流行病学英文课件.ppt

Case-Control Studies Introduction Matching Investigate Example Design of Case-Control Studies Data collection and analysis Bias Strengths and Weaknesses Several important features Introduction Historical Perspective Definition Types of Design Unique contribution of epidemiology to the repertoire of clinical research designs First case-control study performed in late 1950s Doll and Hill’s study of lung cancer and smoking behavior among physicians Jerome Cornfield’s classic description of “Retrospective Studies” New statistical tools were developed to analyze the study design - logistic regression Definition A case-control study is a design in which individuals with an event or condition of interest, CASES, are identified and then compared with regard to one or more exposures to individuals without the event or condition of interest, CONTROLS. Case-control investigations typically are designed to assess the association between occurrence of disease and an exposure suspected of causing (or preventing) that disease. Types Family of epidemiological study designs Traditional case-control design Case-control studies within cohorts Nested case-control study design Case-cohort study design Case-parent study design Case-only study design Matching Summarize Types Problems with Matching  Matching is defined as the process of selecting controls so that they resemble the cases with regard to certain characteristics The goal of matching is to create similar distributions between cases and controls with regard to certain characteristics Matching can be used to Adjust for potential confounding factors Increase precision of estimate Individual level matching For each case in the study, one or more controls are selected with identical (similar) characteristics as the case Frequency, or group, matching Select controls so that the proportion with a certain characteristic is identical to the proportion of cases with that characteristic  Difficult and expensive Cannot evaluate th