Epidemiological Studies Flashcards
List four applications of epidemiological studies.
Clarify clinical and demographic characteristics
Identify which populations are at risk
Provide clues to cause of disease
Guide in preventative measures and interventions
From the observations gathered during the descriptive process, a _____________ is generated about the causes of observed patterns, and the factors that increase the risk for disease or injury.
Hypothesis
Outline descriptive studies.
Describes the specific characteristics in a population of interest
What, when, where, who (from clinical Information and surveillance data)
Use accessible data
What (symptoms, lab results, etc.)
Who (demographics, e.g., age, race, gender, culture, etc.)
Where (where did illness begin, exposure occur, etc.)
When (time, trends, patterns, epidemics, etc.)
List three forms of descriptive study.
Case report
Case series
Incidence study
What two values do descriptive studies principally measure?
Prevalence and incidence
What is the aim of analytical epidemiology?
Attempts to provide the ‘why’ and ‘how’ of such health-related events, by comparing groups of individuals
Name three epidemiological determinants.
Agents
Hosts
Environments
__________ epidemiology attempts to determine the cause of an outbreak.
Analytical
Experimental analytical epidemiology is also called _____________ epidemiology.
Interventional
Describe experimental epidemiology.
Investigator can control the exposure
Akin to laboratory experiments, except living populations are the subjects
Generally, involves random assignment to groups, following over time and monitoring
Clinical trials are the most well-known experimental design (generating data from individuals)
This type is the ultimate step in testing causal hypotheses
In an experiment, there is an interest in the consequences of some treatment on some outcome
The subjects in the study who receive the treatment of interest are called the treatment group
The subjects in the study who receive no treatment, or a different treatment, are called the comparison group or control group
What is a randomised control trial?
A design with subjects randomly assigned to treatment and comparison groups
List three advantages of randomised control trials.
First randomization reduces the influence of other determinants of exposure and outcomes, i.e., confounding
The ‘gold standard’ of research designs
Provides most convincing evidence of relationship between exposure and effect
State four disadvantages of randomised control trials.
Randomized control trials can be costly
People who participate in RCTs may be very different from the rest of the population.
Randomized control trials usually focus on a specific, narrow research question related to a certain treatment or medication and a specific comparison with another treatment or exposure
Ethical considerations must be made when randomizing treatments or exposures
True or false: it is not possible to use RCTS to test effects of exposures that are expected to be harmful, for ethical reasons.
True
What occurs in an observational study?
Researcher does not determine who is exposed, but rather observes the outcomes (no intervention)
What is an observational study?
Documentation of a naturally occurring relationship between exposure and outcome, e.g., incidence of lung cancer in smokers versus non-smokers
Name the four main types of observational study.
Cross-sectional
Cohort
Case-control
Ecological
Describe cohort studies.
Determine exposure
Observe if illness occurs
Often called incidence studies
Involves groups of individuals who share similar characteristics (same school, same occupation, etc.)
In cohort studies, participants are divided into two groups: ‘exposed’ and ‘unexposed’
Individuals undergo observation, to determine ‘disease’ or ‘no disease’
State two features of a cross-sectional study.
Surveys both exposure and disease of individuals at a particular time
Demonstrates the relationship between disease and exposure, or non-exposure
____________ studies can be retrospective or prospective.
Cohort
True or false: a case-control study is usually conducted before a cohort or an experimental study to identify the possible aetiology of the disease.
True
A _____________ study is preferred when the disease is rare because investigators can intentionally search for the cases.
Case-control
Describe case-control studies.
Identify ill cases and comparison group
Compare exposures
Used to retrospectively determine if there is an association between an exposure and a specific health outcome.
Proceed from effect (e.g., health outcome, condition, disease) to cause (exposure)
Collect data on exposure retrospectively
Are observational studies because no intervention is attempted, and no attempt is made to alter the course of the disease
A ____________ study involves comparing individuals with a particular condition or disease (cases), to a group of individuals with the same general characteristics, but without the condition or disease (controls).
Case-control
