Cohort studies Is a type of observational and analytic study .pptx

Is a type of observational and analytic study
Is a powerful tool for examining the relationships between exposures and outcomes over time.

1. Cohort studies

2. Learning outcomes Define Cohort study Enumerate uses of Cohort study Outline the types of Cohort study List the steps of Cohort study Analyzing and reporting of Cohort study

3. Introduction Is a type of observational and analytic study Is a powerful tool for examining the relationships between exposures and outcomes over time.

4. Definition “Cohort” refers to “a group of people with defined characteristics who are followed up to determine the incidence of some specific disease, ” A cohort study observes people as two or more groups, from exposure to outcome. It begins with subjects who are free of disease /exposed and not exposed to a factor and then evaluates the subsequent occurrence of an outcome.

5. Uses Prognosis of a particular condition/disease (i.e. what likely to happen to a subject with this condition) Incidence of a particular condition/disease Measure possible cause-and-effect relationship (exposure and outcome).

6. Types of Cohort Studies Prospective cohort studies: researchers identify a group of people who do not have the outcome of interest at the beginning of the study and then follow them over time to see who develops the outcome. Retrospective cohort studies: researchers use existing data to identify a group of people who have already developed the outcome of interest and then track back in time to see who had the exposure of interest.

7. Steps to conduct Cohort study 1. Identify the study subjects; i.e. the cohort population. 2. Obtain baseline data on the exposure; measure the exposure at the start. (The exposure may be a particular event, a permanent state or a reversible state.)   3. Select a comparison group—the unexposed control cohort. 4. Follow up; measure the outcomes using records, interviews or examinations. 5. Data analysis where the outcomes are assessed and compared.

8. Reporting and critiquing of cohort studies When reporting a cohort study, it is recommended that STROBE guidance is followed. which contains a checklist of 22 items that are considered essential for reporting of observational studies. The aim is to Strengthen the Reporting of Observational studies in Epidemiology. The STROBE checklist for cohort studies - available at https://www. strobe- statement. org/ fileadmin / Strobe/ uploads/ checklists/ STROBE_ checklist_ v4_ combined. pdf-

9. Conclusion Cohort studies are a powerful tool for investigating the causes of disease and the effectiveness of interventions. They have been used to study a wide range of health issues and have provided valuable insights into the factors that affect our health.

10. References Dr. Carl M. Shy, Epidemiology 160/600 Introduction to Epidemiology for Public Health course lectures , 1994-2001, The University of North Carolina at Chapel Hill, Department of Epidemiology Rothman KJ, Greenland S. Modern Epidemiology. Second Edition. Philadelphia: Lippincott Williams and Wilkins, 1998. “How to Read a paper: The Basics of Evidence-Based Medicine” by Patricia Greenhalgh. 4th Edition, 2010 published by Wiley-Blackwell. “Epidemiology, evidence-based medicine and public health: lecture notes” by Y. Ben-Shlomo et al. 6th Edition, 2013 published by Wiley-Blackwell. Centre for Evidence Based medicine: www.cebm.net

11. Thank you Any Questions?