ch 6 Flashcards
1
Q
what is the goal of epi research?
A
conduct an epi study to determine the relationship between an exposure of interest and disease/outcome of interest with validity and precision using the minimum amount of resources
2
Q
what are the 6 components of a study?
A
- population
- outcome
- exposure
- potential confounders
- analysis
- communicate findings
3
Q
what is the difference between the source population and the study population?
A
- source: pop that you are interested in knowing more about
- study: pop that you enroll in your study to represent the source population
4
Q
case definition? goal?
A
- description of the event you are interested in studying by combining info on the signs, symptoms, physical examinations, and results
- the goal is to minimize errors
5
Q
confounders? purpose?
A
- can. lead to distortion of true association between exposure and disease
- identify and control confounder
6
Q
analysis two types?
A
- crude estimate (if no CF)
- adjusted estimate(if CF) - standardization, stratified analysis, multivariate analysis
7
Q
who do you communicate findings to? examples
A
- appropriate persons or community that you have found even if there is no association
-peer-reviewed articles, conferences, and government reports
8
Q
what are the two types of analytical studies?
A
- experimental - clinical trials, experimental study
- observational - cohort study, case-control study
9
Q
what is an experimental study?
A
investigates actively manipulates which group receives the agent under the study
10
Q
what is the purpose of the experimental study? key features?
A
- study prevention and treatment for the disease
- assigns two plus groups that receive or do not receive the therapeutic agent and follow the group for incidence of outcome
11
Q
what is the setting of the experimental study?
A
- ethical/feasible
- small effect
- money available
- noncompliance issue
12
Q
what is the purpose of the cohort study? key features?
A
- studies cause prevention and treatment for the disease
- investigator selects subjects according to their exposure level and follows them for disease occurrence
13
Q
what is the setting of the cohort study?
A
- trial is not feasible, ethical, or too expensive
- little is known about the exposure so an evaluate the effects of exposure
- exposure is rare
14
Q
what are the three types of cohorts?
A
- prospective cohort study
- retrospective cohort study
- ambidirectional cohort study
15
Q
what is the purpose of a case-control study? key features
A
- studies causes, preventions, and treatments for diseases
- methods of sampling a population where subjects are identified as having the disease (cases) or are from the source population that give rise to the cases (controls) and exposure distribution is compared
16
Q
what are the settings of a case-control study?
A
- trial not ethical, feasible or too expensive
- moderate or large effect expected
- little known about the disease so evaluate many exposures
- the disease is rare
17
Q
what is an observational study? Does the research question involve? types
A
- investigator watches
- research question involves prevention, treatment or causal factors
- cohort, case control study
18
Q
limitations and effect size of an observational study
A
- the trial is not ethical/ feasible and too expensive
- investigator does not have complete control
- moderate to large effect expected
19
Q
What does a source population need? what effect does having a small difference?
A
- must include enough number of individuals to determine if there is a true difference between treatment and comparison group
- The smaller the difference the larger the sample size must be
20
Q
what is needed from an individual to participate in a study? how are they assigned?
A
- consent - mus give oral and written consent + understand objectives and risks/benefits of participating
- randomization = less bias
21
Q
what do placebos do? three types?
A
- masks the treatment to prevent bias - ensures accuracy
- single - participant does not know
- double mask- participant and clinical (unconscious bias) do not know
- triple mask - indiv + clinical + people analyzing the data do not know
22
Q
what should we consider when we are choosing a type of design?
A
- research question
- existing scientific knowledge
- frequent exposure and disease
- ethical consideration
- concerns about validity/ random effects/ efficiency
23
Q
Typically examines multiple health effects of an exposure;
subjects are defined according to their exposure levels and
then followed for disease occurrence
A
Cohort
24
Q
Studies causes, preventions, and treatments for diseases;
investigator passively observes as nature takes its course
A
observational
25
Typically examines multiple exposures in relation to a
disease; subjects are defined as based on their disease
status, and exposure histories are compared
case-control
26
typically examines the relationship between exposure and
disease prevalence in a defined population at a single point
in time
cross-sectional
27
Examines the relationship between exposure and disease
with population-level data
ecological
28
Studies preventions and/or treatments for diseases by
actively manipulating group assignments
experimental
29
When planning to conduct an epidemiological study,
it is acceptable to consider the cost of the study when deciding on which study design to use. (T/F)
T
30
Which of the following is NOT a key feature of a cross-sectional study design?
a. A limitation may include selection of case-participants with long durations of disease.
b. Generally speaking, this type of study design can be cheaper than other studies to conduct.
c. This study design uses population-level factors, which may be inferred to individuals.
d. This study cannot infer a temporal sequence between exposure and disease if the exposure
is a changeable characteristic.
c
31
Cohort studies often include prevalent cases to increase the sample size of the study design (T?F)
f
32
Informed consent may be obtained by oral or written consent?
T
33
Which of the following study designs would researchers likely use randomization techniques to help
reduce the influence of confounding variables?
a. Case-control study designs
b. Cohort study designs
c. Cross-sectional study designs
d. Community trials to test new preventive messaging strategies compared to standard
messaging strategies
D
34
he measure of association used in case-control study designs is known as:
a. The prevalence rate
b. The odds ratio
c. The risk ratio
d. The rate ratio
B
35
Which of the following study designs might use matching as a strategy for obtaining comparison
groups?
a. Ecologic studies
b. Cross-sectional surveys
c. Case-control studies
d. Retrospective cohort studies
e. Prospective cohort studie
C
36
Which of the following best describes the stance of Equipoise?
a. A state of mind characterized by legitimate uncertainty or indecision as to choice or
course of action.
b. Study participants consciously or unconsciously change their behavior just because they are
being studied.
c. A type of selection bias that results from comparing an unexposed group of workers to the
general population; occurs because death and disease rates among a working population
are usually lower than those of the general population.
d. A judgment in which the investigator relates the conclusions of a study beyond the study
setting and population to a broader setting and population.
A
37
Which of the following study designs begins by selecting people with the disease of interest (cases)
and people without the disease of interest (controls) and comparing their exposure histories?
a. Cross-sectional survey
b. Retrospective cohort study
c. Case-control study
d. Experimental study
c
38
A study that evaluates the relationship between breast cancer and a woman’s history of breast feeding. The investigator selects women with breast cancer and an age‐matched sample of women who live in the same neighborhoods as the women with breast cancer. Study subjects are interviewed to determine if they
breastfed any of their children.
case-control
39
A study that evaluates two treatments for breast cancer. Women
with stage 1 breast cancer are randomized to receive either
lumpectomy alone or lumpectomy with breast radiation. Women
are followed for five years to determine if there are any
differences in breast cancer recurrence and survival.
clinical
40
A study of the relationship between exposure to chest irradiation
and subsequent risk of breast cancer that was begun in 2010. In
this study, women who received radiation therapy for post‐
partum mastitis in the 1940s were compared to women who
received a non‐radiation therapy for post‐partum mastitis in the
1940s. The women were followed until 2009 to determine the
incidence rates of breast cancer in each group.
retrospective study
41
A study of the relationship between exposure to postmenopausal
hormone therapy and subsequent risk of breast cancer that will
begin in January 2016. In this study, postmenopausal women who
receive hormone therapy during 2016 will be compared to
postmenopausal women who not receive this therapy. The women
will be followed until 2026 to determine the incidence rates of
breast cancer in each group.
prospective cohort study
