1Epidemiology Flashcards
Epidemiology
Study of distribution (who has the disease, where/when) and determinants (the factors, exposures, characteristics, behaviors that determine the patterns) of health disease in human populations
Historic focus vs current focus of epidemiology
Historic:
-acute illnesses
-epidemics
Current:
-chronic diseases
-pandemic
Epidemic
UNEXPECTEDLY large number of cases in a particular population
Endemic
Disease that occurs REGULARLY in a population as a matter of course
(Louisville: flu, covid, RSV, alzehimers, heart disease)
Pandemic
Out break over WIDE GEOGRAPHIC area
Why we study epidemiology
Make meaningful comparison of disease frequency between:
-diseases (cause of death)
-population subgroups (men/women)
-places (urban/rural)
-time period (before/after intervention)
Types of epidemiology
Descriptive
Analytical
5 factors of epidemiology
Describe the occurance of a disease
Distribution
Frequency
Population
Determinants
Descriptive epidemiology
Person:
-physical, sociodemographic, behavior
Place:
-geographic patterns, spatial patterns(john snow)
Time:
-frequency, general patterns
Analytic epidemiology
Examines relationship among determinants of diseases
With the triangle: HOST—AGENT—ENVIRONMET
Analytical epidemiology
What affects the host
Age and gender
Genetic susceptibility
Immunological status
Lifestyle factors (diet, exercise)
Analytical epidemiology (agent)
Factors that cause a health problem
Infectious agents (bacteria, fungi, viruses, parasites)
Chemical agent (pesticides, toxic chemicals)
Physical agents (radiation)
Analytical epidemiology (environmental factors)
Climate: temp, rainfall
Working condition
Socioeconomic status (also affect host)
Human population distribution (crowdes, urban heat island(take all trees cause it to be hot)
Communicable vs non-communicable
Communicable (infectious):
Flu, malaria, covid
non-communicable (non infectious):
HTN, HD, COPD
Chain of infection
Step by step model of source to host
Agent (Cold)—
reservoir (throat)—
portal of exit (mouth/nose)—
Transmission (saliva droplets)—
Portal of entry. (Mouth)—
New infection
Direct transmission
Transmitted through touching, kissing, sexual intercourse:
STIs
Mono
Impetigo
Lice
Scabies
Indirect transmission
Types
Has intermediate step. Not direct
Airborne
Vehicle borne (inanimate object)
Vector borne (animal or insect)
Airborne infections
Measles
Chickenpox
TB
Influenza
Vector-borne
West nile virus
Lyme disease
Malaria
Foodborne infections
Norovirus
Salmonellosis
Hep A
E. Coli
Clostridium botulinum
Universal precautions
Assuming everyone is sick
(Precautions we take with everyone)
Surveillance
Collection, analysis, and interpretation of data related to occurence of disease and health status in a given populatiom
Surveillance
Active vs passive
Report cases to who
Active: purposefully seeking out new cases of disease
Passive: commonly used by local/state health dept.
Has to be repoted otherwise CDC via NETS
Data we use in epidemiology
Vital records (birth-death certificates)
Surveillance
Insurance records
Original data (john snow going door to door)
Mortality vs morbidity
Mortality: death
Morbidity: rate of disease
Risk
Probability that an event will occur within a specified time period
Usually a %
Rate
How often a health event in a defined population in a specified period of time
Attack rate
Proportion of persons who are exposed to an agent and develop the disease
Is a %
Incidence rate
Prevalence rate
I:
Occurance of NEW cases of a disease over time
P:
Covers total cases
Numerator vs denominator for calculating incidence rate
Numerator is new cases
Denominator is total population
Mortality statistics is what
Most reliable measure of population health status
Crude mortality rate
Vs
Age-adjusted rates
Crude:
Number of deaths/ population TOTAL
Age:
Makes comparisons of relative risk across groups and over time when groups differ in age
Again numerator vs denominator for RATE
N: # of occurances
—————————
D: total population
Prevalence rate calulation
Does it test for acute or chronic things?
of existing cases in population at a specific time
————————————————————————
Total population
Test chronic thing while incidence rates test acute things
Prevalence measures new and existing cases at a given time
True or false?
True
Experimental study
Treatment and exposure occur in a controlled setting
Randomized Control Trail:
One group gets it other doesnt
Cross sectional study
Examines or surveys exposures and outcomes at one point in time
Prospective
Looks forward in time
Examines future events
Follows a disease or condition or group of people over time
Retrospective
Looks back in time
Examines events that have already occurred
Elimination vs eradication of disease
Elim:
Stopping a disease in a defined geographical region
Eradication:
Total elimination from the world population
Levels of prevention
Primary, secondary and tertiary
Primary vs secondary vs tertiary
Primary : PREVENT (they dont have anything yet)
-exercise, diet, vaccinations, education
Secondary: SCREEN (do or dont have it yet)
-PAP smear, mamogram, BP
Tertiary: TREATMENT (do have it)
-ABX, rehabilitation, education on how to use inhaler
Immunity (Natural vs artificial)
Natural acquired:
Active: exposure to antigen ( previously infected causes resistance to getting it again)
Passive: contains antibodies (antibodies through placenta)
Artificial acquired:
Active: vaccine of live or tamed virus/portion of virus
Passive: antibody injection
