Tripepi G, Jager K J, Dekker F W, Wanner C, Zoccali C
1CNR-IBIM, Clinical Epidemiology and Physiopathology of Renal Diseases and Hypertension of Reggio Calabria, Reggio Calabria, Italy.
Kidney Int. 2007 Oct;72(7):789-91. doi: 10.1038/sj.ki.5002432. Epub 2007 Jul 25.
Epidemiological studies aim at assessing the relationship between exposures and outcomes. Clinicians are interested in knowing not only whether a link between a given exposure (e.g. smoking) and a certain outcome (e.g. myocardial infarction) is statistically significant, but also the magnitude of this relationship. The 'measures of effect' are indexes that summarize the strength of the link between exposures and outcomes and can help the clinician in taking decisions in every day clinical practice. In epidemiological studies, the effect of exposure can be measured both in relative and absolute terms. The risk ratio, the incidence rate ratio, and the odds ratio are relative measures of effect. Risk difference is an absolute measure of effect and it is calculated by subtracting the risk of the outcome in exposed individuals from that of unexposed.
流行病学研究旨在评估暴露因素与结局之间的关系。临床医生不仅想知道给定暴露因素（如吸烟）与特定结局（如心肌梗死）之间的联系在统计学上是否显著，还想了解这种关系的强度。“效应测量指标”是总结暴露因素与结局之间联系强度的指标，有助于临床医生在日常临床实践中做出决策。在流行病学研究中，暴露因素的效应可以用相对和绝对两种方式来衡量。风险比、发病率比和比值比是效应的相对测量指标。风险差是效应的绝对测量指标，通过用未暴露个体结局的风险减去暴露个体结局的风险来计算。
