Leukemia in US Navy Enlisted Personnel

Leukemia is the fourth most commonly occurring cancer in the Navy and in the United States general population between the ages of 15 to 34 years. Historical computerized military career records maintained at the Naval Health Research Center were used to determine person-years at risk (4,072,502 person- years) by demographic characteristics and occupation for active-duty Naval personnel during 1974-1984. Computerized inpatient medical records were searched for first hospitalizations for leukemia. Cases of leukemia (N = 102) are verified using pathology reports or Medical or Physical Evaluation Board findings. For comparisons, age-adjusted incidence rates and Standardized Incidence Ratios (SIRs) were calculated using rates for the U.S. population provided by the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute. The overall age-adjusted incidence rate of leukemia in active-duty Naval personnel was found to be very close to that of the U.S. SEER population (6.0 versus 6.5 per 100,000 person-years). Leukemia cases occurred in a wide range of occupations with differing estimated exposures, implying that leukemia in the young active-duty enlisted Navy population is predominately determined before entrance into service. This finding is intriguing in the light of several studies showing an excess risk of leukemia associated with exposure to electromagnetic fields.