Ch 1. Understanding Epidemiology Flashcards
Define epidemiology
- The study of the distribution and determinants of health or events in specified populations, and the application of this study to control health problems
Purpose of epidemiological methods.
- identify the causes of poor health
- measure the strength of associations between causes and outcomes
- evaluate interventions to improve health
- monitor changes in population health over time.
What are the main uses of epidemiology?
- Answer the 5 W’s
- identify the causes of poor health
- measure the strength of associations between causes and outcomes
- evaluate interventions to improve health
- monitor changes in population health over time.
What are some examples of health OUTCOMEs of interest?
Can be positive or negative: illness, infection, death, disability, survival.
What are the 2 factors that determine who is at risk?
Risk factors– predisposes a person to getting the outcome, like poverty.
Protective factors – less likely to get outcome, like vaccination.
What is the difference between EFFICACY and EFFECTIVENESS?
EFFICACY– how well an intervention works in a research controlled/ ideal setting
EFFECTIVENESS– how well an intervention work in the real world
What was the Doll and Hill study?
In 1950, Richard Doll and Austin Bradford Hill published a large and rigorous case-control study (Doll and Hill, 1950), which together with three other case-control studies highlighted the link between smoking and lung cancer.
What is “genetic epidemiology”
- comparing the risk of disease in groups of relatives to the risk in the GENERAL POPULATION, to identify what PROPORTION could be attributed to genetics.
- but because social settings are similar in families, focused instead on risk of disease by degree of relatedness
What is “social epidemiology”
- study the effects of the social determinants of health, such as social class, income distribution, ethnicity, gender, and discrimination
What is “health economics”
- study of financing and delivery of health services
- how access to these services affect the individual and population
- how best to use limited resources
- analyse the decision-making processes of individuals and policy-makers that may affect health outcomes
What are current challenges in epidemiology?
- environmental and lifestyle effects on pop health
- aging population
- advances in science and tech that allow for big data
- role of media
What 2 groups are epidemiological studies divided into?
- observational studies
- interventional studies
What 2 groups are epidemiological studies divided into?
- observational studies- exposure already assigned (ex: behavior, nature, circumstance)
- interventional studies- investigator assigns the exposure
What 2 groups can observational studies be divided into?
- descriptive
- analytical (always has a comparison group)
What is descriptive epidemiology?
information on the distribution of health outcomes by age, population type, geography, and/or over time
- examples of sources: birth/ death registries, adverse tx reactions, hospital records
A synonymous term for “exposure” is…
risk factor
In epidemiology, who represents the “counterfactual alternative reality”?
- counterfactual- a scenario where the exposure (risk factor) did not occur
- counterfactual group can be represented by folks that are unexposed (or did not have the risk factor)
What is causaulity?
Relating the exposure/ risk factor to the outcome.
For an association to be causal, the exposure must occur before or after the outcome?
BEFORE. Inferring causality is a complex process because there may be several risk factors that contribute in different ways to the outcome.
Causality can be broken into what 2 types of causes?
- Sufficient cause. The set of factors or conditions that can produce an outcome
- Component causes. Contribute to the outcome occurring
What is “sufficient cause”?
What makes up a “sufficient cause”?
The set of factors or conditions that can produce an outcome
- The factors that comprise the sufficient cause are called component causes, and contribute to the outcome occurring. Component causes = Contribute to the outcome occurring
What is causality?
Relating the exposure/ risk factor to the outcome.
What is a “necessary cause”?
A component cause that is essential for the outcome to occur is known as a necessary cause, for example tuberculosis cannot occur without Mycobacterium tuberculosis
What factors affect a person’s exposure?
- Environmental factors tend to affect exposure and may be physical (e.g. climate, altitude)
- biological (e.g. vectors that transmit an agent)
- structural (e.g. crowding, sanitation).
- Human factors affect both exposure and response and include age, sex, ethnicity, behaviour, genetics, and nutritional and immunological status.
