Institute for Risk Assessment Sciences, Division Environmental Epidemiology, Utrecht University, 3508 TD, Utrecht, The Netherlands.
Occup Environ Med. 2010 Sep;67(9):636-8. doi: 10.1136/oem.2009.053421.
In occupational epidemiology, differences in the temporal coverage of the exposure history by available exposure measurement data may affect the uncertainty of exposure estimates. In the reporting of results of studies, greater attention should be paid to the extent to which exposure assessments require extrapolation outside the timeframe for which exposure measurements are available. We propose a simple graphical method that can be used to visualise the temporal coverage of exposure history with exposure measurements and the extent of temporal extrapolation needed.
We construct a graph that displays the accumulated work history years for which exposure had to be assessed in each calendar year. Years for which exposure measurements were available are shaded. The proportion of work history years covered by exposure measurements and the proportion of work history years accrued before the first measurements are summarised. When available, the actual number of measurements available in each calendar year is shown.
We demonstrate the application of the graphical tool in three nested case-control studies that reported on leukaemia in relation to low-level benzene exposures in the petroleum industry. Considerable differences in temporal coverage between the studies were illustrated, which may have resulted in differences in the reliability of the retrospective exposure estimates derived for these studies.
We introduce a graphical tool for visualising the temporal coverage by available exposure measurement data in epidemiological studies and encourage others to use similar graphs to derive and share better qualitative insights into the uncertainty in exposure assessment.
在职业流行病学中，可用暴露测量数据记录的暴露史的时间覆盖范围的差异可能会影响暴露估计的不确定性。在研究结果的报告中，应更加关注暴露评估在多大程度上需要在可获得暴露测量数据的时间范围之外进行外推。我们提出了一种简单的图形方法，可用于直观地显示暴露测量记录的暴露史的时间覆盖范围以及需要的时间外推程度。
我们构建了一个图形，显示了在每个日历年内必须评估暴露的累计工作年限。有暴露测量数据的年份用阴影表示。总结了暴露测量记录覆盖的工作年限比例和在首次测量之前累积的工作年限比例。当可用时，还显示了每个日历年内实际可用的测量次数。
我们在三个嵌套病例对照研究中演示了图形工具的应用，这些研究报告了石油行业中低水平苯暴露与白血病之间的关系。这些研究之间在时间覆盖范围上存在明显差异，这可能导致这些研究中得出的回顾性暴露估计的可靠性存在差异。
我们引入了一种用于在流行病学研究中直观显示可用暴露测量数据的时间覆盖范围的图形工具，并鼓励其他人使用类似的图形来更好地定性地了解暴露评估的不确定性。
