Respiratory symptoms and ventilatory capacity in soy bean workers.

Respiratory function was studied in a group of 29 soy workers exposed to soy bean dust produced after extraction of soy oil. The prevalence of all chronic respiratory symptoms was consistently higher in exposed than in control workers, although the differences were not statistically significant. During the Monday work shift there was a significant mean acute across-shift decrease in maximum expiratory flow rates at 50% and 25% vital capacity (FEF50: -6.4%; FEF25: -12.4%). Changes in vital capacity (FVC: -3.6%) and 1-sec forced expiratory volume (FEV1: -2.7%) were smaller, but still statistically significant. There were also statistically significant acute reductions in all ventilatory capacity parameters over the work shift on the following Friday, although the changes were in general smaller than on Monday (except for FEV1). An analysis of Monday preshift values of ventilatory capacity in soy bean workers suggests that exposure to soy bean dust may lead to chronic respiratory impairment in some workers.