Induced sputum evaluation in microwave popcorn production workers

Objective: Severe airways obstruction and bronchiolitis obliterans have been reported in microwave popcorn production workers and attributed to inhalation of flavoring agents. We investigated whether exposure to flavoring agents is associated with airways inflammation in popcorn production workers. Methods: Fifty-nine workers with high exposures and 22 patients with low exposures to flavoring vapors completed a questionnaire, spirometry, and sputum induction. Sputum cell counts were categorized as "high" if greater than (and "low" if less than or equal to) the median cell counts of a healthy external control group (n = 24). We compared high- and low-exposure groups as well as all workers with control subjects. Results: Neutrophil concentrations in nonsmoking workers were significantly higher than those of the healthy nonsmoking control group (p < 0.05). The smoking-adjusted odds ratio for high neutrophil count (> 1.63 X 10(5)/mL) was 3.8 (95% confidence interval, 1.3 to 11.5) in the high-exposure group compared with the low-exposure group. Sputum interleukin-8 and eosinophil cationic protein levels were higher in high-exposure workers than in low-exposure workers (p < 0.05). For the worker group, mean values of FEV1 percentage of predicted and FEV1/FVC percentage of predicted were > 95%. There were no relationships between sputum characteristics and the presence of airways obstruction. Conclusions: High exposure to popcorn flavoring agents is associated with neutrophilic airway inflammation in popcorn production workers. These data provide further evidence that popcorn production workers face a significant occupational hazard through exposure to flavoring agents.