VARIABILITY OF EXPOSURE MEASUREMENTS IN ENVIRONMENTAL EPIDEMIOLOGY
VARIABILITY OF EXPOSURE MEASUREMENTS IN ENVIRONMENTAL EPIDEMIOLOGY
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DOI：
10.1093/oxfordjournals.aje.a114606
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发表时间：
1987-05-01
影响因子：
5
通讯作者：
CLAUSING, P
中科院分区：
文献类型：
--
作者：
BRUNEKREEF, B;NOY, D;CLAUSING, P
在环境流行病学研究中，接触有害物质在时间和空间上往往是高度可变的。通常情况下，不可能直接测量研究对象对这些制剂的相关个人暴露。取而代之的是，在许多情况下，在固定的地点和/或在有限的时间段内进行曝光测量。从某种意义上说，这种测量方法并不完美，因为它们只是近似于研究对象的“真实”个人暴露。当暴露的测量在时间和空间上变化很大时，单次测量仅在有限的范围内接近真实暴露。可以通过在时间和空间上重复测量来研究暴露测量的可变性。方差分析技术可用于将受试者内部或“错误”的方差与受试者之间或真实的方差分开。计算误差方差与真实方差之间的比率对于评估使用这些暴露测量计算的相关系数和回归系数的潜在偏差是一项有用的技术。使用来自多项不同研究的数据，作者估计了铅暴露和二氧化氮暴露变量的变异率。结果表明，这些比率可能很大。给出了不同铅暴露变量对儿童血铅水平回归系数偏差的经验例证。建议更常规地进行试点研究，以估计环境流行病学研究中感兴趣的暴露变量的变异率的大小。
In studies in environmental epidemiology, exposure to harmful agents is often highly variable in time and space. It is not usually possible to measure the relevant, personal exposure of study subjects to these agents directly. Instead, exposure measurements are performed at fixed sites and/or for limited periods of time in many cases. Such measurements are imperfect in the sense that they only approximate the "true" personal exposure of study subjects. When measures of exposure are highly variable in time and space, single measurements approximate the true exposure only to a limited extent. The variability of measures of exposure can be investigated by repetition of the measurements in time and space. Analysis of variance techniques can be used to separate the within-subject or "error" variance from the between-subjects or true variance. Computation of the ratio between the error variance and the true variance is a useful technique to evaluate the potential bias in correlation and regression coefficients calculated with these measures of exposure. Using data from a number of different studies, the authors have estimated the variance ratio of lead exposure and nitrogen dioxide exposure variables. The results suggest that these ratios may be large. Empirical illustrations are given of bias in regression coefficients of childhod blood levels on different lead exposure variables. It is recommended that pilot studies be performed more routinely to estimate the magnitude of the variance ratios of exposure variables of interest in studies in environmental epidemiology.