Stewart Patricia A, Lees Peter S J, Correa Adolfo, Breysse Patrick, Gail Mitchell, Graubard Barry I
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, 6120 Executive Boulevard, MSC 7240, Rockville, MD 20892-7240, USA.
Ann Occup Hyg. 2003 Jul;47(5):399-411. doi: 10.1093/annhyg/meg060.
To evaluate three methods for assessing retrospective exposures of acrylonitrile workers.
Three methods used to develop historical exposure estimates for a retrospective cohort mortality study of acrylonitrile workers were considered. The first method was deterministic, incorporating estimates of the impact of changes that took place in the workplace. The second method used the ratio of the mean of the measurements for three similar jobs to estimate a fourth similar job. The third method was based on the development of homogeneous exposure groups (HEG). Estimates of acrylonitrile exposure were developed using these three methods and compared with measurement means (observed means) across three categories of airborne exposure concentrations (<0.5, 0.5-0.99 and >or=1 p.p.m.) and three categories based on the number of measurements used to develop the estimate (<10, 10-29 and >or=30).
The correlation between the estimates and the observed values was about 0.65 for all three methods. Estimates using the deterministic method tended to overestimate the observed means by 17%, but the number of estimates was not above or below the observed means more often than expected. There was no statistically significant relationship between the exposure estimates and the acrylonitrile concentration in the air or the number of measurements used to develop the estimates. The estimates averaged within 60% of the observed means when concentrations were above 0.5 p.p.m. and 25% regardless of the number of measurements on which the estimates were based. Estimates from the ratio method were randomly distributed above and below the observed means and averaged 70% above the observed means. The air concentration did not affect the performance of the method, although above 1 p.p.m. the estimates were within 40% of the observed means. The number of measurements comprising the estimates was related on a relative scale to the performance of the method. Exposure estimates using the HEG method were neither greater nor less than the observed means more often than what was expected. The method did better as concentration and the number of measurements increased. The estimates were within 60% of the means at >0.5 p.p.m. and for all measurement categories. Overall, there was no statistically significant difference between the estimates derived from the three estimation methods.
All methods performed reasonably well, but the deterministic and HEG methods appeared to develop estimates closer to the observed means for concentrations >0.5 p.p.m., regardless of the number of measurements.
评估三种用于评估丙烯腈工人回顾性暴露情况的方法。
考虑了三种用于对丙烯腈工人回顾性队列死亡率研究进行历史暴露估计的方法。第一种方法是确定性的，纳入了对工作场所发生变化影响的估计。第二种方法使用三个类似工作的测量均值之比来估计第四个类似工作。第三种方法基于同质暴露组（HEG）的建立。使用这三种方法得出丙烯腈暴露估计值，并与三类空气传播暴露浓度（<0.5、0.5 - 0.99和≥1 ppm）以及基于用于得出估计值的测量次数的三类情况（<10、10 - 29和≥30）下的测量均值（观察到的均值）进行比较。
三种方法的估计值与观察值之间的相关性均约为0.65。使用确定性方法得出的估计值往往比观察到的均值高估17%，但估计值高于或低于观察到的均值的次数并不比预期更频繁。暴露估计值与空气中丙烯腈浓度或用于得出估计值的测量次数之间没有统计学上的显著关系。当浓度高于0.5 ppm时，估计值平均在观察到的均值的60%以内，且无论估计值所基于的测量次数如何，均为25%。比值法得出的估计值在观察到的均值上下随机分布，平均比观察到的均值高70%。空气浓度不影响该方法的性能，尽管在浓度高于1 ppm时，估计值在观察到的均值的40%以内。构成估计值的测量次数在相对尺度上与该方法的性能相关。使用HEG方法得出的暴露估计值高于或低于观察到的均值的次数并不比预期更频繁。随着浓度和测量次数的增加，该方法表现更好。在浓度>0.5 ppm时以及对于所有测量类别，估计值在均值的60%以内。总体而言，三种估计方法得出的估计值之间没有统计学上的显著差异。
所有方法表现都较为良好，但确定性方法和HEG方法在浓度>0.5 ppm时似乎能得出更接近观察到的均值的估计值，无论测量次数如何。
