Epidemiologic study of clinical and physiologic parameters in grain handlers of northern United States.

To study the effects of grain dust exposure, we compared respiratory parameters between 310 grain handlers and 237 city workers of comparable age, height, weight, and smoking habits. Both populations resided and worked in the same geographic area of the United States. Information was obtained by questionnaire, interview, and examination. Pulmonary function tests included FEV1, FVC, FEF25-75, Vmax50, CV, delta N2/L, and DLCO. The prevalence of acute work-related and chronic respiratory symptoms, of auscultatory bronchi, and of airways obstruction (FEV1/FVC less than 0.7) were significantly higher (p less than 0.05) in grain handlers than in control subjects. The mean values of all lung functions except CV, delta N2/L, and DLCO were significantly lower in grain workers than in control subjects. The effects of smoking and grain handling on symptom prevalence and lung functions adjusted for age and height, analyzed by logistic regression model, were highly significant (p values ranged from 0.00001 to 0.5) and independent. The odds of having chronic bronchitis or wheezing at work were, respectively, increased 4.4-fold and 4.8-fold by grain handling and by 2.9-fold and 1.9-fold by smoking. Grain handling increased the odds of having airways obstruction 2.6-fold and smoking increased it 2.7-fold. We conclude that grain handlers have a higher prevalence of chronic bronchitis and other respiratory symptoms than do comparable workers who do not handle grain. The effect of grain dust exposure on symptom prevalence is usually greater than that of smoking. Grain handling has an adverse effect on lung function that is of the same or smaller magnitude than that of smoking.(ABSTRACT TRUNCATED AT 250 WORDS)