Photo by Walter Ezell, Creative Commons Attribution 3.0 Unported license (1024 x 768)
Moose. Photo by Walter Ezell, Creative Commons Attribution 3.0 Unported license.

The New York Times, known for serious and careful journalism, featured an article on August 17, 2010, that raises a real weighty issue: what causes osteoarthritis (OA) in moose? It instantly became one of the most emailed articles, and that got my attention.  The article quotes a paper published not in a veterinary journal, not even a medical journal, rather in a publication called Ecology Letters.   The authors, Dr. Rolf O. Peterson and Dr. John A.Vucetich are from the Michigan Technological University, department of Forest Resources and Dr.Thomas D. Drummer, department of Mathematical Sciences, as well as Dr. Clark Spencer Larsen of the department of anthropology, Ohio State University.

Now, why would I go to such length in citing the authors’ affiliations? Because it can tell you a lot about the expertise brought to bear on the subject at hand. A field ecologist, a statistician, and an anthropologist? No rheumatologist? Perchance an immunologist? I know, it may sound elitist, but consider this: would you trust an economist, say, to opine on the causes of cancer, or vice versa? Would you trust a biologist whose surgical skills are limited to mice to perform even a simple hernia repair? This has nothing to do with intelligence; I wouldn’t trust a biologist who is a Nobel Prize laureate to perform the surgery.

Admittedly, there are famous cases where an outsider offered a fresh outlook that revolutionized the field. The field oThe New York Times, known for serious and careful journalism, featured an article on August 17, 2010, that raises a real weighty issue: what causes osteoarthritis (OA) in moose? It instantly became one of the most emailed articles, and that got my attention. The article quotes a paper published not in a veterinary journal, not even a medical journal, rather in a publication called Ecology Letters. The authors, Dr. Rolf O. Peterson and Dr. John A.Vucetich are from the Michigan Technological University, Department of Forest Resources and Dr.Thomas D. Drummer, Department of Mathematical Sciences, as well as Dr. Clark Spencer Larsen of the Department of Anthropology, Ohio State University.

Now, why would I go to such length in citing the authors’ affiliations? Because it can tell you a lot about the expertise brought to bear on the subject at hand. A field ecologist, a statistician, and an anthropologist? No rheumatologist? Perchance an immunologist? I know, it may sound elitist, but consider this: would you trust an economist, for example, to opine on the causes of cancer or vice versa? Would you trust a biologist whose surgical skills are limited to mice to perform even a simple hernia repair? This has nothing to do with intelligence; I wouldn’t trust a biologist who is a Nobel Prize laureate to perform the surgery.

Admittedly, there are famous cases where an outsider offered a fresh outlook that revolutionized the field. The field of transplantation immunology made a great leap forward when chemists and molecular biologists entered the field. Likewise, neurobiology advanced rapidly when molecular biologists, physicists, and psychologists became interested. But by and large, lack of intimate knowledge of the field leads to naïve hypotheses.

 

The gist of the paper

The scientists studied the moose population on Isle Royale in Lake Superior. This population established itself on the island about one hundred years ago, feeding on the local balsam fir trees. But this was not a moose’s dream of a private refuge — the wolves living there made sure of that.

What the researchers observed was that out of 1,200 moose they analyzed on the island, more than half had arthritis. It usually attacked the hip and therefore made the moose vulnerable to predator attacks. The arthritic moose were often small, measured by the length of their metatarsal bones in the foot. Small metatarsals indicate poor early nutrition, and scientists determined that the arthritic moose were born during times when food was scarce, so their mothers supposedly could not produce enough milk. This led the authors to speculate that human OA may also be due to early life malnutrition. That has OA) suffered from malnutrition in their childhood strikes me as bit improbable. A plausible alternative explanation for the OA in the moose of Isle Royale is that this geographically isolated population has a high prevalence of genes that make it susceptible to arthritis.

The authors went on to speculate that human OA may also be due to early life malnutrition. But what specific deficiency in the diet could cause OA? The only “evidence” offered to support this hypothesis is that after the Spanish conquistadores arrived in America, the Indians abandoned their hunter–gatherer diet and switched to a corn-based diet that is deficient in two amino acids. This is flimsy evidence, to say the least. Further, to surmise that about 30% of the adult population (the percentage that has OA) suffered from malnutrition in their childhood strikes me as bit improbable.

 

Osteoarthritis in humans

It used to be thought that OA was a “wear and tear” disease. Why did we believe it? Because its incidence increased with age, and because scientists couldn’t find another cause. More recently great strides have been made in understanding the disease. It was observed that biopsies obtained from early OA showed a strong inflammatory component. It is now believed that chronic inflammation is at least partially responsible for this disease. How about the association of obesity and type 2 diabetes with OA? These conditions are also associated with chronic inflammation, so their association with OA is plausible.

 

The science writer’s responsibility

I don’t think this story would have ended up on NYT most emailed list if it was a mildly entertaining story about arthritic moose on an island in Lake Superior, Michigan. The “sexy” part of the story was the nutritional aspect and its possible importance to human OA. For some reason, we tend to ascribe to nutrition anything that we don’t know its cause. Take the gluten intolerance craze. It ihas been implicated in causing childhood autism, ADHD, Crohn’s disease, food intolerance, fatigue syndrome, in addition to being the real cause of celiac disease. Pure balderdash – there is no credible evidence for any of those except celiac disease, which is uncommon.

The problem with such seemingly cute stories is that the public is not equipped to judge the quality of the paper, and the reporter did not help. The suggestion in the paper, as well as in the NYT, that taking a nutritional supplementation starting at pregnancy could actually end up doing harm. A well-meaning, but poorly-informed pregnant woman may take mega-doses of vitamin D to protect her baby from OA. Not only will the drug not benefit her or her unborn child, but hypervitaminosis D can actually have pretty serious consequences. Given the very high quality of the NYT science writers, I would have expected a higher standard before rushing this article to publication.

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.