谷物加工和动物饲料行业工人中与接触及选择过程相关的肺功能下降。
Decline in lung function related to exposure and selection processes among workers in the grain processing and animal feed industry.
作者信息
Post W, Heederik D, Houba R
机构信息
Department of Environmental Sciences, Wageningen Agricultural University, The Netherlands.
出版信息
Occup Environ Med. 1998 May;55(5):349-55. doi: 10.1136/oem.55.5.349.
OBJECTIVES
To follow up workers in the grain processing and animal feed industry five years after an initial survey, and to monitor exposures to organic dust and endotoxin and changes in prevalence of respiratory symptoms and lung function.
METHODS
Outcome measures in the present survey were decline in lung function over five years, rapid annual decline in forced expiratory volume in one second (FEV1) above 90 ml.s-1, and loss to follow up.
RESULTS
Among 140 workers included in the longitudinal analysis, annual decline in FEV1 and maximal mid-expiratory flow (MMEF) were significantly related to occupational exposure to dust and endotoxin in the grain processing and animal feed industry. Assuming a cumulative exposure over a working life of 40 years with an exposure of 5 mg.m-3, the estimated effect on the FEV1 would be a decline of 157 ml.s-1 (95% CI 13 to 300)--that is, about 4% of the group mean FEV1 and 473 ml.s-1 (95% CI 127 to 800) of the MMEF (about 12%). Workers with a dust exposure > 4 mg.m-3 or endotoxin concentrations > 20 ng.m-3 at the 1986-8 survey had significantly higher risk of rapid decline in FEV1 (odds ratio (OR) 3.3, 95% CI 1.02 to 10.3). The relations between occupational exposure and decline in lung function in this study occurred, despite the selection through the healthy worker effect that occurred as well. Increasing working years was related to decreasing annual decline in FEV1 and fewer people with rapid decline in FEV1 (OR 0.04, 95% CI 0 to 0.61 for over 20 v < 5 working years in the grain processing and animal feed industry). The presence of respiratory symptoms at baseline was a strong predictor of subsequent loss to follow up. Baseline lung function was not found to be predictive of subsequent loss to follow up. However, among workers lost to follow up the number of working years was more strongly negatively related to baseline lung function than among the workers who were studied longitudinally.
CONCLUSIONS
The existence of the healthy worker effect implies that an exposure-response relation in the grain processing and animal feed industry may well be underestimated. This should be taken into account when health based recommended limit values are to be developed.
目的
在首次调查五年后对谷物加工和动物饲料行业的工人进行随访，监测有机粉尘和内毒素暴露情况以及呼吸道症状患病率和肺功能的变化。
方法
本次调查的结果指标为五年间肺功能下降、一秒用力呼气量（FEV1）每年快速下降超过90 ml·s⁻¹以及失访情况。
结果
在纳入纵向分析的140名工人中，FEV1和最大呼气中期流速（MMEF）的年下降与谷物加工和动物饲料行业的职业性粉尘和内毒素暴露显著相关。假设在40年的工作寿命中累积暴露量为5 mg·m⁻³，估计对FEV1的影响将是下降157 ml·s⁻¹（95%可信区间13至300），即约为该组平均FEV1的4%；对MMEF的影响将是下降473 ml·s⁻¹（95%可信区间127至800），约为12%。在1986 - 1988年调查中粉尘暴露>4 mg·m⁻³或内毒素浓度>20 ng·m⁻³的工人，FEV1快速下降的风险显著更高（优势比（OR）3.3，95%可信区间1.02至10.3）。尽管存在健康工人效应导致的选择偏倚，但本研究中职业暴露与肺功能下降之间的关系依然存在。工作年限增加与FEV1年下降减少以及FEV1快速下降的人数减少相关（在谷物加工和动物饲料行业中，工作超过20年与工作<5年相比，OR为0.04，95%可信区间0至0.61）。基线时存在呼吸道症状是后续失访的有力预测因素。未发现基线肺功能可预测后续失访情况。然而，在失访工人中，工作年限与基线肺功能的负相关程度比纵向研究的工人更强。
结论
健康工人效应的存在意味着谷物加工和动物饲料行业的暴露 - 反应关系很可能被低估。在制定基于健康的推荐限值时应考虑到这一点。
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