A community study of the relation of alpha1-antitrypsin levels to obstructive lung diseases.

Since it is still uncertain whether moderate degrees of alpha1-antitrypsin deficiency predispose to the development of lung disease, data obtained from a stratified random sample of white households in Tucson, Arizona, consisting of 2586 subjects over five years of age, were analyzed. No relation was found between serum alpha1-antitrypsin levels, measured as trypsin inhibitory capacity, and ventilatory function, respiratory symptomatology, or frequency of diagnosed pulmonary diseases even among cigarette smokers. The data indicate that an intermediate level of alpha1-antitrypsin deficiency (i.e., inhibitory capacity between 20 and 62 per cent of the population's mean value) is not an important risk factor for the development of chronic obstructive lung diseases. The data militate strongly against the use of any quantitative determination of alpha1-antitrypsin as a test to identify subjects with moderate deficiency for the purpose of predicting later development of chronic respiratory disorders. The rate of severe deficiency is so low as to make population screening for such subjects impractical.