Amyotrophic lateral sclerosis has been all over social media lately with the all familiar ice bucket challenge. The attention A.L.S. is getting from the challenge has raised the debate of whether or not contact sports of vigorous exercise might somehow contribute to the development of the fatal disease.
Ever since the Yankees first baseman Lou Gehrig died of A.L.S. in 1941, many Americans have been worried about the connection between A.L.S. and sports. In past decades, several studies suggested that professional Italian soccer players were more prone to developing A.L.S. than the normal population.
A recent study conducted on patients in Europe found weak but measurable associations between playing contact sports and a heightened risk for A.L.S. But these studies were extremely small, so to determine what role sports and exercise play in the risk for A.L.S., researchers from across Europe recently combined their efforts into two major new studies.
The most impressive study, published in May in Annals of Neurology, involved almost two dozen researchers from five nations, and 625 A.L.S. patients. The patients were asked if they would be willing to discuss their activities and lives. The researchers did the same with 1,166 people of matching ages, genders, and nationalities who did not have the disease. The researchers conducted extensive interviews with the groups, asking each individual how active they had been in professional or amateur sports, at their jobs and during leisure times. They also asked about past histories of injuries and accidents, including concussions and other head trauma.
The results reassure those of us who do exercise. The numbers showed that physical activity did not increase the risk of developing A.L.S. Instead, exercise actually appeared to offer some protection against the disease.
However, the researcher did find that a history of multiple hits to the head did significantly increase their risk of developing A.L.S. Men and women who sustained at least two concussions or other serious head injuries were much more likely to develop A.L.S. than individuals who have never experienced a concussion or severe blow to the head.
In the U.S., a few researchers have begun to look at football and A.L.S., given evidence that head trauma sustained playing football might contribute to neurodegenerative diseases. But to date, the football data has been inconclusive.