COTTON DUST AND ACROSS-SHIFT CHANGE IN FEV(1) AS PREDICTORS OF ANNUAL CHANGE IN FEV(1)

In this report of a 5-yr longitudinal study of workers employed at six cotton textile mills, exposure and across-shift FEV(1) change were evaluated as possible predictors of the annual change in FEV(1) for yam manufacturing workers. A total of 611 workers had three repeatable spirometric tests, over at least 3 yr, and at least one (average of three) across-shift test, while always working the same shift. The ''same shift'' criterion controlled for the effect of diurnal variation. Average exposure was determined from measures of lint-free elutriated cotton dust in combination with job histories. This study found a significant association between the acute and chronic effects of cotton dust exposure. Both exposure and across-shift change proved to be significant predictors of annual change, and excess annual declines in FEV(1) were predicted even for exposures of 200 mu g/m(3) and across-shift drops in FEV(1) of 200 ml. These results suggest that, to prevent dust-related chronic decline in lung function, current smokers should be excluded from yam manufacturing work and exposures should be reduced below 200 mu g/m(3), to approximately 100 mu g/m(3).