2025 | Verified and Graded A+
Epidemiology - study of the distribution (frequency, pattern) and determinants (causes,
risk factors) of health related states and events (not just diseases) in specified populations.
Roles of epidemiology in public health: - - monitor health of a pop
-respond to emerging public health problems
-promote research and use of evidence based interventions
-evaluate the effectiveness of interventions
-findings provide foundations for public health policy
-set funding priorities for research intervention programs
which components of epidemiology describes who gets the disease, where people with the
disease are located and how these aspects of disease change over time? - distribution
population - a group of people with a common characteristic in terms of person, place,
and time
crude mortality - number of deaths from all causes
age specific mortality - number of deaths from all causes in a specific age group
cause specific mortality - number of deaths from a specific cause
infant mortality - number of deaths of infants less than 1 year of age
prevalence rate - number of existing cases of disease
incidence rate - number of new cases of disease
disability - umbrella term for impairments, activity limitations, and participation
restrictions
disease frequency - quantification of the disease in the population: how often does the
disease occur
disease distribution - analysis of disease patterns: who, where, does it change over time
,epidemic - an increase in the number of cases of disease in a community, above what is
expected
endemic - a situation in a community in which there is a consistent elevated rate of a
certain disease
pandemic - an epidemic that is widespread across a country, continent, or a large
populace, possibly world wide (ex. aids)
ratio - division of one number by another, numbers dont have to be related
proportion - numerator is subset of denominator, often expressed as a percentage
rate - time is an intrinsic part of denominator, term is most misused
prevalence - number of existing cases of disease/ number in total population (at a point
or during a period of time)
incidence - number of new cases of disease that develop in the population at risk during
a specific time period
cumulative incidence - -number of new cases of disease/number in candidate population
(people who are at risk of getting disease) over a specified period of time
- estimates the probability or risk that a person will develop disease during a specified time
- used mainly for fixed populations
incidence rate - number of new cases of disease in the candidate population/ person
time of observation
relationship between incidence and prevalence - -incidence decreases but people are
living longer with the disease= increased prevalence
- the incidence increases but the duration is short= decreased prevalence
- the incidence decreases and the duration is short= decreased prevalence
relative risk - [a/(a+b)]/[c/(c+d)]
or rate in exposed/rate in unexposed
Relative Risk (RR)=1.0 - no association between exposure and disease
RR=2.0 - two times the risk of disease in the exposed compared to the unexposed
, RR=1.6 - 1.6 times the risk of disease in the exposed compared to the unexposed or 60%
increased risk of disease in the exposed (1.6-1.0=.60=60%)
RR-.5 - .5 times or 1/2 the risk of disease in exposed compared to the unexposed
odds ratio - -represents the odds that an outcome will occur given a particular exposure,
compared to the odds of the outcome occurring in the absence of that exposure
- most commonly used in case-control studies; can also be used in cross sectional and cohort
studies
OR equation - (a/b)/(c/d)
which condition must be met in order for the Odds ratio to approximate the relative risk? -
the disease must be rare
ecological study (correlational) - -unit of analysis: population or groups
- exposure status: based on the population
- time can vary
ecological fallacy - making assumptions about the individual based on findings at the
level of the population
cross sectional - -time: snapshot in time
-population- individual level (selected without regard to exposure or disease status)
-measure: prevalence of disease
- measure of association: OR
-cannot determine cause and effect
case control - -disease is rate
-disease has a long induction and latent period
-little is known about the disease
- selection of the cases
-selection of controls