At a Sheffield (England) steelworks 340 cases of frank disabling bronchitis were found between 1955 and 1961. The prevalence rate was 64 per 1,000 and the men lost 7.2 man-years in sickness- absence because of this disease per 1,000 man-years worked. Forty-seven cases started before the age of 15 years, and of the remainder 106 had an acute onset due to respiratory infection or gassing, commonly following acute bronchitis if they were over 40. Sixty-three percent of the cases started after this age, when the interval between onset and disability rapidly decreased as the onset was later. Smoking appeared to be more concerned with an insidious than an acute onset and aggravated the established disease. No evidence was found of the influence of dusty work on the disease, though work out of doors may have such an influence.
