Trends In Injury From Hot Weather Exposure In Us Army Soldiers

Abstract

2112 Hot weather related injury (HWRI) tragically still takes the lives of Army soldiers and is a persistent cause of morbidity, lost duty time, and decreased effectiveness in military operations and training. Previous research demonstrates that soldiers who are overweight, not physically fit, and/or unacclimatizated to hot weather are at greater risk. Despite these well-characterized risk factors however, identification of high at risk U.S. military subpopulations and characterization of HWRI hospitalization trends are still needed. PURPOSE: Our objective was to identify high-risk subgroups while documenting Army HWRI hospitalization trends between 1980 and 2002. Methods: Data were obtained from the U.S. Army Research Institute of Environmental Medicine's (USARIEM) Total Army Injury and Health Outcomes Database (TAIHOD). Hospitalizations with the following ICD-9-CM diagnosis codes were liberally included: 992.0–992.9 (heat cramps, heat exertion, heat stroke, heat syncope, and other unspeci. ed), 276.0 (hyperosmolality), 276.1 (hypoosmolality), 994.4 (exhaustion due to exposure), and 994.5 (exhaustion due to excessive exertion). We also used STANAG injury cause codes 800–809 (Excessive heat or insulation). Gender, age, race/ethnicity, type and cause of injury, home of record, rank, and years of military service were important covariates. Results: Between 1980 and 2002, 5146 soldiers were hospitalized for HWRI (12 deaths). Women in general were hospitalized 25% more frequently than men, while Caucasians were hospitalized more frequently than their Hispanic and African American counterparts. Soldiers under the age of 25, and in particular those under the age of 20, had the highest hospitalizations rate. Activity codes cause indicate that 84% of HWRI hospitalizations occurred on-duty during organized training. The HWRI hospitalization rate, after peaking at 52.2/100,000 in 1991, had decreased gradually to 24.2/100,000 by 2002. Conversely, more serious heat stroke cases gradually increased from 5.4/100,000 in 1991 to 10.1/100,000 in 2002. Conclusions: Most of the HWRI reported in this study occurred while on duty; the data demonstrate a clear need for primary prevention and control measures. Reduction of HWRI may be achieved by targeting specific subpopulations (e.g., initial entry training, women in general). Further investigation is immediately needed to examine the apparent increase in heatstroke cases.