Studies of the Familial Aggregation of Chronic Bronchitis and Obstructive Airways Disease

Abstract

The familial aggregation of chronic branehitis and obstructive airways disease was investigated in a propositus population of 430 persons aged 45–54 years and 1340 of their first (1°), second (2°) and third (3°) order relatives. All subjects were screened in their homes using a modified British MRC respiratory disease questionnaire and a portable spirometer. 1° relatives of propositi with either chronic bronchitis or obstructive airways disease demonstrated up to a two-fold excess prevalence of chronic bronchitis when compared to 1° relatives of non-effected propositi. This excess prevalence of chronic bronchitis was independent of sex, cigarette smoking patterns, respiratory illness history, residence in a common household, geographical distribution within the study community and the presence of α₁-antitrypsin Pi variants. The prevalence of chronic bronchitis in 1° relatives of diseased propositi was also greater than in 2° relatives of diseased propositi, In whom the prevalence approximated that of the general population.