Exam 1 Flashcards
Epi Def
Study of distribution and determinants of health related events in specified populations and the application of the study to control health issues
fundamental question of epi
does an exposure cause an outcome?
3 data types
Describe, Predict and Causal Inference
Possible Exposure-disease relationships
limited evidence (unworthy of study), good evidence (worthy of a study), strong evidence (basis of public policy)
4 explanations of association
causal, reverse causation, chance, bias
web of causation
causation due to many interconnected factors
Pro: multiple causes to a disease, links bio to social determinants
Critiscism of web of causality
lack of causal mechanisms, lack of origins, no theory, no difference between individual and population determinants
Biomedical model criticism
focus on biological determinants, social determinants are secondary, populations are sums of individuals
Hills causal criteria
9 total: experimental, temporal, strength of association, dose response, biological plausibility, consistency, analogy, specificity, coherence
Temporal Relationship
Exposure preceding an outcome
Strength of association
Stronger associations are more likely to be causal
Dose Response
Greater exposure = greater outcome
biological plausibility
reasonable proposed bio mech
consistency
observe association within different contexts but get same results
analogy
similar to other established causal relasionships
specificity
uniqueness of given exposure with a specific outcome
Coherence
Similar to results in a lab
Modified Determinism
component, necessary and sufficient causes
Sufficient cause
a single cause or set of causes that are necessary and make the disease occur
component
a factor needed in some cases
necessary
a factor found in all cases
Pros and cons of modified determinism
Pro: conceptual, bio makes sense, see patterns of risk factors
Cons: we don’t know all causes, not quantitative
Susser’s Pragmatic Causal Criteria
association - factor must occur together with Y
Time order - X must precede Y
Direction - X causes Y but Y doesn’t cause X
How to evaluate causal direction
consistency, strength, specificity, predictive performance, coherence
Etiologic Factors
biologic understanding of how cause of disease leads to structural and physiological changes that result in disease
Are all etiologic factors risk factors?
YES but not all risk factors are etiologic
Primary Prevention
To prevent initial development of disease in disease free individuals
Secondary Prevention
Early detection of existing disease in asymptomatic individuals
Diagnosis
Detection of an existing disease among individuals with symptoms
diagnostic testing vs screening
one has symptoms or lab findings, one is identifying possible disease with no symptoms
Tertiary Prevention
to reduce impact of disease among diseased individuals
Latent
Post Infection Pre contagious
incubation
post infection until clinical signs
clinical period
once symptoms appear
Endemic
Normal frequency of disease
sporadic
occasional disease that is unexpected but does not prompt further cases
epidemic
occurrence of disease in excess of normal expectancy
Pandemic
An epidemic on a world wide scale
Outbreak
occurrence of more cases of disease in a specific area, group of people over a period of time
Epidemiologic Triad
Host: “who” has the pathogen
Environment: “where” allowed for transmission
Agent: “what” microbe
Case defintion
a standard set of criteria for deciding whether an individual should have a health conditon
Attack rate
people who became ill / # people at risk
Attack rate ratio
attack rate among exposed / attack rate among unexposed
Screening
Testing to sort out asymptomatic people who may have a disease
Lead time
Interval by which the time of diagnosis is advanced by screening and early detection
Sensitivity
Ability for a test to correctly identify those who have disease
Specificity
ability of a test to identify who does not have the disease
PPV
What is likely hood they actually have disease if they test pos
NPV
What is the likely hood that they do not have the disease if they test neg
PPV and specificity/sensivity
higher sensitivity = higher PPV
SDOH
Conditions in the environment that affect an individuals health
impact of SDOH
major contributor to health disparities and inequities, progress towards health equity
Passive surveillance
simple, inexpensive
Active surveillance
health agencies seek reports, get complete reporting (STATES JOB)
Sentinel Surveillance
report of events by health professionals to represent a certain area or group, case control study, quantifies # cases
Syndromic Surveillance
reporting of events based on specific symptoms that may show large potential outbreak
