Soldiers, sailors and airmen who spent a year in the Persian Gulf in 1990 and 1991 did not have a higher rate of death from illness than American servicemen who spent the same time elsewhere, according to a new study.

“We found no evidence of any appreciable number of rapidly fatal illnesses clustered in space and time during the campaign,” a team of Army researchers wrote in today’s Journal of the American Medical Association.

“Claims of an increased risk of unexpected death resulting from potential exposure to vaccinations, anti-chemical agent treatments, oil fires, and chemical or biological weapons were not supported by the data,” the researchers added.

The new study does not address the issue of chronic illness among veterans.

Known popularly as “Gulf War syndrome,” the cluster of symptoms includes fatigue, muscle and joint aches, mood changes, disturbed sleep and skin rashes. No distinct cause for them has been found.