Workplace-related chronic cough on a mushroom farm.
BACKGROUND
Mushroom spores have frequently been associated with respiratory allergy. The aims of this study were to elucidate the incidence and causes of chronic cough in a mushroom farm.


METHODS
Participants were 69 mushroom workers who produce Hypsizigus marmoreus (Bunashimeji) and 35 control subjects. We excluded six workers because they had had asthma or allergic rhinitis before working. Participants completed a cross-sectional health survey 2 years after starting work at the mushroom farm.


RESULTS
The mean airborne endotoxin levels in the harvesting and packing rooms were approximately 60-fold higher than those in the offices. Of 63 workers, 42 workers (67%) reported chronic cough after working on this farm, 19 workers had no cough, while 2 workers had hypersensitivity pneumonitis develop to the spore, which has been previously reported by us. Of the 42 workers with cough, 6 workers had organic dust toxic syndrome (ODTS), 18 workers had postnasal drip syndrome, 15 workers had cough variant asthma, and 3 workers had eosinophilic bronchitis. Seventy-one percent of the workers noticed the cough in the first 3 months, and the mean latent period in ODTS workers was the shortest. The cough had a trend to improve or disappear after weekend holidays. Bronchial hyperresponsiveness but not FEV(1)/FVC% in the 42 workers with cough was significantly (p < 0.001) increased as compared with the control subjects.


CONCLUSIONS
Working on a mushroom farm carries a significant risk for chronic cough from inhalation of mushroom spores, and we suggest that elevated airborne endotoxin on this farm is the cause.
Tanaka
Hiroshi
H
Third Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan. tanakah@sapmed.ac.jp
Saikai
Toyohiro
T
Sugawara
Hiroyuki
H
Takeya
Isao
I
Tsunematsu
Kazunori
K
Matsuura
Akihiro
A
Abe
Shosaku
S
D000328:Adult; D000363:Agaricales; D000368:Aged; D000395:Air Pollutants, Occupational / Q000009:adverse effects / Q000032:analysis; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D003371:Cough / Q000209:etiology*; D003430:Cross-Sectional Studies; D004731:Endotoxins / Q000009:adverse effects / Q000032:analysis; D005203:Farmer's Lung / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D013170:Spores; D014797:Vital Capacity / Q000502:physiology
D000395:Air Pollutants, Occupational; D004731:Endotoxins