Firefighters are exposed to a,complex mixture of chemical and physical hazards in the course of their work; some of these hazards have been identified as known or suspected carcinogens. Prior studies have indicated possible increased occupational risks of cardiovascular disease as well as brain, lymphopoietic, bladder, kidney, and possibly lung cancers among firefighters. Because most of the previous firefighter studies are based on mortality, the full extent of firefighters' cancer risk is not yet known. This retrospective cohort study of cancer incidence and general mortality was conducted among a group of Florida professional firefighters certified between 1972 and 1999. In addition, proportional mortality ratio (PMR) studies were performed for professional and volunteer firefighters. A total of 1,022 cancer cases and 1,449 deaths were identified in this cohort of 35,777 male (505,612 person-years) and 2,165 female (19,866 person-years) Florida professional certified firefighters. The firefighters were consistently healthier than the general Florida population. The risk of cardiovascular, respiratory, digestive, and genitourinary diseases, external causes, overall cancer, and some site-specific cancers (such as lung cancer and buccal/pharynx cancers) was significantly decreased. Among male professional firefighters, the incidence of bladder cancer [SIR = 1.29 (95% confidence interval = 1.01- 1.62)], testicular cancer [1.60 (1.20-2.09)], and thyroid cancer [1.77 (1.08-2.73)] was significantly elevated, as was thyroid cancer mortality [SMR = 4.82 (1.30-12.30)]. In a subcohort restricted to the male professional firefighters certified between 1972 and 1976, the incidence of bladder cancer [SIR = 1.49 (1.13-1.94)], colon cancer [1.47 (1.13- 1.87)], prostate cancer [1.35 (1.15-1.56)], and skin cancer [1.61 (1.22-2.08)] was significantly increased. Female firefighters had mortality patterns similar to those experienced by Florida women for all diseases but atherosclerotic heart disease [SMR = 3.85 (1.66-7.58)]; elevated cancer incidence risk for kidney [SIR = 6.25 (1.26 18.3)] and thyroid [3.97 (1.45-8.65)] was also observed. Thyroid cancer incidence was also significantly increased among male Hispanic firefighters [SIR = 11.10 (2.99-28.50)]. In conclusion, this study found a significantly increased risk of thyroid, prostate, colon, and bladder cancer among male firefighters. The increase in bladder cancer risk does not appear to be related to tobacco usage. The presence of carcinogens in the firefighting environment warrants further investigation in this population.
Department of Epidemiology and Public Health, University of Miami School of Medicine, 1801 NW 9th Ave., Ste. 200, Miami, FL 33136