The diverse group of physical complaints known as "Gulf War Syndrome" may be six distinct patterns of symptoms, some of which appear associated with specific combinations of chemical exposures soldiers may have encountered during the Persian Gulf War, a group of researchers said yesterday.
In addition, the researchers found that a small sample of chronically ill gulf veterans had subtle, though wide-ranging, abnormalities on tests of nerve and brain function compared with soldiers who did not go to war, or who did, but stayed healthy in later years.
The findings suggest that at least some people with Gulf War Syndrome may be suffering primarily from damage to their nervous systems. The researchers theorize the the damage was caused by chemical compounds, such as pesticides, bug repellents and possibly poison gas, that interacted with each other and became especially damaging.
The new research, described yesterday at a news conference here, comes a day after a panel of experts appointed by President Clinton released a report saying exposures to toxic chemicals, including nerve gas, during the Gulf War were unlikely to explain chronic illnesses that some veterans are reporting. Most research to date has also failed to find such a connection.
The three new studies, to be published next week in the Journal of the American Medical Association, differed from previous research in that they tried to determine if symptoms were related to specific exposures or combinations of exposures. Scientists at the University of Texas Southwestern Medical Center in Dallas conducted an examination of illness in a Navy construction battalion.
Because of the research methods and the tentative nature of the findings, the studies will have to be confirmed by other laboratories before most scientists will be convinced that nervous system damage is the main cause of chronic illness among Gulf War veterans.
For example, the research used complicated statistical methods to find patterns in the answers veterans gave to a long questionnaire about their health and their experiences in the gulf. In addition, the nervous system abnormalities the scientists found were so mild and variable that an ill veteran could not be reliably distinguished from a healthy one. But as a group, ill veterans could be distinguished from healthy ones by overall test results.
The lead scientist in the three studies, Robert W. Haley, asserted yesterday the findings will clear up much of the confusion surrounding chronic illness among some of the 697,000 men and women who served in the campaign to drive the Iraqi army out of Kuwait.
"I think this will give a lot of veterans heart," he said. "It will give confidence to the veterans and their physicians that something real is going on. . . . It probably explains all these unusual symptoms."
There is no formal medical definition of Gulf War Syndrome. The most common symptoms reported by veterans are mood changes, difficulty concentrating, muscle and joint pain, skin rashes and diarrhea. It is not known how many people have such complaints.
Researchers tried to contact all 606 veterans of the Naval Reserve 24th Mobile Construction Battalion. They reached and got answers from 249, or about 40 percent. They asked about symptoms in detail, such as the anatomical location of tingling sensations or numbness, or whether "fatigue" meant day-long sleepiness or an early tiring of specific muscles.
Using the answers, as well as knowledge of what kind of nerve damage causes specific symptoms, the researchers constructed six relatively distinct syndromes. One was characterized by cognitive problems; one by confusion and loss of balance; one by muscle pain and weakness, accompanied by tingling in the hands and feet; one by clumsiness combined with fears of being trapped; one by fever and swollen lymph nodes; and one by tingling around the mouth and face, combined with difficulty controlling bowel and bladder function.
In another study, they tried to determine whether the first three syndromes were associated with any pattern of exposure veterans reported.
They found veterans falling in the "impaired cognition" category were more likely to have worn pet flea collars to ward off insects while in the gulf than were other soldiers. (This strategy against insects was not sanctioned by the military.)
People with the confusion-and-balance-problems syndrome were more likely to have reported they believed they had experienced a chemical weapons attack, and also were more likely to have been in northeastern Saudi Arabia on a day in January 1991, when some soldiers say nerve gas wafted over American troops. The veterans with the muscle-pain-and-weakness syndrome were heavier users of DEET than were other soldiers. DEET is the active ingredient in most bug repellents, including the one issued in the Gulf War.
The Texas researchers believe all six syndromes are variations of a kind of nerve damage called "organophosphate-induced delayed polyneuropathy" (OPIDP). Scientists have known for more than 40 years that some pesticides can cause this problem.
Lead scientist Haley said new research suggests DEET, nerve gases and a drug called pyridostigmine (which many troops took briefly as protection against possible nerve gas attack) can cause OPIDP when used or encountered in combination. Normally, however, OPIDP emerges one to six weeks after exposure, and most veterans reporting chronic illness say their symptoms began months, or years, after returning from the gulf. Preliminary findings of the studies were presented to the Presidential Advisory Committee on Gulf War Veterans' Illnesses last year. The committee, however, used only peer-reviewed research in reaching its conclusions, and the Texas research had not yet advanced to that stage.
Philip J. Landrigan, a physician and one of the 12 members of the presidential committee, wrote an editorial in the journal analyzing the Texas research, which he called "ambitious and sophisticated." At the news conference, he said the studies "raise the possibility of toxic exposure [as a cause of disease], but in my opinion does not pin it to the ground."
The research was funded in part by the Perot Foundation. Billionaire and former presidential candidate Ross Perot has long had an active interest in military and veterans affairs.
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