Alpha-1-Antitrypsin Types and Chronic Obstructive Lung Disease in an Industrial Community in Northern Sweden

In a community in Västerbotten county in northern Sweden occupationally dominated by a sulphite pulp factory all individuals (n = 3,466) received a questionnaire concerning respiratory symptoms, 94.0% answered and 8.1% claimed to have symptoms indicative of chronic obstructive lung disease (COLD). Of these individuals 93% were examined clinically, and the relationships between respiratory symptoms, verified COLD, smoking, occupation and quantitative and qualitative variations in the α1-antitrypsin (α1-AT) system (Pi) were examined. The frequency of all rare Pi types together was increased among individuals with COLD compared to a sample of individuals without respiratory symptoms and to the population. In individuals with COLD the frequencies of the MS, MZ and MF types taken separately were significantly increased when compared to the population. There were no significant differences in Pi frequencies between patients with chronic bronchitis and bronchial asthma, nor between sulphite pulp workers with COLD and other patients with COLD. Among individuals with respiratory symptoms chronic bronchitis was found to be correlated with occupation at the sulphite pulp factory, smoking and rare Pi types, the correlation coefficients being 0.42, 0.34 and 0.14, respectively. The M subtypes showed no association with COLD. Quantitative α1-AT differences between individuals with COLD and individuals without respiratory symptoms were found only in the M1M2 type. Low α1-AT levels (below (–)2 SD units) among M type individuals as a whole were not associated with COLD.