Increase in airway hyperresponsiveness among workers exposed to methylene diphenyldiisocyanate compared to workers exposed to toluene diisocyanate ata petrochemical plant in Korea
As. Jang et al., Increase in airway hyperresponsiveness among workers exposed to methylene diphenyldiisocyanate compared to workers exposed to toluene diisocyanate ata petrochemical plant in Korea, AM J IND M, 37(6), 2000, pp. 663-667
Background The purpose of this study was to investigate the prevalence of a
irway hyperresponsiveness induced by methylene diphenyldiisocyanate (MDI) a
nd toluene diisocyanate (TDI) at a petrochemical industry complex in Korea.
Methods Questionnaires, allergic skin test, and nonspecific airway hyperres
ponsiveness (AHR) were studied in 64 exposed workers and 27 control subject
s. Questionnaires included questions about symptoms of cough, wheezing, che
st tightness, dyspnea, rhinorrhea sneezing, itching, stuffiness, tearing, u
rticaria, sore throat, and exacerbating time. Methacholine challenge tests
were done. Bronchial responsiveness (BRindex) defined as log (% fall in FEV
1)nog (last concentration of methacholine +10).
Results Prevalence of AHR (PC20 FEV1 < 16.0 mg/mL of methacholine) was high
er in MDI-exposed workers than in TDI-exposed workers [4/20 (20%) vs. 2/42
(4.7%), P < 0.05]. Twenty-three workers (39%) of all subjects had respirato
ry 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 work
ers exposed to TDI or MDI without respiratory symptoms (n = 41), had signif
icantly higher BRindex (0.82 +/- 0.06 vs. 0.60 +/- 0.02, P < 0.05). FEV1 wa
s significantly negatively correlated with BRindex (r = -0.253, P < 0.05).
BRindex was not correlated with atopy, smoking status, and exposure duratio
n.
Conclusion These findings suggest that workers exposed to MDI are at a high
er risk of asthma in comparison with TDI-exposed workers and control subjec
ts at a petrochemical plant in Korea. (C) 2000 Wiley-Liss, Inc.