Hospitalizations for all causes of US military service members in relation to participation in Operations Joint Endeavor and Joint Guard, Bosnia-Herzegovina, January 1995 to December 1997

Since December 1995, the United States has deployed military forces to Bosnia-Herzegovina to participate for varying periods in peacekeeping operations, Throughout the operations, medical surveillance data have been routinely integrated in the Defense Medical Surveillance System. For this analysis,;lll individuals who served in the U,S, armed forces between January 1995 and December 1997 were characterized as participants or nonparticipants in the Bosnia-Herzegovina operations, Each participant's service was divided into predeployment, deployment, and postdeployment phases. End points for analyses were hospitalizations (all causes) in military hospitals, The crude hospitalization rate among nonparticipants (80.9 per 1,000 person-years [p-yrs]) exceeded the rate among participants (56.6 per 1,000 p-yrs), Among participants, the crude hospitalization rate during deployment (84.4 per 1,000 p-yrs) exceeded the rates before deployment (54.7 per 1,000 p-yrs) and after deployment (49.9 per 1,000 p-yrs). Proportional hazards regression procedures were used to control for confounding effects in comparisons of participants and nonparticipants, to account for transitions in deployment-phase exposures at appropriate calendar times, and to adjust for changes in hospitalization criteria that were implemented during the study. Although the crude hospitalization rate after deployment was lower than the rate before deployment, adjusted relative risks were elevated during and after deployment (relative to before deployment).