Incidence of Hodgkin and Non-Hodgkin Lymphomas: Comparison of the Military and General Population

Background: Lymphoma risk varies by demographics, environmental/occupational exposures, and medical care between active-duty service members (ADSM) and the general US population (GUSP). This study compared age-adjusted incidence rates and trends of Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) between these groups. Methods: Data were obtained from the Department of War's Central Cancer Registry and the National Cancer Institute's Surveillance, Epidemiology, and End Results database, including individuals aged 18–59 diagnosed with lymphoma between 1998 and 2014. Incidence rate ratio (IRR) and 95% CIs were calculated to compare the incidence of HL and NHL between ADSM and GUSP, with analyses stratified by sex, race, age, stage, and histology. Results: Lymphoma incidence was lower in ADSM than GUSP (HL: 0.93 [0.86, 1.00]; NHL: 0.82 [0.77, 0.88]); specifically, for men (HL: 0.89 [0.82, 0.97]; NHL: 0.69 [0.64, 0.74]), White (HL: 0.87 [0.80, 0.95]; NHL: 0.80 [0.73, 0.86]), and Black individuals (HL: 0.82 [0.68, 0.99]; NHL: 0.61 [0.51, 0.73]). Incidence was lower among ADSM aged 18–39 (HL: 0.91 [0.84, 0.99]; NHL: 0.74 [0.68, 0.81]), but similar at ages 40–59. ADSM had lower HL (early-stage: 0.86 [0.77, 0.96]; nodular lymphocyte predominant: 0.88 [0.80, 0.97]) and NHL (early stage: 0.86 [0.77, 0.96]; advanced stage: 0.87 [0.78, 0.97]; diffuse large B-cell: 0.65 [0.58, 0.74]; other histologies: 0.83 [0.74, 0.93]) incidence. Conclusion: Lymphoma incidence was lower in ADSM than GUSP, particularly among men and younger individuals. Based on prior literature, this may be related to the healthier status of ADSM and earlier detection and treatment of medical conditions that can predispose to lymphoma. Diminished differences between the two populations for older individuals may reflect cumulated military-related exposures within a generally healthier population.