Exposure to pesticides, nerve agents and other chemicals may explain the chronic health problems experienced by up to one-third of Gulf War veterans, US researchers said.
Researchers said an analysis 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.
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 worldwide.
Dr Golomb's 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.
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," Dr Golomb wrote in the Proceedings of the National Academy of Sciences.
She believes genetic variants make some people more susceptible to such chemicals, and, when exposed, these people had a higher risk of illness.