Chest illnesses and the decline of FEV1 in steelworkers

This study relates the impact of various medical conditions to clinically i mportant forced expiratory volume in I second (FEV1) declines in a cohort o f steelworkers evaluated cross-sectionally and longitudinally. Medical reco rds of 1171 randomly chosen steelworkers were obtained from the medical dep artment of a steel company. We reviewed the medical records for information regarding demographic parameters, smoking status, spirometry indexes, job history, and the worker's respiratory health. These workers had performed a nnual spirometry from 1980 to 1991 at least once and wp to 12 times. We com pared the prevalence of medical conditions in 203 mat never-smoking steelwo rkers in this group of 1171 workers by separating workers into three groups on the basis of final predicted FEV1 values (<65%, between 65% and 79%, an d greater than or equal to 80%). We also evaluated the prevalence of medica l conditions and the association between these conditions and the rate of a nnual decline in FEV1 in 475; steelworkers who had at least three valid tes ts and at least 5 years separating the first and last test by multiple logi stic regression analysis. Of the 475 steelworkers, 121 were categorized as rapid decliners (an annual rate of decline in FEV1 exceeding the 75th perce ntile of the slope distribution), whereas the remaining workers served as c ontrols. Three of 203 and 17 of the remaining 200 in the cross-sectional su rvey! had final predicted FEV1 values <65% or between 65% and 79%, respecti vely. Among these 20 never-smelters, the accelerated rate of decline could be reasonably explained by factors independent of dust and age in all but t wo. In the 203 never-smokers, hay fever and trauma occurred more frequently in those with a decreased predicted FEV1. In the longitudinal study of 475 workers, the prevalence of pneumonia was significantly greater in the rapi d decliners, whereas the prevalence of allergy, asthma or hay fever, and tr auma approached a significant excess in number. Logistic regression models demonstrated that aging, weight gain, smoking trauma pneumonia, and a histo ry of allergy, asthma, or hayfever were independently related to the risk o f a clinically important decline of FEV1 in this group. In summary, there a re multiple risk factors for an accelerated rate of decline in workers with dust exposure. An accurate assessment of the causes for an excessive rate of lung function decline in an individual worker within a population requir es nn understanding of the relationship between environmental exposures, lu ng function decline, and the individual worker's underlying health. In addi tion to the three traditionally recognized variables-age, smoking, and dust exposure-the medical conditions of trauma, pneumonia, and allergy, asthma, or hayfever were related to a clinically important decline of FEV1 in this industrial population.