Lecture 11 - Principles of Epidemiology Lecture 10: Outline...

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Unformatted text preview: Principles of Epidemiology Lecture 10: Outline Randomized Controlled (Clinical) Trials (RCTs) Design Selecting the sample Random allocation and sources of bias Variations of RCTs Strengths and weaknesses Analysis Background Reading: Oleckno Chapter 13 Experimental Study Designs ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Hierarchy of Evidence 1. Systematic reviews / meta-analysis 2. Randomized Controlled Trials 3. Cohort Studies 4. Case Control Studies 5. Cross-sectional Studies 6. Case Report/Series Strong Inferences Weaker Inferences ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Categories of Epidemiologic Studies Epidemiologic Studies Observational Experimental Descriptive Analytic Case reports Case series Ecologic Cross-sectional Prospective cohort Retrospective cohort Case-control Randomized controlled trials Community trials ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Experimental (Intervention) Studies Most similar to the controlled experiment done by basic science researchers Similar to prospective cohort study except: investigators allocate the exposure If conducted properly, degree of confidence in the validity of the results is higher than any other epidemiologic design However, they can be vulnerable to bias if not conducted properly . ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ The First Ever Trial James Lind: 1747 Hypothesis that scurvy could be prevented by acid. Recruited 12 sailors with scurvy 2 cider 2 elixir vitriol 2 vinegar 2 sea water 2 spicy paste with barley water 2 oranges and lemons Those who received the fruit improved Vitamin C deficiency caused scurvy Repeated in 1795 on fleet of ships ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Types of Intervention Studies Randomized controlled trials Unit of analysis is the individual Local example: Reducing Deaths due to Oxidative Stress: The REDOX Study Community trials/Cluster Randomized Trial...
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Lecture 11 - Principles of Epidemiology Lecture 10: Outline...

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