Occupational exposure to airborne silica, dust containing silica (total dust), and dust without silica (mostly iron oxide) have been known to cause cardio-respiratory disease. However, with dust exposure in general, disease detection usually occurs in advanced stages of the disease process, in part due to the lack of sensitivity of current diagnostic tools that would allow for earlier detection of the disease.Methods
Using a multiplexed bead-based assay, we measured plasma levels of 11 immune/inflammation markers in a cross-sectional study of 134 current workers employed in various operations in mining and processing of taconite (a low grade iron ore). These are markers previously demonstrated to be related to silica exposure and/or restrictive/obstructive lung disease in other settings. We used linear regression models to examine the associations between quartiles of silica, total dust, and dust without silica with levels of markers adjusting for age, BMI, gender, and smoking.Results
In adjusted models, of the 11 markers selected, C-reactive protein (CRP) had the strongest association and showed a graded response across quartiles of silica. Total dust and dust without silica had little association with these markers.Conclusions
This study suggests that exposure to silica, total dust, and dust without silica may be associated with alterations in CRP. Total dust and dust containing iron oxide, in general, do not demonstrate associations with other markers in our study. Further research is needed to understand the potential utility of CRP as a marker linking occupational exposures and health outcomes in taconite workers.