RESPIRATORY-TRACT INFLAMMATION IN SWINE CONFINEMENT WORKERS STUDIED USING INDUCED SPUTUM AND EXHALED NITRIC-OXIDE

Objective: To further define the asthma-like syndrome seen in swine co nfinement workers. Design: A crosssectional study was performed at a s wine confinement facility in rural Nebraska and at the University of N ebraska Medical Center, Omaha, Nebraska. Participants: 24 swine confin ement workers and 14 urban normal control subjects. All subjects compl eted a questionnaire concerning respiratory complaints. We performed h ypertonic saline challenges on the swine confinement workers and contr ol subjects in order to induce expectoration of sputum, Cell counts an d cell differentials were determined in the induced sputum samples. Na sal, mean, and peak exhaled nitric oxide was measured in both groups. Spirometry was also done. Results: Swine confinement workers were sign ificantly more likely to report wheezing, cough, and sinusitis symptom s than controls (p =.003). Macrophages were significantly elevated in the induced sputum samples of the swine confinement workers vs the con trol subjects (0.59 macrophages/mL +/- 0.1 SEM vs 0.36 +/- .16; p = .0 06), while there was no difference in numbers of neutrophils, No eosin ophils were observed. A small elevation in mean exhaled nitric oxide w as seen in the swine confinement workers compared to normal controls ( 11.7 ppb +/- 0.6 SEM vs 10.2 +/- 1.6; p = 0.023). Spirometry values di d not differ statistically between swine confinement workers and the c ontrol group. Conclusions: Swine confinement workers have signs and sy mptoms of lower respiratory tract inflammation when studied using indu ced sputum and exhaled nitric oxide. Findings in the swine confinement workers differ from those in asthmatics and chronic bronchitis.