Friesen Melissa C, Davies Hugh W, Teschke Kay, Ostry Aleck S, Hertzman Clyde, Demers Paul A
School of Occupational and Environmental Hygiene, University of British Columbia, Vancouver, British Columbia, Canada.
Epidemiology. 2007 Jan;18(1):88-94. doi: 10.1097/01.ede.0000249558.18960.6b.
Exposure misclassification may occur when nonspecific exposure indicators are used. Developing estimates of more specific measures may be difficult due to sampling limitations or a paucity of historical measurements and, thus, often requires substantial effort. We examine the impact on exposure-response relationships of moving from 2 measures of exposure mixtures (dust, chlorophenols) to more specific exposure indicators (wood dust, pentachlorophenol, tetrachlorophenol) in a retrospective cohort.
The study population consisted of 26,847 male sawmill workers (> or =1 year employment between 1950 and 1995) with linkage to national cancer registries. A subcohort (n = 11,273 employed more than 1 day between 1985 and 1995) was linked to hospital discharge records. We evaluated the shape (log-linear vs log-log models), goodness of fit, precision, and expected versus observed attenuation of the exposure-response relationships.
The correlation between the cumulative exposure indices was moderately high (dust/wood dust, r = 0.68; total chlorophenol/pentachlorophenol, r = 0.88; total chlorophenol/tetrachlorophenol, r = 0.78). An increase in chronic obstructive pulmonary disease hospitalizations was found with wood dust but not with total dust. Stronger associations for non-Hodgkin lymphoma and kidney cancer incidence were observed with pentachlorophenol than with total chlorophenol; no association was observed with tetrachlorophenol. We observed greater attenuation than expected using total dust, but less than expected using total chlorophenol.
The relationships between health outcomes were substantially attenuated when nonspecific exposure indicators were used. This study demonstrates the importance of developing exposure metrics as specific to the disease-causing agent as possible, particularly when the composition of mixed exposures varies by work areas.
使用非特异性暴露指标时可能会出现暴露误分类。由于抽样限制或历史测量数据匮乏，很难得出更具体测量指标的估计值，因此通常需要付出巨大努力。我们在一项回顾性队列研究中，考察了从两种暴露混合物（粉尘、氯酚）测量指标转变为更具体的暴露指标（木尘、五氯酚、四氯酚）对暴露-反应关系的影响。
研究人群包括26,847名男性锯木厂工人（1950年至1995年期间就业≥1年），并与国家癌症登记处建立了联系。一个亚队列（n = 11,273，1985年至1995年期间工作超过1天）与医院出院记录建立了联系。我们评估了暴露-反应关系的形状（对数线性模型与对数-对数模型）、拟合优度、精度以及预期与观察到的衰减情况。
累积暴露指数之间的相关性中等偏高（粉尘/木尘，r = 0.68；总氯酚/五氯酚，r = 0.88；总氯酚/四氯酚，r = 0.78）。发现木尘会使慢性阻塞性肺疾病住院率增加，而总粉尘则不会。观察到五氯酚与非霍奇金淋巴瘤和肾癌发病率的关联比总氯酚更强；四氯酚未观察到关联。我们发现使用总粉尘时观察到的衰减比预期更大，但使用总氯酚时比预期更小。
使用非特异性暴露指标时，健康结局之间的关系会大幅减弱。本研究证明了开发尽可能针对致病因子的暴露指标的重要性，尤其是当混合暴露的成分因工作区域而异时。
