Exposure to welding fumes is associated with acute systemic inflammatory responses

Aims: To investigate the acute systemic inflammatory response to welding fume exposure. Methods: Twenty four welders (42% smokers) and 13 non-exposed controls (23% smokers) were monitored at a welding school. Exposure to fine particulate matter (PM 2.5 ) was assessed using cyclone samplers. Markers of systemic inflammation, including C-reactive protein (CRP), fibrinogen, and white blood cell (WBC) levels, were determined in peripheral blood samples collected at baseline and after 5.3 (SD 1.0) hours of exposure. Results: The median PM 2.5 concentration for welders was 1.66 mg/m 3 , which was significantly greater than that for controls (0.04 mg/m 3 ). Compared to non-smokers, smokers had a significantly higher baseline WBC count, but comparable levels of CRP and fibrinogen. In non-smokers, welding fume exposure was associated with a significant increase in WBC and neutrophil counts immediately following exposure (+0.8×10 3 /μl, 95% CI 0.1 to 1.6, and +1.0×10 3 /μl, 95% CI 0.4 to 1.7, respectively). A significant decrease in fibrinogen levels was observed in non-smokers (−32 mg/dl, 95% CI −63 to −1). No significant changes in WBC, neutrophil, and fibrinogen levels were found in smokers. Sixteen hours after welding exposure, CRP levels were found to be significantly increased in both non-smokers and smokers (0.90 mg/l, 95% CI 0.17 to 1.64). PM 2.5 concentrations were found to be significantly associated with absolute neutrophil counts in non-smokers, and CRP levels in both non-smokers and smokers. Conclusions: High levels of welding fume exposure induce acute systemic inflammation in a relatively young, healthy working population. These results also suggest that smoking may modify the effect of welding fume exposure on specific inflammatory markers.