Differential metabolic profiles by training fire exposure in female firefighters

BACKGROUND: Female firefighters face elevated risks for cancer and reproductive disorders, but the underlying metabolic mechanisms remain unclear. OBJECTIVES: This study aimed to identify urinary metabolites and metabolic processes associated with training fire exposure among female municipal firefighters. METHODS: High-resolution metabolomics (HRM) was conducted on urine samples collected before and after live-fire training from female firefighters enrolled in the Fire Fighter Cancer Cohort Study. Linear mixed-effects models, adjusting for age, education, and Hispanic ethnicity, were used to identify differentially expressed metabolites (DEMs) with false discovery rate correction. Functional enrichment analysis (FEA) via metabolite-set enrichment analysis (MSEA) from MetaboAnalyst was performed to identify enriched metabolic processes. A stratified analysis examined the influence of fire types on post-fire metabolic profiles. RESULTS: One hundred female firefighters donated a total of 200 urine samples (100 pre-, 100 post-fire). HRM was performed in four modes including HILIC(+), HILIC(-), C18(+), and C18(-). We identified 200, 300, 280, and 306 metabolites and 10, 9, 23, and 19 post-training fire DEMs from the four modes, respectively. FEA highlighted enrichment of glycerophospholipid metabolism (p < 0.05). Stratified analysis identified 11 DEMs by fire type with greater changes observed following burn room/tower exposures compared to flashover fires. CONCLUSION: Training fire exposure induced widespread metabolic alterations in female firefighters, particularly in pathways related to oxidative stress and cell damage. These findings suggest potential biological pathways linking repeated fire exposure to chronic inflammation and disease risk. Burn room/tower burn exercises elicited more pronounced metabolic shifts than flashover fires.