[A prospective study on respiratory symptoms and functions in new employees exposed to cotton dust]

Sixty new employees in a cotton textile mill were followed up for five years to study their occurrence of byssinosis and its natural history. Results showed that the workers complained more cough, expectoration and other respiratory irritation symptoms at their early exposure to cotton dust, and the frequency of chest tightness in them reached the peak one year after exposure and remained at higher level later. Stratified analysis showed that all the respiratory symptoms did not correlate with their smoking habits, specific body constitution, etc. Forced expiratory volume at one second (FEV1) after shift declined with length of exposure and appeared a tendency to exacerbate gradually, especially in workers with a positive skin test of cotton antigen. Smoking had no influence on it. It suggests that exposure to cotton dust and idiosyncracy of the workers play important roles in damage to lung function.