Thompson S G
Stat Med. 1983 Apr-Jun;2(2):147-53. doi: 10.1002/sim.4780020208.
Where data are collected over an extended period, in either cross-sectional or prospective studies, time trends in laboratory measurements can have misleading effects on observed associations, especially where it has not been possible to randomize the order of entry of participants to the study. In an ongoing prospective study of ischaemic heart disease, a modified cusum technique is used to examine the data for time trends. The paper considers a method for estimating where changes may have occurred, a method for adjusting for such changes in investigating the associations between variables and the appropriateness of making such adjustments.
在横断面研究或前瞻性研究中，如果数据是在较长时间内收集的，实验室测量的时间趋势可能会对观察到的关联产生误导性影响，尤其是在无法将参与者进入研究的顺序随机化的情况下。在一项正在进行的缺血性心脏病前瞻性研究中，采用了一种改良的累积和技术来检查数据的时间趋势。本文考虑了一种估计变化可能发生位置的方法、一种在研究变量之间的关联时对这种变化进行调整的方法以及进行这种调整的适当性。
