Medline ® Abstracts for References 15,16
of 'Reactive airways dysfunction syndrome and irritant-induced asthma'
Symptoms, lung function, and airway responsiveness following irritant inhalation.
Blanc PD, Galbo M, Hiatt P, Olson KR, Balmes JR
STUDY OBJECTIVE: To estimate the incidence of respiratory symptoms and physiologic abnormalities after inhalation of common irritant chemicals.
DESIGN: Structured interview of 12 months of poison control center (PCC) inhalation cases. Follow-up measurement of pulmonary function and airway responsiveness in a subgroup with symptoms 12 to 24 h postexposure.
SETTING: A regional PCC and clinical pulmonary function laboratory.
PATIENTS: Consecutive sample of 547 inhalation cases. Interviews of 299 subjects. Lung function follow-up in 10 subjects.
MEASUREMENTS AND MAIN RESULTS: Immediate respiratory symptoms were reported by 262 (88 percent) subjects; 12 to 24 h postexposure symptoms were reported by 130 (44 percent). Cigarette smoking was significantly related to immediate onset of cough (relative risk [RR]= 1.3; 95 percent confidence interval [CI], 1.1 to 1.5); both smoking (RR = 1.6; 95 percent CI, 1.1 to 2.1) and prior asthma (RR = 1.3; 95 percent CI, 1.1to 1.6) were associated with wheeze, exhibiting multiplicative combined risk (RR = 2.8; 95 percent CI, 1.9 to 4.3). Of 10 subjects studied, none had abnormal airflow or lung volumes 8 +/- 4 days postexposure; 8 demonstrated increased airway responsiveness to methacholine. By three months, only one subject's increased responsiveness reversed; in three others, symptoms resolved but increased responsiveness remained.
CONCLUSIONS: Respiratory symptoms following irritant exposure are associated with smoking and asthma and typically resolve quickly. Continuing symptoms are associated with persistent increased airway responsiveness without other pulmonary function abnormalities. This may reflect newly induced airway changes or, alternatively, could represent underlying increased responsiveness in subjects symptomatic after irritant exposure.
University of California SF 94143-0924.
Respiratory morbidity 10 years after the Union Carbide gas leak at Bhopal: a cross sectional survey. The International Medical Commission on Bhopal.
Cullinan P, Acquilla S, Dhara VR
OBJECTIVE: To examine the role of exposure to the 1984 Bhopal gas leak in the development of persistent obstructive airways disease.
DESIGN: Cross sectional survey.
SETTING: Bhopal, India.
SUBJECTS: Random sample of 454 adults stratified by distance of residence from the Union Carbide plant.
MAIN OUTCOME MEASURES: Self reported respiratory symptoms; indices of lung function measured by simple spirometry and adjusted for age, sex, and height according to Indian derived regression equations.
RESULTS: Respiratory symptoms were significantly more common and lung function (percentage predicted forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), and FEV1/FVC ratio) was reduced among those reporting exposure to the gas leak. The frequency of symptoms fell as exposure decreased (as estimated by distance lived from the plant), and lung function measurements displayed similar trends. These findings were not wholly accounted for by confounding by smoking or literacy, a measure of socioeconomic status. Lung function measurements were consistently lower in those reporting symptoms.
CONCLUSION: Our results suggest that persistent small airways obstruction among survivors of the 1984 disaster may be attributed to gas exposure.
Department of Occupational and Environmental Medicine, Imperial College (National Heart and Lung Institute), London.