A government-supported research team announced in the Sept. 23 issue of the journal Neurology that having served in southwest Asia during the Gulf War significantly increases the risk of later developing ALS.
Veterans of the Gulf War were found to be about twice as likely to develop ALS as were military personnel who didn’t go to the gulf during the same period. (This finding was released as a preliminary announcement late in 2001. The results are now fully analyzed and "official.")
Among the study’s authors were Hiroshi Mitsumoto, director of the Eleanor and Lou Gehrig MDA/ALS Research Center in New York, and Yadollah Harati, a neuromuscular disease specialist at the Vicki Appel Neuromuscular Clinic at Baylor College of Medicine in Houston. MDA also helped to identify people who served in the Persian Gulf War and later developed ALS.
Air Force risk slightly higher
The investigators compared U.S. military personnel who were deployed to southwest Asia (Saudi Arabia, Kuwait and the other Arab emirates, Turkey, the Indian Ocean island Diego Garcia, or on the Red Sea) for at least one month between Aug. 2, 1990, and July 31, 1991, with military personnel not deployed to this area during the same period, when the Gulf War was fought.
Among the 1.8 million troops not sent to southwest Asia during the targeted period, there were 67 cases of ALS. Among the 700,000 sent to southwest Asia, there were 40 subsequent cases of ALS.
Although the overall number of ALS cases was small in both groups, the researchers determined that the risk of developing ALS for personnel deployed to southwest Asia was, for all service branches, almost twice (1.92 times) that of the risk for the nondeployed personnel.
The risk of developing postwar ALS was highest in those who served in the Air Force (2.68 times the risk for nondeployed personnel) and the Army (2.04 times). Elevated risks found for deployed Navy, Marine Corps, and Reserves/National Guard personnel didn’t reach statistical significance, the investigators say.
Environmental factors involved
The study authors note that clues to possible risk factors that may account for the greater than expected number of ALS cases may come from analyzing interviews of the veterans and comparing interview data with possible environmental risk factors associated with the Gulf War.
The U.S. Department of Defense and Department of Veterans Affairs supported the research.
"To me, this study caused a renewed interest in the environmental factors in ALS," Mitsumoto said. "I strongly believe that a rekindling of ALS epidemiology [the study of disease patterns] is the most important spin-off of this Gulf War study. We must pay more attention to genetic and environmental interaction as a cause of this dreaded disease."
MDA is now considering involvement with a large-scale study of ALS epidemiology in the United States.
Two studies agree
A second study of ALS development in Gulf War veterans was conducted by epidemiologist Robert Haley of the University of Texas Southwestern Medical Center in Dallas. Haley found 20 cases of ALS, 17 of which were diagnosed in subjects under
He found that the number of new ALS cases observed in veterans during the first four years after the war — 1991 through 1994 — was about the same as the expected number for males of the same age. However, over the next four years, the observed incidence of ALS in the Gulf War veterans was about twice the expected number. The highest incidence occurred in 1998, the last year of his study, when new ALS cases were three times the expected number among the vets.
Harati says the two studies support each other and that together they suggest a real difference in ALS incidence in Gulf War veterans compared to others.
He admits that he and many other neurologists were initially skeptical of veterans’ claims of an excess occurrence of ALS following the Gulf War, but he says the study results have changed his mind.
Harati notes that Haley’s study was conducted with the support of the [Ross] Perot Foundation, which "hoped" to find an increase in ALS cases, while the federal agencies behind the government study had probably hoped not to find one.
"Then, lo and behold," he says, "they were in agreement."
The agreement between the two studies, he says, "is a strong statement."
Questions about cause
When it comes to the biological implications of the two studies, Harati is uncertain.
"My feeling is that the stress of war itself, or the stress of the training in the military, or the makeup of these individuals — the fact that certain people are being selected for service — could all be factors, but that is the purest speculation."
As to whether U.S. troops now in Iraq are facing an increased risk of developing ALS, Harati was also uncertain.
"If you say that the stress of war somehow contributes to it, yes, they’re in the same position. But if you say the Gulf War findings had something to do with toxins, with fumes from burning oil, with depleted uranium, then these are probably not happening this time."
Veterans of the Gulf War who develop ALS are eligible for service-connected benefits from the Veterans Administration. For more information about this, go to www.va.gov/health_benefits or call (877) 222-VETS.