Cohort Study

Cohort study ●​ Cohort=same alikeness ●​ Follow up ●​ Two main types ○​ Prospective ■​ Using data that I have retrieved from this study ■​ No other data were given beforehand ○​ Retrospective ■​ Using data that was given beforehand Aspect Prospective Cohort Retrospective Cohort Timeframe Follows participants into the future Existing records from the past. Also follow them continuously Exposure Measured at the start, before outcomes occur Measured from past records Outcome Occurs after enrollment Outcome may have already occurred Example Physical activity & diabetes Asbestos exposure & lung cancer Prospective Cohort study Physical activity and risk of T2 Diabetes: 10 Year cohort study Participants Participants are chosen before developing on diabetes (outcome), they are followed through the study These participants does not have diabetes yet, but are at risk group Exposure With self reported physical activity baseline… ●​ High ●​ Moderate (60~150 min) ●​ Low(less than hour) Follow up 10 years study Annual health assessments are done and questionnaires were given out to identify T2 diabetes Retrospective Cohort Study Occupational Asbestos Exposure and lung cancer risk Evaluate how would past exposure on asbestos will associate with lung cancer Population 2,000 factory workers in 1970-1990 Ontario. This group would have been exposed to asbestos Exposure Historical job records, environmental assessments Followup Lung cancer incidence tracked from 1990 onward (using health records) Here we have already had data of workers at risk by exposure to asbestos.