the study of the distribution of disease and determinants of disease frequency in populations
epidemiology
*it is the study of the CAUSES of disease
what is the goal of epidemiology?
to control health problems and imporve health at the population level
what is operationally in reference to epidemiology?
- “counting” the causes of morbidity and mortality
- determining variables associated with causes of morbidity and mortality
- IDing factors that are “causes” and are POTENTIALLY MODIFIABLE
- guiding (and evaluating) interventions to improve public health
what are the concerns of epidemiolgy?
that we measure both exposure and outcome accurately and understand what population is represented
what is an endemic
the usual occurence of a disease in a given populaiton
what is an epidemic?
a meaningful inc in the occurence of a disease in a given population
what is a pandemic?
spread of a disease across a large region or worldwide
what is the independent variable?
exposure of interest
what is the dependent variable?
outcome of interest
epidemiology is fundamentally concerned with what?
populations
association is what?
an identifiable RELATION btw an exposure and a disease
what are the 3 questions in a causal inference?
- methodical question (how do we look for a cause)
- ontological question (what is a cause)
- ethical question (how do we decide if there is enough evidence to act on a cause)
what is the cause of a disease?
an event, condition, or characteristic that PRECEEDED the disease and without which the disease WOULD NOT have occurred at all or would not have occurred until some later time
what is the criteria for assessing causality?
strength of the association dose-response relationship temporal sequence biologic credibility consistency of findinga across studies
what is the dose-response relationship?
does risk inc with inc exposure?
what does temporal sequence mean?
does the exposure precede the disease?
what is biologic credibility?
is there a known biologic basis for the relationship?
*depends on current state of knowledge
what is consistency of findings?
do multiple studies report similar findings regarding the E->D relationship?
**studies can differ by investigator, methodology, and study population
what is the epidemiologic approach?
- ID a DISEASE of interest
- ID EXPOSURES of interest “risk factors”
- statistical associations btw exp./disease
- hold constant factors that may be “mixed up” in this measure of association
- infer a causal association
- recommend intervention
what is a risk factor?
a factor which if present inc the probablilty of a disease occurence
- exposure must precede disease onset
- must be associated with an inc disease frequency
- absence of error and bias
what are the 4 types of scales to quantify epidemiology?
- nominal scale
- ordinal scale
- interval scale
- ratio scale
scale that uses names
nominal
scale that follows an order based on severity
ordinal
scale that follows a mathematical order but has no true zero
interval
