organic solvents, vehicle exhaust fumes, and insecticides. Alarms sounded often and troops responded by donning the confining protective gear and ingesting PB as an antidote to nerve gas. In addition to the alarms, there were widespread reports of dead sheep, goats, and camels, which troops were taught could be indication of the use of chemical or biologic weapons. The sounding of the alarms, the reports of dead animals, and rumors that other units had been hit by chemical warfare agents caused the troops to be concerned that they would be or had been exposed to such agents.
Despite the small numbers of US personnel injured or killed during combat in the Gulf War, the troops, as in any war, faced the fear of death, injury, or capture by the enemy. After the war, there was the potential for other exposures, including US demolition of a munitions storage complex at Khamisiyah, Iraq, which—unbeknownst to demolition troops at the time—contained stores of sarin and cyclosarin. The potential exposures to sarin and cyclosarin from the Khamisiyah incident have been the subject of specific modeling and health outcome studies. Depending on the dispersion model used to estimate the sarin and cyclosarin plume and troop unit locations, the number of Gulf War veterans who may have been exposed to the nerve agents ranged from an initial estimate of 10,000 troops within 25 km of Khamisiyah in 1997 to more than 100,000 troops using a 2000 model. However, more than 35,000 troops originally considered to have been exposed and notified that they may have been within the plume were subsequently considered to have been unexposed and 37,000 troops were newly identified as being in the hazard area (IOM, 2006b), adding to the confusion of how many troops were actually exposed to nerve agents and at what levels. As stated in Volume 4, “No medical reports by the US Army Medical Corps at the time of the release were consistent with signs and symptoms of acute exposure to sarin” (IOM, 2006b).
The charge to the Volume 4 committee and to the current IOM committee (Update committee) is different from charges to other IOM Gulf War and Health committees in that the Volume 4 and Update committees were not asked to associate health outcomes with specific biologic, chemical, or other agents believed to have been present in the gulf, but rather to examine health outcomes related to deployment to the gulf region in general. The specific charge to the Update committee, as requested by the VA, was to review, evaluate, and summarize the literature on the following health outcomes noted in the 2006 report that seem to appear at higher incidence or prevalence in Gulf War-deployed veterans: cancer (particularly brain and testicular cancer), amyotrophic lateral sclerosis and other neurologic diseases (for example, Parkinson’s disease and multiple sclerosis), birth defects and other adverse pregnancy outcomes, and postdeployment psychiatric conditions. The committee also was to review studies on cause-specific mortality in Gulf War veterans as recommended in the 2006 report. Finally, the committee was to examine the literature to identify any emerging health outcomes.
Thus, the current committee has limited its review to epidemiologic studies of health outcomes published since the last literature search conducted for Volume 4 and those studies included in Volume 4. The studies must compare the health status of Gulf War veterans compared with nondeployed veterans or veterans deployed elsewhere such as Bosnia. Because the committee was not attempting to link health outcomes to any exposures other than deployment to a war zone, for which there is no known animal model, the committee did not review toxicologic, animal, or experimental studies. Where studies attempted to associate health