Non-Hodgkin's Lymphomas in U.S. Navy Personnel

Abstract

Non-Hodgkin's lymphomas are one of the most commonly occurring cancers in the age groups heavily represented in the U.S. Navy. The Navy has a wide range of potential occupational exposures. This study was initiated to identify any occupational associations of non-Hodgkin's lymphomas that may adversely affect naval readiness. The objective of this study was to compare the incidence of non-Hodgkin's lymphomas in U.S. Navy active duty enlisted personnel during the period 1974–1983 with the general U.S. population, and to assess if risk varied by naval occupation or length of service. The Naval Health Research Center's computer-based disease registry was used to conduct a prospective study of all white U.S. Navy enlisted men during 1974–1983 to test for the existence of any short-term risk possibly due to occupation. Men in 80 occupations, ranging from clerk to journalist to machinist and boiler operator were observed for 3,704,864 person-years; mean length of service was 5.1 yr, but 19% of person-years were contributed by men who had served at least 11 yr. Incident cases of non-Hodgkin's lymphomas were identified and verified using Medical Board findings or review of original medical records. Average annual age-specific and age-adjusted incidence rates were calculated.

Examination of pathology records and medical review boards confirmed 68 cases of non-Hodgkin's lymphomas. The annual age-adjusted incidence rate per 100,000 person-years in Navy men was significantly lower than in the U.S. Surveillance, Epidemiology, and End Results (SEER) population, probably due to screening and other selection factors associated with Navy service that result in a healthy worker effect. Risk was unrelated to length of service, and no occupational groups showed a significant excess risk. Results of this study indicate there is no overall or occupation-specific increase in risk of non-Hodgkin's lymphomas in the U.S. Navy which was detectable in this relatively short-term prospective study.