The changing face of chronic bronchitis with airways obstruction.

A total of 178 patients with obstructive airways disease were studied between 1966 and 1972, a period which followed a substantial fall in atmospheric pollution in Sheffield. Compared with patients from an earlier study of the same age and smoking habits they had less productive cough, fewer winter illnesses, less severe breathlessness, and only one-third of the rate of decline of forced expiratory volume (FEV). The analysis of the change in the annual loss of FEV was complicated. There were virtually no sudden steep falls of respiratory function, and patients with very low values of FEV survived for long periods. The predominant cause of death was cor pulmonale.Chronic hypoxia may be more of a problem in the next few years than bronchial infection. I believe that the clean air policy has effected an improvement and that the nature of chronic bronchitis with severe obstructive airways disease is changing, but further studies will be needed to confirm this.