Sept. 9, 2002 -- Ever since the career of baseball great Lou Gehrig was cut short by ALS, the disease has been forever linked to elite athletes. But a new study suggests that slim, athletic individuals may actually be more likely to develop diseases that gradually erode muscle strength, such as ALS.
Diseases that affect the nerves that control muscles -- including ALS -- are called motor neuron diseases. Researchers found that people who had always been slim were more than twice as likely to develop motor neuron diseases than those who were heavier. And varsity athletes were 1.7 times more likely to develop these diseases later in life.
For the study, researchers compared 279 people with motor neuron disease to a similar group of 152 people with other diseases that affect the brain and nervous system. The results appear in the September issue of Neurology.
According to the CDC, only about 14% of the general population participated in physical activities and even fewer reach the level of varsity athletics. But the study authors found 38% of their patients with motor neuron diseases had been varsity athletes, compared with 27% of the comparison group.
Researchers say they aren't sure why there's a higher concentration of motor neuron disease among top athletes. But they suggest that vigorous physical activity might somehow increase exposure to environmental toxins or make it easier for the brain and body to absorb these toxins. Another possible explanation may be that the added physical stress of being an elite athlete might make them more susceptible to disease.
However, the study authors caution that these results are only preliminary and should not in any way discourage people from participating in sports.
"Thousands and thousands of slim athletes never develop ALS. Why a tiny few of them do develop ALS is still unknown," according to study researcher Nikolaos Scarmeas, MD, of Columbia University, and colleagues. "There is certainly no justification to avoid athletics in attempts to avoid motor neuron diseases."
In addition, the researchers say there is nothing in their study to suggest that people with ALS should not exercise or be as well nourished as possible.