流行病学英文讨论课题目.pptVIP

Discussion Xin Huang School of public health, Central South University In 1993 a case control study was conducted to assess a possible association between serving in the Gulf War in 1991 and the subsequent diagnosis of neurological diseases. Researchers compared the military records of 750 Army soldiers seen for neurological symptoms at Walter Reed Army Hospital in 1992 to 1500 Army soldiers seen at Walter Reed Hospital the same year for non-neurological symptoms. In late 1991 and 1992 Army officials were concerned about the health of soldiers who served in the Gulf War. They were therefore more likely to refer soldiers with neurologic symptoms who had served in the Gulf War to Walter Reed Hospital vs. Army soldiers with similar symptoms who had not served in the Gulf War. The researchers used military records, which were accurately maintained by unit leaders, not the subjects themselves, to establish if each subject did or did not serve in the Gulf War. The study concluded that Army soldiers who served in the Gulf War had 50% more risk of having subsequent neurological disease vs. those who did not serve in the Gulf War. Subsequent analyses showed that the investigators often failed to identify subjects with mild neurological diseases among those who did not serve in the Gulf War. How might this have affected the risk estimates? Choose the best answer. A.) It would have biased the estimate towards the null value of 1.0. B.) It would have biased the estimate away from the null value of 1.0. C.) It would have affected the study’s external validity but not its internal validity. D.) The effect cannot be reasonably determined based on the information provided. E.) It would have resulted in non-differential misclassification of exposure status. 研究者在一个人口为10万人的社区中开展口腔鳞癌的研究。首先研究人员对所有的社区人群进行了口腔粘膜白斑的筛查试验，发现有2000人呈现阳性结果。此后研究者对筛查阳性的患者进行了组织活检，并进行了病理学检查，最后100人确诊为口腔鳞癌患者。 通过以下研究能否得知该社区人群口腔鳞癌的患病率？为什么？ 如何分析吸烟与口腔鳞癌之间有无关联，请列出分析表格，并计算和解释关强度 该研究者怀疑吸烟可能为该疾病的病因，因此他将此100名确诊的患者作为病例，同时每位确诊