Studies Suggest Military Service Increases Risk for ALS
11.10.06, 12:00 AM ET
ALS is a rare but fatal neurodegenerative disease. The report, from the U.S. Institute of Medicine, concludes that further research is needed to confirm a connection, since there are only five studies so far on the relationship between military service and the disease.
"The connection is pretty strong statistically," said Dr. Richard T. Johnson, chairman of the committee that wrote the report and Distinguished Service Professor of Neurology at Johns Hopkins University's School of Medicine. "But the risk [of developing ALS] is small," he added. "It's only a 50 percent increase in risk."
Of the five studies, three that were done among Gulf War veterans found that the chance of veterans developing ALS was two times higher than for the general population, or for veterans who weren't in that 1990-1991 war.
A fourth study found that military service before the Gulf War was associated with a 1.5-fold increased risk of developing ALS.
But, the fifth study did not find an association between military service and ALS.
About 0.01 percent of the U.S. population, some 20,000 to 30,000 people, develop ALS. Those with the disease experience a progressive breakdown of nerve cells that control the muscles, eventually resulting in paralysis and death.
Johnson thinks that, while the connection is statistically significant, the study findings need to be replicated. "The question is, if it's true, then why does military service increase your risk?"
To pin down the connection, the report calls for more high-quality studies on the relationship between military service and ALS. Research also should examine what might be causing ALS among veterans. It's not known whether the risk is from exposure to toxic chemicals, involvement in traumatic events, intensive physical activity, or other experiences soldiers encounter, the researchers said.
Johnson doesn't think veterans should be overly concerned about their risk for ALS. "The risk is so small that's it's not something that one worries about," he said.
One expert thinks the connection between ALS and military service needs more exploration.
"This was important to review and was not unexpected to me in terms of findings," said Lucie Bruijn, the science director of the ALS Association. "Although there is limited evidence, it is very suggestive, and I think that the recommendations for further studies are very important."
Genetics account for 5 percent to 10 percent of the risk for ALS, Bruijn said. "Ninety percent of ALS is sporadic. So there is no real known cause," she said.
Bruijn does think, however, that there are environmental conditions that can trigger genetic susceptibility. "We all believe, in the scientific community, it's the combination of the environment and genes. In this instance [among the military], the same is going on," she said. "There is genetic susceptibility plus environmental exposure that puts them in this position."
Currently, veterans of the Gulf War get disability compensation from the U.S. Department of Veterans Affairs if they develop ALS, but other veterans do not.
"Congress needs to continue to fund research in this area," said Steve Gibson, the ALS Association's vice president for government relations. "We think that because of this connection, it is imperative that we protect our men and women. Because right now, if you fight for our country, you are at higher risk of developing ALS, and we need to find out the reasons why."
More information
To learn more, visit the ALS Association.