Exposure to welding fumes is associated with acute systemic inflammatory responses
- 1Department of Environmental Health, Occupational Health Program, Harvard School of Public Health, Boston, MA 02115, USA
- 2Pulmonary and Critical Care Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Correspondence to: Prof. D C Christiani Harvard School of Public Health, Occupational Health Program, Building I, Room 1402, 665 Huntington Avenue, Boston, MA 02115, USA; dchristihsph.harvard.edu
- Accepted 19 October 2004
Abstract
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 (PM2.5) 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 PM2.5 concentration for welders was 1.66 mg/m3, which was significantly greater than that for controls (0.04 mg/m3). 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 (+0.8×103/μl, 95% CI 0.1 to 1.6, and +1.0×103/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). PM2.5 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.
- 95% CI, 95% confidence interval
- ATS, American Thoracic Society
- CRP, C-reactive protein
- PM2.5, particulate matter with an aerodynamic mass median diameter ≤2.5 μm
- PM10, particulate matter with an aerodynamic mass median diameter ≤10 μm
- RBC, red blood cell
- SD, standard deviation
- SEM, standard error of the mean
- WBC, white blood cell
Footnotes
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This study was supported by NIH grants ES09860, ES00002, and CA94715. Dr Kim was supported by Harvard-NIOSH Education and Research Center training grant T42110421 and a NIEHS post-doctoral fellowship T32 ES07069.
