Associations between bioaerosols, lung function work-shift changes and inflammatory markers: A study of recycling workers

Objectives We investigated associations between bioaerosol exposures and work-shift changes in lung function and inflammatory markers among recycling workers. Methods Inhalable dust was measured with personal samplers and analyzed for endotoxin, bacteria, and fungi (incubated at 25 degrees C and 37 degrees C) levels. Lung function (FEV1, FVC) was measured before and after work-shifts and serum concentrations of inflammatory markers (CRP, SAA, CC16, IL1B, IL2, IL4, IL5, IL6, IL8, IL10, IL13, and TNF) after the shift. Associations were explored by linear mixed-effects models. Results We included 170 measurements from 88 production workers exposed to inhalable dust, endotoxin, bacteria, and fungi (25 degrees C and 37 degrees C) at geometric mean levels of 0.6 mg/m(3), 10.7 EU/m(3), 1.6x10(3) CFU/m(3), 4.4x10(4) CFU/m(3), and 10(3) CFU/m(3), respectively, and 14 administrative workers exposed at 7-fold lower levels. No associations were observed between bioaerosol exposures and work-shift change in lung function. IL2, IL6, IL10, and TNF concentrations were positively associated with inhalable dust levels, SAA and IL6 with bacteria, CRP, SAA, IL8, and TNF with fungi (25 degrees C or 37 degrees C), with the latter being the only statistically significant finding (exp(beta) 1.40, 95% confidence interval 1.01-1.96). Conclusions This study of recycling workers exposed to bioaerosol levels generally below those of farmers and compost workers and above background levels did not indicate any acute effect on lung function. Several inflammatory markers tended to increase with exposure, suggesting a systemic effect. Future research should combine data from bioaerosol-exposed workers to uncover health risks that may form the basis for health-based occupational exposure limits.