Epidemiology Flashcards
Study of the distribution of health related conditions in specified populations and the determinants of these health events
ETYMOLOGY
Components of Epidemiology
- Study
- Frequency
- Distribution: how many of… who? Where? When?
- Determinants: how? Why?
- Health-Related data V.S. Disease
- Populations/Communities
- Application
Applied science, practice, health prevention,
health promotion
Application
How does one element influence the occurrence
of the events
Determinants: how? Why?
answers the question “how many?” (number of
times the health event occurs)
○ Frequency
Father of Western Medicine
Hippocrates
Father of Modern Epidemiology
★ Figured out the cause of Cholera breakout in the
past was because of the Broad street pump
handle being used by infected people therefore
spreading the disease (First beginnings of
Epidemiology
John Snow
T or F
Today, we use to have this register of infant baptism, so it’s usually the churches or the parishes that have these records of the neighborhood, the community data. in front baptisms would then correlate with the births in the community. and they would also have a census of the people who died
because the people used to bury their dead usually at
the back of the church.
false
in the earlier times we used to have this register of
infant baptism, so it’s usually the churches or the
parishes that have these records of the neighborhood,
the community data. in front baptisms would then
correlate with the births in the community. and they
would also have a census of the people who died
because the people used to bury their dead usually at
the back of the church.
pertains to the number of people who are disease
free at the start of data collection. so they can
develop the disease throughout the time that the
data is being collected. But the requirement is
that at the start they do not have the condition.
Population-at-risk
★ It is the prerequisite for measuring the frequency
Case definition
It means the person bearing the outcome of
interest. If the outcome of interest is the absence
of disease, they can be a case. But, if you want the
outcome of interest to them having a condition,
then there is also a case
CAse
★ Describes HOW COMMON an illness (or other
health event) is related to the size of the
population (population-at-risk) and a measure
of time
Measures of disease frequency
Purposes of Epidemiological studies
Causation of disease
○ Describing the natural history of disease
★ Includes the disease outcomes (who survives? Who dies?)
○ Describing the health status of the population
○ Evaluating interventions
○ For public health intelligence and public health promotion efforts
A type of study where measurements like disease rates and information about exposures are made on a group of people
ECOLOGICAL
STUDIES
Describes the
characteristics of a group of people
who have the same disease or the
same exposure
CASE SERIES
The aim of the study is to understand the demographics, clinical presentations, prognosis or other characteristics of people who have a particular disease
● It may also describe something unusual
○ early 1980s had an occurrence of an unusual
pneumonia in men which led to the identification of
HIV
CASE SERIES
A study that takes a selected population and measure health
information at a given point in time
○ gives a snapshot of their health
CROSS
SECTIONAL
It involves asking participants a series of questions using
questionnaires
CROSS
SECTIONAL
● These studies are also called this,
because they measure how many
people have a disease at a particular
point in time
● The selected population must be the
representative of the total population
PREVALENCE STUDIES
It uses a comparison group called controls who are similar to cases but do not have the disease
○ both groups are asked about their previous exposures to
different risk factors
CASE
CONTROL
STUDY
Each of the risk factors the odds of
being exposed if they were a case is
compared to the odds of being
exposed if they were a control this is
called an ODDS RATIO
caswe controol study
T or F
An odds ratio of MORE THAN ONE
means that people with the disease are
more likely to have been exposed to
that risk factor than people without
the disease
○ this suggests that it could be a
possible cause of the disease
● An odds ratio of LESS THAN ONE
suggests that it’s a PROTECTIVE
FACTOR
● It is the ratio between the risk of
disease in the exposed group
compared to the risk of disease in the
unexposed group
RELATIVE RISK (RR)
a well-known cohort study in the
1950s
● This study provided valuable
scientific evidence of the
HARMFUL EFFECTS OF SMOKING
especially the LINK BETWEEN
SMOKING AND LUNG CANCER
BRITISH DOCTOR STUDY
ADVANTAGES OF THE COHORT STUDY
time sequence of events can be determined this is useful when trying to determine what caused a disease
information about several different outcomes and risk
factors can be collected at the same time
○ this allows for some analysis to be conducted
on the data
DISADVANTAGES OF THE COHORT STUDY
The high cost and they can involve a large number of people
being followed over a long period of time
● They’re generally not suitable to study rare diseases
● Ensuring that people who started the study stay until the end of the study if many people drop out it
will affect the results of the study
T or F
In an cognitive study, an
intervention is done on a group of
people and the outcome studied
TRUE
In an interventional study, an
intervention is done on a group of
people and the outcome studied
It is the best study design for an
interventional study
● For example, we want to study the
effects of a new drug we start off
with a study population
RANDOMIZED CONTROLLED STUDY
A situation where the neither the
participants nor investigators know
which group had the intervention
DOUBLE BLINDING
ADVANTAGES OF THE RANDOMIZED CONTROL
STUDIES
t can provide good evidence that the
intervention led to an outcome
● Randomization ensures that both
groups have an equal chance of
receiving the intervention and that
they have similar characteristics this
way the effect of the intervention can
be determined without other factors
influencing the outcome
DISADVANTAGES OF THE RANDOMIZED
CONTROL STUDIES
Generally quite expensive to do
● it may also require a large number of
participants
● It is not always possible due to it
having the possibility of being
unethical
T or F
● Meta analysis review identifies all the
relevant studies on a given topic
FALSE
● Systematic review identifies all the
relevant studies on a given topic
This study assesses, synthesizes,
interprets the findings and finally
presents an impartial, unbiased, and
balanced summary of the evidence.
Systematic Review
T or F
Meta analysis is a study that uses
data from all the studies that
consider the same question and use
the same study design.
● It uses data from these studies to
combine statistical analysis and
produces a single summary result.
TRUE
Factors that are positively associated with the
risk of development of a disease but that are not
sufficient to cause the disease
rISK fACTORS
Levels of prevention
Primordial Prevention
primary Prevention
○ Secondary Prevention
○ Tertiary Prevention
consists of measures to reduce impairments and
disabilities, minimize suffering caused by poor
health and promote patient’ adjustment to
incurable conditions
○ Tertiary Prevention
to reduce the more serious consequences of
disease through early diagnosis and treatment;
directed at the period between disease onset and
normal time of diagnosis
★ It can only be applied to diseases in which the
natural history includes an early period, when it
is easily identified and treated, so that the
progression can be stopped
Secondary Prevention
to avoid the emergence and establishment of the
social, economic, and cultural patterns of living
known to contribute to an elevated risk of
disease.
Primordial Prevention
to limit the incidence of disease by controlling
specific causes and risk factors
■ Population approach
■ High-risk approach
Primary Prevention
The process of usings tests on a large scale to identify
the pressure of disease in apparently healthy people.
○ Screening tests do not usually establish a diagnosis,
but rather the presence or absences of an identified
risk factor, and thus require individual follow-up and
treatment.
Prevention: Screening
Types of screening:
○ Mass:
○ Multiple or multi-phasic:
○ Targeted:
○ Case-finding or opportunistic:
○ Mass
★ This aims to screen the whole population, or a subset of the population.
○ Multiple or multi-phasic
★ It’s just a use of several screening tests.
○ Targeted
★ This is the screening of groups with specific exposures like the workers in the lead battery factories.
○ Case-finding or opportunistic
★ consult a health practitioner for other purposes.
Prevention: Screening criteria
○ Disorder
○ Prevalence
○ Natural history
○ Test choice
○ Test performance
○ financial/costs
○ Acceptability
○ Equity
○ Reliability
t’s getting the same results for a repeated administration of your desk, meaning it’s reliable
Reliability
