Background Firefighters are at increased risk for select cancers. However, many studies are limited by relatively small samples, with virtually no data on the cancer experience of female firefighters. This study examines cancer risk in over 100,000 career Florida firefighters including 5000 + females assessed over a 34‐year period. Methods Florida firefighter employment records (n = 109 009) were linked with Florida Cancer Data System registry data (1981‐2014; ~3.3 million records), identifying 3760 male and 168 female‐linked primary cancers. Gender‐specific age and calendar year‐adjusted odds ratios (aOR) and 95% confidence intervals for firefighters vs non‐firefighters were calculated. Results Male firefighters were at increased risk of melanoma (aOR = 1.56; 1.39‐1.76), prostate (1.36; 1.27‐1.46), testicular (1.66; 1.34‐2.06), thyroid (2.17; 1.78‐2.66) and late‐stage colon cancer (1.19;1.00‐1.41). Female firefighters showed significantly elevated risk of brain (2.54; 1.19‐5.42) and thyroid (2.42; 1.56‐3.74) cancers and an elevated risk of melanoma that approached statistical significance (1.68; 0.97‐2.90). Among male firefighters there was additional evidence of increased cancer risk younger than the age of 50 vs 50 years and older for thyroid (2.55; 1.96‐3.31 vs 1.69; 1.22‐2.34), prostate (1.88; 1.49‐2.36 vs 1.36; 1.26‐1.47), testicular (1.60; 1.28‐2.01 vs 1.47; 0.73‐2.94), and melanoma (1.87; 1.55‐2.26 vs 1.42; 1.22‐1.66) cancers. Conclusion Male career firefighters in Florida are at increased risk for five cancers with typically stronger associations in those diagnosed younger than the age of 50, while there was evidence for increased thyroid and brain cancer, and possibly melanoma risk in female firefighters. Larger cohorts with adequate female representation, along with the collection of well‐characterized exposure histories, are needed to more precisely examine cancer risk in this occupational group.

BackgroundFirefighters have an increased risk of cancer, but variations in reported results could be due to differences in occupational case ascertainment. This study compares cancer risk estimates generated by identifying firefighters from their occupational title available in the Florida Cancer Data System (FCDS) versus identification by a linkage method between the FCDS and the Florida State Fire Marshal's Office.MethodsFlorida firefighter employment records (1972–2012; n = 109,009) were linked with FCDS data (1981–2014; ~3.3 million records), identifying 3760 primary cancers in male firefighters. Using the FCDS occupational data field we identified 1831 male cancer cases in those classified as firefighters, first‐line supervisors of firefighting and prevention workers, fire inspectors, emergency medical technicians, or paramedics. Age and calendar year‐adjusted odds ratios (aOR) and 95% confidence intervals for firefighters versus non‐firefighters were calculated for both groups.ResultsFor skin cancers the risk estimate for FCDS‐indentified firefighters was substantially lower than in the employment‐record‐linked firefighters (aOR = 1.06; 0.87–1.29 vs. 1.54; 1.37–1.73), but for endocrine system cancers it was greater (aOR = 2.36; 1.77–3.14 vs. 2.08; 1.71–2.53). Remaining cancer risk estimates were in the same direction for the two samples except for lymphoma (aOR = 1.10; 0.90–1.34 vs. 0.86; 0.75–0.99).ConclusionReliance on occupational title in cancer registry records to characterize firefighter cancer risk may result in estimates that are over‐ or underestimated depending on cancer site. The authors recommend moving toward national linkages between cancer registries and certification or other administrative records, which are a vital resource for firefighter cancer research.

Purpose Exposure to endocrine disrupting chemicals (EDCs) are associated with underactive thyroid glands, and possibly autoimmunity. Firefighters are exposed to EDCs from flame retardants; however, the prevalence and risk factor associations of thyroid antibodies among firefighters are unknown. Methods Firefighters attending professional health and safety conferences between November 2018 and January 2020, and with no prior diagnosis of thyroid disease were invited (n=278) to submit a health survey, blood samples, and complete a thyroid ultrasound. The survey assessed for sociodemographic and occupational characteristics, including a history of familial thyroid disease, smoking, firefighter tenure, and job rank, radiation exposure, and mitigation practices of occupational exposures. Serum thyroid peroxidase antibody (TPOAb) was also assessed. Results Approximately 39.9% firefighters evaluated had a positive TPOAb test. The mean age for those TPOAb positive was lower than those who tested negative (41.4 ±7.9 vs 43.1 ±7.9 years, p=0.07) but this difference was not significant. Firefighters with a family history of thyroid disease had a statistically significant higher prevalence of TPOAb compared to those without a family history (60.0% vs. 37.5%, p=0.02); this association remained significant after adjusting for sociodemographic and occupational factors (Odds Ratio 2.99; Confidence interval 1.31 – 6.85). Main conclusions The prevalence of TPOAb is high among firefighters in our study, and family history is a significant determinant of testing positive for TPOAb. Firefighters may benefit from TPOAb and thyroid stimulating hormone tests, and screening for family history of thyroid disease at baseline employee medical check-ups. This finding suggests the need for further studies.