We recruited 985 patients with COPD but without hypoxemia or other serious disease, treated them in a standard fashion, and followed them closely for nearly 3 yr. At the time of recruitment the patients were carefully characterized as to symptom severity, lung function, exercise tolerance, and quality of life, and studies of lung function were repeated during follow-up. Overall mortality was 23% in 3 yr of follow-up. Patient age and the initial value of the FEV1 were the most accurate predictors of death; when FEV1 before bronchodilator was used, the response to bronchodilators was directly related to survival, but this relationship became nonsignificant when postbronchodilator FEV1 was used as a primary predictor. After adjustment for age and FEV1, mortality was related positively to TLC, resting heart rate, and perceived physical disability, and related negatively to exercise tolerance. These relationships, though significant, were relatively weak. When standardized for age and FEV1, mortality in the present series was less than that of a previous series (4), and the same as that of hypoxemic patients with COPD who received continuous home O2 therapy. Changes in FEV1 with time averaged -44 ml/yr, but the standard deviation was large. Patients with low initial values of FEV1 showed relatively little further decline, probably indicating a survivor effect. In patients with well-preserved initial FEV1, rate of decline correlated negatively with bronchodilator response, symptomatic wheezing, and psychological disturbances.

To assess the risk of chronic obstructive pulmonary disease symptoms due to long-term exposure to ambient levels of total oxidants and nitrogen dioxide (NO2), symptoms were ascertained using the National Heart, Lung, and Blood Institute (NHLBI) respiratory symptoms questionnaire. A total of 7,445 Seventh-day Adventist (SDA) nonsmokers who were 25 yr of age or older and had resided at least 11 yr in areas of California with high to low photochemical air pollution were included in this study. Cumulative exposures to each pollutant in excess of four thresholds were estimated for each participant, using zip codes for months of residence and interpolated dosages from state air-monitoring stations. Multiple logistic regression analyses were conducted individually and together for pollutants and included eight covariables, including passive smoking. A statistically significant association with chronic symptoms was seen for total oxidants above 10 pphm (196 mcg/m3) (p less than .004, relative risk of 1.20 for 750 hr/yr). Chronic respiratory disease symptoms were not associated with relatively low NO2 exposure levels in this population. When these pollutant exposures were studied with exposures to total suspended particulates (TSP) and sulfur dioxide (SO2), only TSP exposure above 200 mcg/m3 showed statistical significance (p less than .01). Exposure to TSP is either more strongly associated with symptoms of chronic obstructive pulmonary disease than the other measured exposures or is the best single surrogate representing the mix of pollutants present.

No abstract