An overview of cohort study designs and their advantages and disadvantages

Background: Cohort studies are analytical observational research studies which follow groups (cohorts) of subjects forward in time from an exposure to an outcome/s. Rigorous cohort studies provide the best scientific evidence of all the observational research designs. Contents: This paper provides an overview of the definition, design, analysis, interpretation, advantages and disadvantages of cohort studies. Readers should appreciate the strengths, weaknesses and potential pitfalls of cohort studies when interpreting and applying results to clinical practice. Conclusions: Cohort study designs should be considered when RCT are not possible or practical for ethical, logistical, or financial reasons. When properly designed and interpreted, links between exposures and outcomes (including an indication of causality) can be made.