CHANGES IN VENTILATORY FUNCTION IN GRAIN PROCESSING AND ANIMAL FEED WORKERS IN RELATION TO EXPOSURE TO ORGANIC DUST

OBJECTIVES - The effects of organic dust exposure on the configuration of the maximum expiratory flow volume (MEFV) curve was examined multi variately. METHODS - Data from 390 male workers in the animal feed ind ustry in The Netherlands were analyzed. A multivariate technique calle d nonlinear canonical correlation analyses was used to study the relat ionship between a set of organic dust exposure variables and a set of ventilatory function variables. RESULTS - The results indicate an almo st independent effect of the overall mean organic dust exposure and th e number of years of organic dust exposure on ventilatory function. In creasing mean organic dust exposure was associated with a decrease in both forced expiratory volume in 1 s (FEV(1.0)) and forced vital capac ity (FVC) and decreased flows at high lung volumes only. Increasing nu mber of years of dust exposure was associated with a decrease in FEV(1 .0) and a decrease in flow at all lung volumes, while the FVC seemed r elatively constant. These two distinct patterns of reduction in ventil atory function may represent two different pathological processes. Whe reas workers with prolonged exposure showed reduced values for all of the MEFV curve variables, except the FVC, those with only a few years of exposure especially showed a decrease in FVC and peak expiratory fl ow. The effect of current organic dust exposure was more evident for n onsmokers than for ex-smokers and current smokers. CONCLUSION - The ma jor finding of this study was an independent effect of overall mean or ganic dust exposure and the number of years of organic dust exposure o n the MEFV curve.