Analysis is presented of the relationship between decline in ventilatory function and possible symptoms of bronchial hypereactivity. Data comes from three consecutive surveys within a 13-year follow-up study of a population sample of 1747 persons (718 males and 1029 females) who completed spirometric testing and interviews. Chest symptoms recorded in the two initial surveys were used as baselines for the prognostic study on FEV
1 change. To evaluate changes in lung function the FEV
1 decline index, expressed as percentage of FEV
1 loss during the study period, was calculated. Chronic wheezing and asthma-like attacks were very strongly related to FEV
1 baseline level. Multiple linear regression analysis for each separate symptom including age and smoking habits as confounders and showed that the FEV
1 decline index was higher and more significant when wheezing and asthma-like attacks or chronic cough were present. When the combination of symptoms were introduced into the regression model, the effect of wheezing became insignificant. Only attacks of shortness of breath in both sexes and chronic cough in women were significantly associated with more rapid FEV
1 decline. However, the effect of persistent wheezing in men had a rather substantial impact on FEV
1 change. Comparing the effect of the number of cigarettes smoked with the effect of symptoms, one can see that FEV
1 decline due to attacks of shortness of breath is comparable to that seen with heavy smoking. There was no strong evidence that the symptoms under study precede the more rapid FEV
1 decline.
Key words Lung function decline - Chronic wheezing - Asthma-like attacks - Prospective study