Esteves, FilipaMadureira, JoanaBarros, BelaAlves, SaraPires, JoanaMartins, SandraOliveira, MartaVaz, Josiana A.Slezakova, KlaraPereira, Maria do CarmoFernandes, AdíliaMorais, SimoneGuimarães, João TiagoBonassi, StefanoTeixeira, João PauloCosta, Solange2025-06-132025-06-132025Esteves, Filipa; Madureira, Joana; Barros, Bela; Alves, Sara; Pires, Joana; Martins, Sandra; Oliveira, Marta; Vaz, Josiana A.; Slezakova, Klara; Pereira, Maria do Carmo; Fernandes, Adília; Morais, Simone; Guimarães, João Tiago; Bonassi, Stefano; Teixeira, João Paulo; Costa, Solange (2025). Impact of occupational exposure to wildfire events on systemic inflammatory biomarkers in Portuguese wildland firefighters. Environmental Research. ISSN 0013-9351. 277, p. 1-90013-9351http://hdl.handle.net/10198/34601While occupational exposure as a firefighter is considered a dangerous occupation, research on the underlying mechanisms remains limited, particularly in wildland firefighters. Inflammation, a key effect of wildfire expo- sure, plays a significant role in the development of various diseases. The current study aims to investigate the impact of wildland firefighting exposure on the levels of pro-inflammatory systemic biomarkers. A pre-post study design investigated 59 wildland firefighters comparing data collected after participation in a wildfire event (Phase II) with data obtained before wildfire season (Phase I). Data on demographics, lifestyle, health and occupational-related factors were assessed. Exposure factors, such as fire combat (e.g., exposure duration), were also registered. Inflammatory biomarkers (i.e. interleukin-6 [IL-6], interleukin-8 [IL-8], tumor necrosis factor α [TNF-α] and high-sensitivity C-reactive protein [hs-CRP]) and hydroxylated polycyclic aromatic hydrocarbons metabolites (1-OHNaph+1-OHAce, 2-OHFlu, 1-OHPhen, 1-OHPyr) were analysed in blood and urine samples, respectively. Serum IL-8 and IL-6 levels were significantly increased after wildland fire combat. IL-8 levels were 2.62 times higher (95 % CI: 1.96–3.50; p < 0.01), whereas IL-6 levels were 1.25 times higher (95 % CI: 1.00–1.57; p = 0.04). Furthermore, IL-8 levels were significantly correlated with urinary 2-hydroxyfluorene levels and fire combat duration (>12 h). In addition, the mean hs-CRP level, in both phases, was above 3.0 mg/L, indicating a potential risk for cardiovascular events. Given the long-term health implications of fire- fighting occupational exposure, biomonitoring and early detection of occupational risks are essential for pro- tecting firefighters’ health. Protective measures must be urgently implemented to enhance occupational health and strengthen preventive strategies in this sector.engWildland firefightersInflammationCytokinesBiomarkersWoodsmoke exposureFirefightingjournal article10.1016/j.envres.2025.121608