epidemiology Flashcards
research
scientific method by which data is systemically collected to describe, explain, predict events
evidence based practice
conscientious and judicious use of current best evidence to guide healthcare decisions
draw conclusions
epidemiology
research method most commonly used in PH (guide), foundation of evidence based practice
study of distribution, freq, determinants of health + disease in human pop to understand cause
epidemiology - objectives
who is affected by d/o -> pop, measured and defined, any health related state
what determine who is affected/what makes susceptible -> SDOH, rf
where does condition occur -> distribution
when does it occur -> freq
why does condition occur -> disease causation, answering previous questions will often provide this answer
how can we control and prevent health problems -> application
where and when = person, place, time, natural hx
epidemiology: major subdivisions
infectious disease, genetics, molecular, injury, occupation, chronic disease, cancer, env, social, behavior
methods commonly used - focus
identify factors and characteristics that cause, predict, or are associated with the development of a health conditions
methods commonly used - scientific methods
1: surveillance (track disease), ongoing, systematic collection, analysis, interpretation of health related data essential
2: descriptive epidemiology, describe who, what, where, when
3: analytic, examine relationships btw who, what, where, when to determine why
models
epidemiological triangle and web of causation
used to describe factors (who, what where, when, why, how) and explain associations among them
epidemiological triangle (triad)
bidirectional arrows, impact can go both ways -> dynamic
agent, host, env, vector (sometimes)
model works well with communicable or infectious, NOT chronic and menal bc focus is too narrow
epidemiological triangle (triad) - agent
factor that causes disease
consider:
type -> chm, infectious (bacteria), phys (heat/cold, machine, radiation)
ability to conjure or cause illness (how deadly, infectivity, pathogenicity, virulence, toxigenicity)
epidemiological triangle (triad) - vector
pass pathogen to host
mosquito
epidemiological triangle (triad) - host
living species capable of being infected or affected
consider:
exposure
response -> can impact whether or not they get the disease
susceptibility
epidemiological triangle (triad) - env
all external, influenced and influences host and/or agent
allow agent to divide and multiply, where they may interact
consider:
phys, bio, psych factors (not really used) -> find interactions and break them to prevent spread
host factors
intrinsic
susceptibility/response to agent
factors: gene, age, sex, phys state, hx immunological (active/passive), concurrent or preexisting disease (asthma), human behavior (social distance, masking)
env factors
extrinsic
influence existence of agent, exposure, susceptibility
phys
bio: human pop, flora, fauna
socioeconomic: occupation (essential workers), urbanization, economic dev, disruption, violence
epidemiological triangle (triad) - 2 assumptions
disease occurs when agent present in susceptible host under env conditions favorable to dev of disease
change = goal of PH
change in 1 component of triangle can influence whether or not disease occurs
web of causation
more complex
investigate relationships btw factors r/t who, what, where, whem, why
used to study chronic disease bc multiple interacting concepts (factors, causes)
somethings inside and outside control
break links by identifying them
data sources: routinely collected
collected on regular basis
vital statistics (marriage, divorce, death, birth), US census, national center for health statistics
data sources: epidemiologic data
data collected specifically for epidemiologic purpose to examine health issues
scientific studies, pop screen, surveillance
data sources: data collected for other reasons
info gathered from providers, hospitals, health department, insurance, etc, EMR
rate
freq with which event occurs in defined pop during specific time period
way to measure occurrence
usually used to determine likelihood of event
divide occurrence (numerator) by total pop of interest over same time period (denominator)
K: constant, ex = “per 1,000”, built in number we can use to make sense of
can compare rates btw causes
rate = (occurence / total pop) x K
fertility rate
of people who can become pregnant age 15 - 44 during the same year
of live births during 1 year
—————————- x 1000
crude mortality
of deaths from all causes during 1 yr
not adjusted by age, non cause specific
—————————————- x 1000
estimated pop during same year
cause specific mortality rate
of deaths from specific cause during time period
——————————— x 1000
estimated pop during same time period
ex: infant mortality rate
# of deaths of infants < 1 yr old during 1 year
——————————— x 1000
total # of live births during the same year
morbidity rates
not interchangeable
incidence = new
prevalence = current
incidence
of new cases of specific health condition
——————————– x 1000
estimated pop at risk during same time period
prevalence
of current cases of a specified health condition
———————————– x 1000
estimated population at risk during the same time period
risk
% or proportion, higher = greater likelihood of occuring
# of all experiencing
—————————— x 1000
# of all at r/o experiencing
odds
from 0 - infiniti or proportion, 6:1 = 6 will experience for every 1 person that does not
# of all experiencing
—————————— x 1000
# of those who dont experience
YPLL
years of life potential
age adjusted measure of premature mortality
how many people could have lived and contributed (usually to economy) to nations wellbeing died earlier than expected
compare btw countries
US = < 75
increased death in young = increased YPLL
reliability
extenet a measuring procedure yields conssitent results on repeated admin of a scale
exact same results every time
validity
degree a measuring procedure accurately reflected or assesses or captures the specific concept that the researcher is attempting to measure
measure what you actually want to measure
sensitivity
ability of test to correctly identify those with disease, true +
specificity
ability of test to correctly identify those without disease, true “-“
