Evidence for a deployment-related Gulf War syndrome by factor analysis.

To identify a syndrome unique to Gulf War veterans, the authors applied an exploratory factor analysis to the 47-symptom correlation matrix of 10,423 Gulf War and 8,960 non-Gulf War veteran respondents. A separate factor analysis was performed for Gulf War and non-Gulf War veterans, and the resulting 6 factors were compared between the 2 groups. Five of the factors were very similar in the 2 groups; however, 1 of the factors in the Gulf War group, but not the non-Gulf War group, contained a cluster of symptoms consistent with neurological impairment. Symptoms specific to this factor were blurred vision, loss of balance/dizziness, tremors/shaking, and speech difficulty. The Gulf War veterans who had all of the aforementioned symptoms (n = 277) also reported exposures to several putative risk factors at a rate 3 or more times higher than other Gulf War veterans. This finding suggests a possible syndrome related to Gulf War deployment, which requires objective supporting clinical evidence.