Gulf War Link to Lou Gehrig's Disease Bolstered

Studies say the incidence of fatal disease is twice as high in soldiers

MONDAY, Sept. 22, 2003 (HealthDayNews) -- Data that convinced the U.S. government to approve full benefits for Gulf War veterans with Lou Gehrig's disease two years ago has now been published in a peer-reviewed journal.

That study appears in the Sept. 23 issue of Neurology, along with a second study that found startlingly similar results: Veterans of Desert Storm and Desert Shield in 1991 have about double the rate of this fatal neurodegenerative disease.

An accompanying editorial, however, raises a number of questions about the findings.

Also known as ALS (amyotrophic lateral sclerosis), Lou Gehrig's disease is a neurodegenerative disorder that affects nerve cells in the brain and spinal cord. Death usually occurs within five years after diagnosis. The disease affects about 30,000 Americans, almost all of them between the ages of 50 and 70. ALS rarely affects anyone below the age of 45, even though its namesake, the legendary first baseman for the New York Yankees, was just shy of his 38th birthday when he died.

There has been speculation that military personnel who served in the Gulf War suffer a higher incidence of ALS, but studies on the subject have not been conclusive.

In 2001, Veterans Affairs Secretary Anthony Principi announced the government would extend full medical benefits to Gulf soldiers afflicted with the disease. The move was considered an about-face for the government, which up to that point had denied any link.

The first study, appearing in the Sept. 23 issue of Neurology, tried to identify all cases of ALS among military personnel after the start of the war. Out of about 2.5 million military personnel, researchers identified 107 cases of ALS, 40 of them in deployed individuals and 67 in non-deployed. At the time, the number of deployed personnel was less than half that of non-deployed personnel.

"The overall risk of developing Lou Gehrig's for those actually deployed to the Persian Gulf theater of war are approximately twofold greater than you would find among those who were not deployed," explains Ronnie Horner, lead author of the study, which was conducted while he was director of the VA Epidemiologic Research and Information Center in Durham, N.C. The level of risk among those who were not deployed was very near that of the general population.

Within the different service branches, the highest risk was found in the Air Force, followed by the Army, Navy and the Marines.

The second study looked specifically at ALS cases in younger veterans and found the rates of ALS in this segment of the population were more than double those in the general population. During the eight years following the conclusion of the war, 20 cases of ALS were confirmed in about 690,000 Gulf War veterans, with 17 of them diagnosed in people under the age of 45. These figures were thought to represent less than half the actual number.

The editorial writer, however, says the number of people involved is just too small to draw firm conclusions. "The calculated risk may easily be changed either way if the methodology has any flaws," says Dr. Michael Rose of King's College Hospital in London.

The study authors are used to such skepticism, both from within and outside the scientific community. According to Horner, some of the peer reviewers for Neurology said they didn't believe the findings but the editor decided to publish the information anyway and let the scientific community decide for itself.

Small clusters of disease are frequently met with skepticism from neurologists, says Dr. Robert W. Haley, author of the second study and chief of epidemiology at the University of Texas Southwestern Medical Center in Dallas. "Neurologists are very sensitized to not over-interpreting a cluster," he says. "It took me four years to get my papers published."

But now, Haley adds, "the controversy is no longer scientifically defensible. Different groups who had nothing to do with each other did the two studies here. We used entirely different methods and got basically the same answer, that there is a significantly higher rate of ALS in Gulf War veterans, period."

The final paragraph of the editorial implies the current information is not going to be of any use in determining a trigger or cause. Both study authors take exception to that point of view.

"It's terribly tragic but from a scientific view, when you get clusters of a disease that normally occurs sporadically it often gives you a golden opportunity to find a cause," Haley says.

In the general population, about 10 percent of ALS cases involve a family history, the other 90 percent don't have a known cause. Scientists have hypothesized the Gulf War cluster might be related to exposure to a nerve gas, but that is far from confirmed.

Haley is exploring the possibility that the nerve gas sarin may have triggered the disease in genetically susceptible individuals.

"If there's a higher incidence in a certain group then the next logical question and where the payoff comes is in trying to understand how and why," says Mary Lyon, vice president of patient services at the ALS Association.

More information

For more on Lou Gehrig's disease, try the ALS Association or the Muscular Dystrophy Association.

To find out more about Gulf War syndrome, try GulfLink, from the Office of the Special Assistant for Gulf War Illnesses.

Any Gulf War veterans diagnosed with ALS who are interested in participating in further research with Haley should call 214-648-3075. The study is not open to veterans of other conflicts.

SOURCES: Robert W. Haley, M.D., professor, internal medicine, and chief, epidemiology, University of Texas Southwestern Medical Center, Dallas; Ronnie Horner, Ph.D., program director, health disparities, National Institute of Neurological Disorders and Stroke, Bethesda, Md.; Mary Lyon, R.N., vice president, patient services, ALS Association, Calabasas Hills, Calif.; Sept. 23, 2003, Neurology
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