Ride For Life: ALS linked to sports, slimness

Researchers at Columbia University and Columbia-Presbyterian Medical Center have found people who have amyotrophic lateral sclerosis, sometimes called Lou Gehrig's Disease, are more likely to have always had slim bodies or participated heavily in athletics.

"People with ALS were twice as likely to have been slim and this might indicate that there seems to be an association between slimness and ALS," Nikolaos Scarmeas, lead author of the research, told United Press International.

"But it's too far a stretch to say that if you are slim you have that much more chance of developing the disease," said Scarmeas an assistant professor of neurology at Columbia. In order to draw that conclusion, he added, a different type of study would have to be designed. In ALS, the nerves controlling the voluntary muscles deteriorate. The disease usually progresses rapidly and is always fatal.

The Columbia study included 431 subjects, of whom 279 had ALS and 152 suffered from other neurological disorders. Participants were asked if they always had been slim and whether or not they had participated in varsity athletics in high school or at any point in their lives. The subjects also estimated their height and weight prior to developing disease.

Based on the responses, the researchers found people who had ALS were 2.2 times as likely to have always been slim and 1.7 times as likely to have been heavily involved in varsity sports. Other studies have obtain different results, Scarmeas said, but he pointed out those studies used smaller patient populations.

Lucie Bruijn, a neurobiologist who is science director and vice-president of the ALS Association in Calabasas, Calif., told UPI this area of research always has been somewhat controversial.

"That's partly because these studies are very difficult to do. It's data collection. It's reporting from patients," Bruijn said. "Thousands and thousands of slim athletes never develop ALS. Clearly to not do athletics or to not be slim is not the answer ... It's more complicated than just thinking about the disease and athletics."

Scarmeas and colleagues mentioned several theoretical mechanisms by which the body type and athletics associations may arise. For example, vigorous physical activity might increase exposure to environmental toxins or facilitate the transport of toxins in the blood to the brain or motor controlling nerves.

Also, slimness might be an early manifestation of motor neuron disease, or MND -- another name for ALS -- they said.

Catherine Lomen-Hoerth, an assistant professor of neurology at University of California at San Francisco and associate director of the UCSF ALS center, said experiments with mice genetically predisposed to ALS might be able to confirm that environmental toxins such as pesticides are a contributing factor, perhaps in combination with genetic predisposition.

Regarding the concerns about exercising expressed by the researchers and other experts, Lomen-Hoerth told UPI, "It's critical to continue to exercise and not fear that exercising would necessarily increase the risk of ALS. Heart disease and stroke are much more common and exercise helps to prevent those diseases."

According to the International Alliance of ALS/MND Associations, 120,000 new cases of ALS are diagnosed worldwide each year. The U.S. National Institutes of Health report about 20,000 Americans have ALS.

The research is published in the Sept. 10 issue of the journal Neurology.