[Comparative investigations to the epidemiology of chronic bronchitis in Erfurt and Riga (author's transl)].

Studies concerning the prevalence of chronic bronchitis were conducted in Erfurt in 1971 and in Riga in 1974, comprising a standard interview and measurements of vital capacity and forced expiratory volume. Results in both towns are compared and critically discussed. Chronic bronchitis and obstruction are more frequent in Riga, while obstruction shows a better correlation to the severity of clinical signs in Erfurt. The influence of age, smoking, and hemoptysis are also compared; the latter showing no difference between both towns.