Are respiratory decrements associated with exposure to particles including endotoxins on large California dairies?
研究了加州大型奶牛场工人暴露于颗粒物和内毒素后，跨班次肺功能是否下降，发现奶牛场工作与肺功能下降显著相关，但颗粒物和内毒素浓度本身与下降无显著关联。
<h3>Objectives</h3> To determine whether exposure to particulate matter (PM) including endotoxins on large California dairies is associated with decreased cross-shift respiratory function. <h3>Methods</h3> Male workers at 13 dairies and one control facility wore personal air samplers collecting total suspended particles (TSP) or PM2.5 over their shift. Pre- and post-shift questionnaires and pulmonary function tests were also conducted. TSP endotoxins were assessed using recombinant Factor C and GC-MS. Associations between exposure to PM and cross-shift lung function changes were assessed by regression analysis using GLM9s. <h3>Results</h3> Data from 205 dairy and 45 control facility workers were analysed. Exposure to either PM or endotoxin was significantly higher in dairy versus control workers (p<0.0001). Geometric mean dairy exposures were 793 and 35 µg/m<sup>3</sup> for TSP and PM2.5; 326 EU/m<sup>3</sup> and 0.45 picomoles/m3 for TSP endotoxin respectively. Across a shift, 29.3% and 15.6% of dairy and control workers respectively had ≥3% decrease in FEV1 while 29.6% and 13.3% of workers had similar decrements in FVC. Cross-shift pulmonary function outcomes were modelled against exposures and potential relevant factors such as smoking, age, shift length and dairy/control worker. PM2.5, TSP and endotoxin exposures were not significantly associated with changes in pulmonary function. Dairy versus control work was associated with cross-shift FEV1 regression estimates of -64 ml (p =0.02) and FVC estimates of -90 ml (p = 0.008). <h3>Conclusions</h3> Cross-shift decrements in pulmonary function were associated significantly with dairy work. However neither the concentration of PM nor endotoxin components in TSP were associated with these decrements.