《英国医学会杂志》（BMJ）自2008年9月开始至2015年由两位流行病与统计学专家不间断地出了300多期statistical question系列。在这个系列中，两位学者每次出一道统计学选择题，进行选择并解释。现在我精选300道Statistical Question，形成中文版，请有兴趣的朋友们进行回答。BMJ 统计问题（7）:这是何种流行病学研究设计？一组研究人员决定检验以下假设：使用绝经后激素会增加患乳腺癌的风险。他们从与第一批未患乳腺癌的女性相同的社区中识别出500名新诊断为乳腺癌的女性和500名相同年龄的女性。然后，他们向所有妇女询问过绝经后激素的使用情况。
*请大家在看问题答案解析之前，先“投票”，也看看大家的结果
A group of investigators decided to testthe hypothesis that using postmenopausal hormones increases the risk of breastcancer. They identified 500 women with newly diagnosed breast cancer, and 500women of the same age, from the same neighbourhoods as the first group ofwomen, who did not have breast cancer. Then they asked all women about theirpast use of postmenopausal hormones.
What answer best describes the studydesign used here?
a) A retrospective cohort study
b) An incidence study
c) A case crossover study
d) A case-control study
Answer
d—Case-control studies gather participants together on the basis of whether they are cases with disease or controls free from disease. The question is then asked “What have these people done in the past that may have led to disease?” Retrospective cohorts by contrast follow up a group of people who have already been gathered together for some reason in the past (perhaps they attended the same school or were born in the same maternity unit). The question is then asked “What has happened to these people now?” Cohort studies may of course measure incidence. A case crossover study is a special example of a case-control study where all people are cases though the timing and degree of exposure to risk factors may vary.病例对照研究根据参与者是患病病例还是没有疾病的对照将参与者聚集在一起。然后问这个问题：“过去这些人做了什么可能导致疾病的发生？”相比之下，回顾性队列追踪了过去由于某种原因已经聚集在一起的一群人（也许他们参加了相同的活动，学校或在同一生育单位出生）。然后问这个问题：“这些人现在发生了什么？”队列研究当然可以衡量发病率。病例交叉研究是病例对照研究的一个特殊例子，尽管所有人接触风险因素的时间和程度可能有所不同，但所有人都是个案。本公众号作为医学数据分析公众号，提供一些免费医学统计学学习资源下载，欢迎点击下载。
