Positive human health effects of wearing a respirator in a swine barn.

STUDY OBJECTIVES A study was conducted to evaluate the acute health effects of wearing an N-95 disposable respirator in a swine confinement facility. DESIGN A crossover trial design was used in the study. SETTING The study was carried out at the research facilities of the Centre for Agricultural Medicine, the Royal University Hospital, and the Prairie Swine Centre Inc, Saskatoon, Saskatchewan, Canada. PARTICIPANTS Twenty-one nonsmoking healthy male subjects with no previous swine barn exposure participated in the study. INTERVENTIONS The subjects participated in a laboratory session (baseline day), a 4-h exposure in a traditional swine room wearing the respirator (intervention day), and a 4-hour exposure in a traditional swine room without a respirator (nonintervention day). MEASUREMENTS Lung function, methacholine challenge tests, blood counts, nasal lavage, and cytokines in serum and nasal lavage fluid. RESULTS Mean (+/- SE) shift change in FEV(1), from preexposure to postexposure, was highest on nonintervention day (-8.1+/-1.01%) and was significantly different from intervention day (0.32+/-0.62%; p<0.0001) and baseline day (1.57+/-0.51%; p<0.0001). Similar patterns were observed in the mean values of the provocative concentration of a substance (methacholine) causing a 20% fall in FEV(1) (nonintervention day, 130.4+/-36.9 mg/mL; intervention day, 242.0+/-38.0 mg/mL; and baseline day, 328.0 mg/mL +/-34.1 mg/mL). Significant increases in serum neutrophil levels and nasal cell counts were observed on the nonintervention day in comparison to the baseline and intervention days. Significant increases also were found in the levels of cytokines interleukin (IL)-6 and IL-8 in nasal lavage fluid and in the levels of IL-6 in serum for the nonintervention day in comparison to the other 2 days. CONCLUSIONS The results demonstrate that an N-95 disposable respirator can help to significantly reduce acute negative health effects in subjects not previously exposed to a swine barn environment.