Airway inflammation in cement production workers

ObjectiveCement aerosol exposure is associated with increased morbidity of airway disease among exposed workers. Our aim was to compare levels of inflammatory cells and soluble inflammatory markers in induced sputum samples from cement production workers between exposed and unexposed periods, and to compare these variables between cement workers and references.Methods35 healthy, non-smoking aerosol-exposed cement production workers from Norway provided a blood sample and performed induced sputum and spirometry after 5 days without exposure and during a period of exposure. These values were compared with those from an internal low-exposed reference group of 15 office workers and an external reference group of 39 non-exposed workers. Differential cell counts and inflammatory markers were assessed.ResultsMedian thoracic aerosol concentration over one work shift (8 h) was 0.6 mg/m3 (range 0.2–8.1) in maintenance workers and 1.75 mg/m3 (0.2–15.5) in furnace department workers. The median percentage of airway neutrophils in both groups combined was 51% (32–66) in the exposed period, which was significantly higher than in both the unexposed period (38%; 23–55) (p=0.04) and the external reference group (30%; 19–44) (p=0.001). Median interleukin-1β concentration was elevated compared with both office workers (p=0.05) and the external reference group (p=0.006).ConclusionsA significantly higher percentage of neutrophils was observed in cement production workers during the exposed period compared with both the non-exposed period and the external reference group, and corresponded with elevated IL-1β concentration. These data indicate that cement aerosol exposure in concentrations below the Norwegian occupational limits (respirable dust 5 mg/m3; total dust 10 mg/m3) may cause airway inflammation.