Risk factors, pulmonary function, and mortality.

Abstract

In a genetic-epidemiologic study of obstructive airway disease (OAD), cross sectional and longitudinal data (4.7 year follow-up) were collected to investigate relationships among risk factors, pulmonary function, and mortality. In the cross sectional evaluation of 2539 non-patient adults, 11 potential risk factors were found to be significantly associated with airways obstruction. Most important among these were age and smoking. Others included: demographic variables (gender, SES, education); the intake of coffee and diet soda; genetic markers (protease inhibitor "Pi" type, ABO type, ABH secretor status); and familial pulmonary disease. Examination of combinations of risk factors in cross sectional data indicated that some of these factors were important risk factors in cigarette smokers but less evident in never smokers. For example, ABO type, familial component, coffee drinking and diet soda intake were related to marked differences in lung function in cigarette smokers, but had little impact in never smokers. Thus, interactions of factors must be considered when assessing risk of pulmonary dysfunction. In the longitudinal evaluation, 11 factors found to be significant on cross sectional study plus 4 tests of lung function (closing capacity, diffusing capacity, slope of Phase III, and flow volume curves) were examined for correlations with loss of forced expiratory volume. Consistently greater declines of lung function were noted in males, older subjects, smokers, whites, and individuals carrying the type A blood group allele. Increased initial visit closing capacity was also associated with increased deterioration. Together, however, these factors accounted for only a modest amount of observed variation in decline in lung function (17% in females and 12% in males). Initial visit characteristics were not only associated with deterioration of lung function in survivors, as described above, but with survivorship per se. Age, sex, race and cigarette smoking were associated with differences in mortality. In addition to these, pulmonary dysfunction itself at initial visit was an independent risk factor for increased mortality. For example, the mortality of unobstructed males in the 5th decade of life was 16 per thousand compared to 25 per thousand in obstructed males. For females, the mortality in the 5th decade of life was 7 per thousand if unobstructed and 12 per thousand if obstructed. We conclude: 1) In cross sectional evaluation, multiple factors are associated with airways obstruction. Of these, smoking appears to interact strongly with other factors.(ABSTRACT TRUNCATED AT 400 WORDS)