenically-preserved” (i.e., frozen), to be “thawed-out” later when medical science has a cure.
Some 200 years in the future, Miles’ form is warmed by a group of underground anti-police state revolutionaries who want to use him for their cause (he has no government ID). While questioning him about 20th century life, two doctors have the following conversation about the items Miles used to sell in his store:
Dr. Melik… wheat germ, organic honey and… tiger’s milk.
Dr. Aragon: Oh, yes. Those are the charmed substances that some years ago were thought to contain life-preserving properties.
Dr. Melik: You mean there was no deep fat? No steak or cream pies or… hot fudge?
Dr. Aragon: [chuckling] Those were thought to be unhealthy… precisely the opposite of what we now know to be true.
Dr. Melik: Incredible!
Media headlines over the past couple of weeks have reminded me of this scene, as they have breathlessly reported the latest results from some pretty impressive (in terms of size and scope at least) studies. According to print and electronic “summaries” of these studies, we now “know” that:
- Following an eating pattern lower in total fat does not significantly reduce the incidence of breast cancer, heart disease, or stroke, and does not reduce the risk of colorectal cancer in healthy postmenopausal women, according to the latest clinical trial results from the National Institutes of Health’s Women’s Health Initiative (WHI).
- Calcium and vitamin D supplements in healthy postmenopausal women provide a modest benefit in preserving bone mass and prevent hip fractures in certain groups including older women but do not prevent other types of fractures or colorectal cancer, according to the results of a major clinical trial, part of the Women’s Health Initiative (WHI). While generally well tolerated, the supplements were associated with an increased risk of kidney stones.
- There is no overall benefit in the use of the popular dietary supplements glucosamine and chondroitin sulfate for people with arthritis. Subjects who took a placebo had just as much relief from pain as those who took the supplements, according to a study published in the New England Journal of Medicine.
All of the above are representations of media accounts of these studies. Now, a few years ago in this space (Article #60), I ranted a bit on this topic of media coverage of medical studies. And, as I noted then, a closer look at the methods and results of these studies reveals a more complex and intricate picture than is implied in the media-reported conclusions. Space limitations prohibit an in-depth look at the flaws with, and misconceptions about, all of these investigations, but I will comment on the study on arthritis supplements, which I imagine would be of most interest to runners.
A careful review of the published study itself (N Engl J Med 2006;354:795-808) reveals several important points that justify a certain level of caution before one would consider dismissing the potential benefit of these supplements in treating arthritis pain. In fact, the authors themselves outline some of the limitations of the study:
- First, the high rate of response to placebo (60.1%) and the relatively mild degree of pain from osteoarthritis among the participants may have limited our ability to detect benefits of the treatments.
- In addition, our patients had relatively mild knee pain at baseline, as compared with that in classic studies of osteoarthritis, in which a criterion for entry was a disease flare after the discontinuation of NSAIDs.
- Treatment effects were more substantial in the subgroup of patients with moderate-to-severe pain, but the relatively small numbers of patients in this subgroup may have limited the study’s power to demonstrate significant benefits in the glucosamine, chondroitin sulfate, and celecoxib groups.
In other words, there are some serious questions about the design of the study in terms of the type of patient chosen to participate. Those with more severe arthritis may very well obtain some benefit from taking the supplements, or at least would be more likely to show measurable differences, compared with those who have only mild levels of pain to begin with, but we don’t know for sure because so few of the subjects fell into the former category.
I am not trying to make a case here for the use of glucosamine and/or chondroitin sulfate (I think the jury is still out on this one). Rather, I’m only advocating a more discerning look at media reports on medical studies prior to drawing conclusions on what actions, if any, you should take. Before you make any radical changes in diet, medication, supplements, or exercise routine, it might be a good idea to speak with your doctor or other healthcare provider. After all, you don’t want to feel silly 200 years from now when everything we “know” now has changed.