Chronic bronchitis in northern Sweden; a seven year follow-up.

In 1974 a prevalence survey of chronic bronchitis was performed in the Hörnefors community on individuals in the age group 20-65 years. Chronic bronchitis was diagnosed in 44 individuals giving a prevalence of 2.2% (3.4% in men and 0.9% in women). Of the individuals with chronic bronchitis 79% were men, 85% above 40 years of age, 80% smokers or ex-smokers and 75% were or had been employed at a nearby sulphite pulp factory. Alpha-1-antitrypsin deficiency phenotypes (MZ, MS, MF) were present in 11 (25% of the individuals). Spirometric obstruction was found in 12 (27%) of the individuals with chronic bronchitis. At a seven-year follow-up four of the 12 individuals with obstructive chronic bronchitis had died from chronic respiratory insufficiency, the remaining individuals still having obstructive chronic bronchitis (no information present in one individual). In individuals with simple chronic bronchitis two had developed obstruction and 12 (38%) had improved now having no respiratory symptoms. The improvement in most of them was due to termination of smoking or change of work.