Gulf War Veterans' Health: Medical Evaluation of a U.S. Cohort

Figure. *Cohort obtained from the U.S. Department of Defense Manpower Data Center, Monterey, California. Deployed cohort included
all deployed troops, and nondeployed cohort was approximately half of all nondeployed troops in service between September
1990 and May 1991. † Stratified random sampling applied to the U.S. Department of Defense cohort to adequately represent women,
reservists, and National Guard members. ‡ Stratified random sampling applied to participants in the 1995 study to select by
geographic proximity to 1 of 16 participating Veterans Affairs Medical Centers. § We initially invited 2084 veterans to participate.
To achieve examined groups of equal size, we invited an additional 799 veterans to participate in the fourth solicitation
wave of 50 veterans per site.
Sample selection flowchart.
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Ann Intern Med
June 7, 2005
vol. 142
no. 11
881-890