[Monitoring of pulmonary ventilation function and respiratory symptoms in cotton-processing workers]

A follow-up study in cotton workers (35 female and 31 male) was performed ten years after the original cross-sectional study. The prevalence of byssinosis considerably increased during the follow-up study in female (22.9%; 42.9%) and in male (25.8%; 51.6%) workers. Similarly, the prevalence of almost all respiratory symptoms was significantly higher during the follow-up study than at the time of the initial study. Significant acute reductions of FVC and FEV1 during the work shift were recorded in both surveys. The mean annual decline in ventilatory capacity was greater than expected for both female (FVC: -0.036 L/year; FEV1: -0.059 L/year) and male workers (FVC: -0.059 L/year; FEV1: -0.068 L/year). The mean total airborne dust concentration was 3.95 mg/m3 with an average respirable dust concentration of 0.97 mg/m3. Our study demonstrated an association between exposure to cotton dust and increasing prevalence of respiratory symptoms and progressive impairment of ventilatory capacity.