Intro Lecture Flashcards
(25 cards)
Define endemic
constant presence of disease or infectious agent within a given geographic area or population group
may also refer to usual prevalence of a disease within an area or group
ex- tuberculosis is endemic to the US
Define Epidemic
occurrence in a community or region of cases with frequency clearly in excess of normal expectancy
time is a consideration
could mean just 1 case of disease or 100s
Example- FMD
Define Pandemic
epidemic occurring over a very wide area, crossing international boundaries and affecting a large number of people- may cross continents
Ex- HIV, SPnaish Flu, Plague
Define Epidemiology
study of disease in populations
study of distribution and determinants of heath-realted states or events in specified populations and the application of this study to control health problems
scientific inquiry
data driven
systematic and unbiased approach
collection, analysis, interpretation
What are examples of health related states and events
states- preggers, obesity, diabetes, lameness
events- parturition, visit to the dog park
abnormal blood sugar test, stepping on a nail
What is a CASE DEFINITION
set of standard criteria
clinical description
laboratory criteria
case classification
National Stnadards that ensure comparability
ie listeria cases in orego women in 200 compared to 2015, iowa compared to Minnisota
surveillance and putbreak definitions often differ
What are the three parts to an epidemiologic approach?
count- cases/events by person/place/thing
divide- by the appropriate denominator to calculate rates
compare rates over time for groups
What are the 2 types of epi studies?
Descriptive/analytic
What is a descriptive study?
who, where, and when- person place time
characterizing patterns
hypothesis generating
What is an analytic epi study?
determinants
identifying causes
hypothesis testing
What are the strengths/limitations of descriptive studies?
strengths- inexpensive, quick, overall descriptive pattern, generate hypothesis
weakness- cannot control for confounding factors, difficult to est cause and effect, cannot test hypotheses
What are the 5 W’s of dscriptive epi?
What- case definition who- person/animal where- place when- time why/how- causes, risk factors, modes of transmission
What are the properties we look at for person/animal?
inherent characteristics- age, sex, species, ethnicity/race/breed
biological characteristics- immune status
acquired characteristics- marital status
activities- occupation, leisure, use of meds/drugs
socioeconomic status
What are the properties we look at for place?
where is the disease?, most common? most rare?
does it vary by region? tropical/temperature?
What are the properties we look at for time?
seasonal? inlfuenze, WNV, salmonellosis
day of week/time of day?
difference after intervention?
What are the 2 types of descriptive studies?
case reports and case series
cross sectional analysis
What is a cross-sectional studies?
exposure and disease assessed simultaneously
one point in time
specific population
What are the strengths/limitations of cross sectional studies?
strength- fast, based on general population, lots of data
weak- difficult to separate cause and effect, temporal relationship cant be defined, dz with remissions could be missclassified
What is the major difference between descriptive.analytic epidemiology?
descriptive- distribution of disease
analytical- determinants of disease
What are the key features of analytical epidemiology?
KEY- comparison group
experimental studies- clinical trial
observational studies- cohort/case-control
What is a cohort study?
based on EXPOSURE status
persons are enrolled as dz free, w/ or w/o exposure of interest
followed over time
What are the strengths/limitations of of cohort studies?
strengths- risk ratio, info on incidence, temporal relationship, rare exposures
weakness- time concuming, large sample size, expensive, lots of follow-up/bias, not efficient for rare data
What is a case-control study?
based on DISEASE status
persons w/ disease (cases) and w/o disease (controls)
faster/cheaper
can investigate multiple exposures for one dz- useful for when dz is rare
not good for when dz exposure is rare
odds ratio
Advantages to case-control matching?
confounding variables-
better than adjustment, littermates/genetic/environmental influence, avoids wasting power on known factors
ie non-hospitalized control group
