Exploratory Look at Coagulatory Changes Associated with Wildland Firefighting in the Wildland Firefighter Exposure and Health Effect Study.

IntroductionThe purpose of this study was to investigate coagulatory changes across multiple wildfire seasons among wildland firefighters.MethodsWe evaluated data on 127 federal wildland firefighters. Pre- and post-season and pre- and post-shift wildland fire response measurements were obtained, including venous blood samples analyzed for platelet closure time; prothrombin time, partial thromboplastin time, and activated partial thromboplastin time; lipids (cholesterol, low-density lipoprotein, high-density lipoprotein, and triglycerides); high-sensitivity C-reactive protein; and complete blood cell counts with differential (hemoglobin, hematocrit, red blood cells, white blood cells, lymphocytes, monocytes, neutrophils, basophils, and eosinophils).ResultsPre- to post-season, there were decreases in high-sensitivity C-reactive protein and prothrombin time; no change in partial thromboplastin time, platelet count, and platelet closure times; and increases in white blood cells, hemoglobin, and hematocrit. Changes over a shift showed that white blood cells, lymphocytes, monocytes, neutrophils, and high-sensitivity C-reactive protein increased and eosinophils and partial thromboplastin time decreased. Platelet number was unchanged, but platelet closure time was prolonged.ConclusionWe found no evidence of increased coagulatory potential following a season of firefighting activity and only modest changes in white blood cells, suggesting that there may not be long-term increased thrombotic potential (formation of blood clots) with wildland firefighting. We found conflicting evidence of increased and decreased coagulatory potential following a single shift of wildland firefighting, although neither the procoagulatory nor anticoagulatory shifts were of great magnitude.