EHS 260 Lecture Notes - Lecture 20: Combined Oral Contraceptive Pill, Random Assignment
18 Jun 2018
School
Department
Course
Professor
Cohort Studies
Retrospective
Prospective
Cohort Studies
Retrospective Cohort Study: Outcome and exposure occurred in the past
Example:
◦From medical records, identify a group of women who were using oral contraceptive
pills (OCPs)10 years ago and a group of women who were not using OCPs
◦Interview the women or use medical records to determine their history of heart disease
from the point of OCP use to the present
Prospective Cohort Study
◦A group of individuals is selected at random from a defined population
◦After the cohort is selected,
baseline information on potential risk factors is collected,
individuals are followed over time to track the incidence of disease between
those people subsequently exposed or not exposed to the risk factors of interest
Case Control Studies
Participants are selected based on the presence (a case) or a absence (a control) of a
disease.
Cases and controls are matched on several possible causes of disease
Comparisons of frequency of past exposure to other potential risk factors are made
between the two groups
Disadvantages
Absolute Risk – unknown
Incidence rates are not available
Group is not followed over time
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Retrospective cohort study: outcome and exposure occurred in the past. From medical records, identify a group of women who were using oral contraceptive pills (ocps)10 years ago and a group of women who were not using ocps. Interview the women or use medical records to determine their history of heart disease from the point of ocp use to the present. A group of individuals is selected at random from a defined population. Case control studies baseline information on potential risk factors is collected, individuals are followed over time to track the incidence of disease between those people subsequently exposed or not exposed to the risk factors of interest. Participants are selected based on the presence (a case) or a absence (a control) of a disease. Cases and controls are matched on several possible causes of disease. Comparisons of frequency of past exposure to other potential risk factors are made between the two groups. Difficult to obtain a good control group.
