Impaired pulmonary function as a risk factor for mortality.

Prospective follow-up information obtained between 1976 and 1981 on mortality among 2539 individuals showed that pulmonary function impairment is a risk factor for short-term mortality, even when risk factors such as age, sex, and smoking are considered. Predicted risk curves for impaired individuals (those with forced expiratory volume in one second less than 68% of forced vital capacity) are consistently higher among all race-sex categories over all ages. Survival analysis using the proportional hazards model shows a steeper decline in estimated survival among individuals with poor pulmonary function compared to those with good pulmonary function, adjusted for age, race, and smoking effects. These observations are consistent with the concept that impairment of pulmonary function is a risk factor for morbidity and mortality from several nonrespiratory as well as respiratory diseases and that it acts by contributing to various pathogenic mechanisms in different organ systems.