By Julie Steenhuysen
CHICAGO, March 10 (Reuters) - Exposure to pesticides, nerve agents and other chemicals may explain the chronic, multi-symptom health problems experienced by up to one-third of Gulf War veterans, U.S. researchers said on Monday.
They said an analysis of a host of studies offers compelling evidence that the fatigue, muscle or joint pain, memory and sleep problems, rashes and breathing troubles experienced by these veterans are due to chemicals known as acetylcholinesterase inhibitors and organophosphates, which includes nerve gas.
"Convergent evidence now strongly links a class of chemicals -- acetylcholinesterase inhibitors -- to illness in Gulf War veterans," Dr. Beatrice Golomb of the University of California, San Diego, said in e-mailed comments.
She said some of the chemicals linked to these illnesses continue to be used in agriculture, and in homes and offices for pest control in the United States and throughout the world.
Golomb's prior research found that pills known as carbamate pyridostigmine bromide were given to service members to protect against exposure to nerve agents -- a practice that has since been discontinued.
For the latest study, Golomb combed through several studies linking Gulf War veterans' symptoms with all of the chemicals. She found that returning Gulf War veterans who had been exposed to chemicals suffered multi-symptom complaints at a higher rate than those who were not deployed, or who were deployed elsewhere.
"Evidence, taken together, provides a case for causal connection of carbamate, organophosphates and acetylcholinesterase inhibitor exposure to illness in Gulf War Veterans," Golomb wrote in the Proceedings of the National Academy of Sciences.
She also found a link between the amount of exposure to the chemicals and how common symptoms were in these veterans.
Golomb believes genetic variants make some people more susceptible to such chemicals, and when exposed, these people had a higher risk of illness.
"A lot of attention has gone to psychological factors in illness in Gulf War veterans," Golomb said. But she said the ground conflict in the Gulf War lasted only four days, unlike the current conflict.
"Psychological stressors are inadequate to account for the excess illness seen," she said.
She said this knowledge should help protect troops from such problems arising in the future. Her team is also looking at ways to mitigate symptoms in Gulf War veterans.
The study is available online here. (Editing by Maggie Fox and Jackie Frank)