Correlates of Positive Thyroid Peroxidase Antibodies Among Firefighters: A Cross-Sectional-Study

Context 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. Context We aimed to determine the prevalence of thyroid peroxidase antibodies (TPOAb) and associated sociodemographic and occupational risk factors among firefighters. 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% of 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 with 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; CI, 1.31-6.85). Conclusion 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.