Smoking cessation among coal miners as predicted by baseline respiratory function and symptoms: a 5-year prospective study.

A prospective analysis was used to test whether respiratory impairment or the presence of respiratory symptoms predicts 5-year cigarette smoking cessation in a sample of 1,118 U.S. white, male, underground coal miners. Miners were examined in 1977 and re-examined in 1982 by NIOSH, and all miners with test abnormalities were so informed by letter. Respiratory impairment was measured by an index of airways obstruction combining the spirometric measures of Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 sec (FEV1). Bronchitis symptoms were measured by an index that combined chronic cough (3+ months/year) and chronic phlegm (3 + months/year). Among these coal miners, the presence of chronic respiratory symptoms initially was inversely associated with cigarette smoking cessation. Respiratory impairment, however, was positively associated with cigarette smoking cessation but did not reach statistical significance.