Increase in airway hyperresponsiveness among workers exposed to methylene diphenyldiisocyanate compared to workers exposed to toluene diisocyanate at a petrochemical plant in Korea

• Published in: American journal of industrial medicine Vol. 37; no. 6; pp. 663 - 667
• Main Authors: Jang, An-Soo, Choi, Inseon-S., Koh, Young Il, Moon, Jai-Dong, Lee, Kang-Jin
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01-06-2000; Wiley-Liss
• Subjects: Adult; Air Pollutants, Occupational - adverse effects; Allergens; Biological and medical sciences; Bronchial Hyperreactivity - chemically induced; Bronchial Hyperreactivity - diagnosis; Bronchial Provocation Tests; bronchial responsiveness (BRindex); Chemical compounds (mineral, organic); Chemical Industry; Chemical, physic and infectious diseases; Chronic obstructive pulmonary disease, asthma; Female; Forced Expiratory Volume - drug effects; Humans; Intradermal Tests; Isocyanates - adverse effects; Korea; Male; Medical sciences; methylene diphenyldiisocyanate; Occupational Diseases - chemically induced; Occupational Diseases - diagnosis; Occupational medicine; Petroleum - adverse effects; Pneumology; Public health. Hygiene-occupational medicine; resiratory tract diseases; respiratory tract diseases; toluene 2,4-diisocyanate; Toluene 2,4-Diisocyanate - adverse effects; toluene diisocyanate; Asia; Korea; Allergy; Questionnaire; Hyperreactivity; Occupational disease; Respiratory disease; Toluene; Bronchus; Occupational exposure; Asthma; Petrochemical industry; Risk factor; Worker; Obstructive pulmonary disease; Comparative study
• ISSN: 0271-3586; 1097-0274
• DOI: 10.1002/(SICI)1097-0274(200006)37:6<663::AID-AJIM11>3.0.CO;2-H

Background
The purpose of this study was to investigate the prevalence of airway hyperresponsiveness induced by methylene diphenyldiisocyanate (MDI) and toluene diisocyanate (TDI) at a petrochemical industry complex in Korea.
Methods
Questionnaires, allergic skin test, and nonspecific airway hyperresponsiveness (AHR) were studied in 64 exposed workers and 27 control subjects. Questionnaires included questions about symptoms of cough, wheezing, chest tightness, dyspnea, rhinorrhea, sneezing, itching, stuffiness, tearing, urticaria, sore throat, and exacerbating time. Methacholine challenge tests were done. Bronchial responsiveness (BRindex) defined as log (% fall in FEV1)/log (last concentration of methacholine +10).
Results
Prevalence of AHR (PC20 FEV1 < 16.0 mg/mL of methacholine) was higher in MDI‐exposed workers than in TDI‐exposed workers [4/20 (20%) vs. 2/42 (4.7%), P < 0.05]. Twenty‐three workers (36%) of all subjects had respiratory symptoms. MDI‐exposed workers, in comparison with control subjects, had higher BRindex (0.73 ± 0.04 vs. 0.62 ± 0.02, P < 0.05). Workers exposed to TDI or MDI who had respiratory symptoms (n = 23), in comparison to workers exposed to TDI or MDI without respiratory symptoms (n = 41), had significantly higher BRindex (0.82 ± 0.06 vs. 0.60 ± 0.02, P < 0.05). FEV1 was significantly negatively correlated with BRindex (r = −0.253, P < 0.05). BRindex was not correlated with atopy, smoking status, and exposure duration.
Conclusions
These findings suggest that workers exposed to MDI are at a higher risk of asthma in comparison with TDI‐exposed workers and control subjects at a petrochemical plant in Korea. Am. J. Ind. Med. 37:663–667, 2000. © 2000 Wiley‐Liss, Inc.