Week 2. Lecture 3. Guest Lecture Flashcards
What is the epidemiology?
The study of distribution and determinants of health-related events such as health, disease, and health behavior in human populations
What is the epidemiologic process?
- think of a health process
- develop a hypothesis
- design a study
- develop a protocol
- recruit people, measure exposure
- analyze data
- interpret data
What is x and y variables in the health sciences?
x=exposure and y=health outcome
What is a conceptual hypothesis?
An idea proposed by a researcher to explain the
occurrence of disease or outcome (O) with respect to an exposure (E).
What is an example of conceptual hypothesis?
Wearing glasses is associated with improvement of myopia
What is an operational hypothesis?
The testable prediction that is derived from the conceptual hypothesis
What is an example of operational hypothesis?
Teens, ages 14-19, with myopia who wear glasses 6
or more hours a day for 1 year, will have less
progression of visual acuity loss (change in 2 lines
on a vision chart) than myopic teens who do not
wear their glasses.
What is the hierarchy of designs?
- descriptive
- analytic >experimental>observational
What does a descriptive design study?
Describes only and does not examine associations
What does a analytic design study?
examines associations and tests hypothesis
What does an experimental design study?
investigator assigns exposures
What does an observational design study?
investigator observes without intervention
What is a cohort?
a clearly defined group of
individuals who are
followed together over the
same period of time.
What is the process of cohort studies?
- Begin with persons without the outcome of interest (disease free)
- Determine which of the people in the group are exposed and which are unexposed
3.Follow them over time for subsequent onset of the disease (or change in health
status)
What is true about cohort studies?
- no assignment of exposure
- no randomization
- may have follow up
- can study many outcomes/exposures
- can calculate rate of new health changes or disease
What is a special exposure cohort?
When subjects are selected to represent a specific exposure (often exposure rare).
What is a prospective study?
Subjects enrolled and followed forward into real time to measure new
health changes in follow-up.
What is a general population cohort?
When sample is selected to represent a large segment of the community with a wide range of exposures.
What is a retrospective cohort studies?
Subjects enrolled after exposure and outcome have happened. Use records to recreate past timeline of events.
What are some pros for cohort studies?
- time sequence
- ethical bc exposure already happened
- rare exposures can be studied
- multiple outcome can be studied
- exposures recorded real time
- less concern of bias in past exposure
- call collect data on mild exp/outcome
What are some cons for cohort studies?
- expensive
- years of data collection
- not good design for rare diseases
- confounding and other biases possible
What is diabetic retinopathy?
A common microvascular complication of
diabetes and a leading cause of visual impairment and blindness
What was the method for data collection?
Population based of cross sectional data. Used in-person home questionnaire-based interview of lifestyle, medical history(HRQOL).
What were the follow up methods used?
telephone call and mailed questionnaire
