Death among U.S. Air Force basic trainees, 1956 to 1996.

BACKGROUND: Basic military training in the U.S. Air Force exposes recruits to multiple environmental and psychological stressors. Deaths often prompt examination of the training process. METHODS: This retrospective case study evaluates recruit deaths at Lackland Air Force Base between 1956 and 1996 in terms of demographic, clinical, and environmental variables. RESULTS: Eighty-five deaths occurred, with 81% being natural, 13% suicide, 4% accidental, and 2% not classified. Ninety-four percent of recruits who died were male, and 60% were 17 to 19 years of age. The average death rate was 2.8/100,000 recruits. Seven recruits were sickle cell trait (SCT)-positive. The relative risk for nontraumatic deaths between expected SCT-positive and non-SCT-positive populations was 23.53 (confidence interval, 19.55-30.01). Thirty-five percent (30 recruits) died from cardiac causes, resulting in a death rate of 1.0/100,000 trainees. Thirty-three percent (28 recruits) died primarily from infections. Six deaths were due to heat stroke, 11 to suicide, and 3 to accidents. CONCLUSION: As a result of improvements in immunizations, changes in hydration and exercise policies, limited access to vehicles, close supervision, the "buddy system," and the institution of the Navy-Air Force Medical Evaluation Test, only a few deaths occurred in any given year.

Statistical evaluation of population data for calculation of radioactive material transport accident risks.

Calculation of accident dose-risk estimates with the RADTRAN code requires input data describing the population likely to be affected by the plume of radioactive material (RAM) released in a hypothetical transportation accident. In the existing model, population densities within 1/2 mile (0.8 km) of the route centerline are tabulated in three ranges (Rural, Suburban, and Urban). These population densities may be of questionable validity since the plume in the RADTRAN analysis is assumed to extend out to 120 km from the hypothetical accident site. We present a GIS-based population model which accounts for the actual distribution of population under a potential plume, and compare accident-risk estimates based on the resulting population densities with those based on the existing model. Results for individual points along a route differ greatly, but the cumulative accident risks for a sample route of a few hundred kilometers are found to be comparable, if not identical. We conclude, therefore, that for estimation of aggregate accident risks over typical routes of several hundred kilometers, the existing, simpler RADTRAN model is sufficiently detailed and accurate.