Diminished pulmonary function in long-term workers exposed to cotton dust determined in a cross-sectional study in small Pakistani enterprises
研究对比了巴基斯坦大型棉厂和小型织布厂工人的肺功能，发现小型织布厂工人随工作年限增加肺功能下降和呼吸道症状风险升高，而大型工厂未发现类似效应。
PURPOSE: While large cotton industry plants producing for the foreign market have undergone improvements of occupational hygiene lately, working conditions in power looms producing mainly for the local market are still poor. The respiratory health in workers of power looms has not been studied so far. METHODS: In a cross-sectional study, 51 male cotton workers from power looms, 58 from large cotton factories and 52 controls were investigated by spirometry and a symptoms questionnaire. Spirometric measurements and respiratory symptoms were related to exposure duration in large and small factories by multivariate linear regression and logistic regression, respectively, with smoking, age and anthropometric parameters considered as confounders. RESULTS: Work duration in power looms was associated with declines in forced expiratory volume in 1 s, peak flow, maximum midexpiratory flow and forced expiratory flow 75 and an increased risk of obstruction (OR 1.09/year; 95% CI: 1.002 to 1.18) by applying the Global Lung Initiative equations. Except cough that was only associated with smoking, all respiratory symptoms (chest tightness, shortness of breath, fever) increased as a function of duration of exposure in power looms but not in large factories. CONCLUSIONS: Despite limitations inherent in the cross-sectional approach, there is evidence for workers in small weaving factories to face an increased risk of pulmonary function loss and respiratory symptoms. Industrial hygiene measures in these small enterprises should be encouraged. Failure to detect adverse respiratory outcomes from occupation in large factories could be due to a 'survivor' (healthy worker) effect.