Study: Gulf War ALS Peaked '96, Then Declined
 

Study: Gulf War ALS Peaked '96, Then Declined
U.S. veterans of the first Gulf War don’t have a permanently increased chance of developing ALS (amyotrophic lateral sclerosis, or Lou Gehrig’s disease), according to a new study supported by the Department of Veterans Affairs and the Department of Defense and published online June 6 in Neuroepidemiology.

“Basically, the outbreak has run its course,” said Ronnie Horner, a professor at the Institute for the Study of Health at the University of Cincinnati and an author on the study. “The excess risk appears to have dissipated.”

Horner, with colleagues at other universities and at Veterans Affairs Medical Centers, compared the incidence of new ALS cases that occurred between 1991 and 2001 in two groups: 700,000 military personnel deployed to the Persian Gulf region in 1990-1991, in whom 48 cases occurred; and 1.8 million people who were in the military during that period but weren’t sent to the Gulf, in whom 76 cases occurred.

They found those who didn’t go to the Persian Gulf region in 1990-1991 had a low incidence of ALS compared to the average risk for men in western Washington state during this entire period; but that those who served in the Gulf region showed a consistently higher incidence of ALS compared to average Washington state men and to the non-Gulf-deployed military population during some of those years.

The incidence of new ALS cases steadily increased among Gulf-deployed personnel between 1994 and 1996, about four to six years after deployment, peaking in 1996, after which it declined. By 2001, their risk was the same as for the nondeployed military personnel and below the risk for the male Washington state population in general.

The data suggest there were specific exposures or other events associated with the first Gulf War that, perhaps in combination with genetic susceptibility factors, led to a temporary rise in ALS cases.

“We have to keep a very open and creative mind here,” Horner said. “It may not be any single exposure or single factor. It may be multiple exposures to multiple agents. Moreover, it may be not only that it was multiple exposures but multiple exposures over a brief period of time, leading to an exposure that was above the threshold needed to trigger onset. Genetic proclivity may be involved as well. However, this is all speculation, as we do not currently know enough to say what caused the outbreak.”

Critics of the findings have charged that veterans who were in the Persian Gulf should have been compared only to the general population and not to nondeployed veterans; and that the study may have undercounted ALS cases in nondeployed veterans and/or overcounted them in deployed veterans.

Horner disputes both claims. His team hypothesized that those who served in the Gulf region in 1990-1991 might have incurred an elevated ALS risk compared to a matched occupational group that didn’t serve in that region, which he believes is a valid study design. “The nondeployed were likely similar in most characteristics to the deployed,” he said, “but we can’t say for sure. All would be more physically fit than the general population.”

He also believes ALS cases in both groups were accurately counted. “We used the same methods to identify ALS cases in the deployed and nondeployed,” he said. “Most cases were identified through multiple sources.”

Horner also noted, “If we can identify the cause of the outbreak among Gulf War veterans, we may also gain clues as to the etiology of ALS in the general population. Once we understand the cause, we can begin to develop ways to intervene to either prevent or disrupt the disease.”


http://www.als-mda.org/research/news..._gulf_war.html