EPI Test 2

What is the rank of study designs of the highest causality?

1) RCT, 2) Cohort, 3) Case Control, 4) Cross Sectional, 5) Case Series

A study was designed to assess the impact of sun exposure on skin damage in beach volleyball players. Players on SEC teams always use a popular brand of waterproof SPF 30 sunscreen whereas Big10 schools never use sunscreen. At the end of a weekend tournament, players skin from both teams was analyzed for skin damage and burns. What type of study design was used in this study? A. Cohort B. Case-control C. Cross-sectional D. Randomized controlled clinical trial

A

If the incidence of a disease among the exposed group is 10 per 100,000 and the incidence of disease among the unexposed is 2.5 per 100,000, what is the relative risk? A. 4.0 B. 5.0 C. 1.0 D. 2.0

A

In a 2x2 table, which exposure-outcome group is displayed in the top right corner? A. Subjects with the exposure but not the outcome B. Subjects with the exposure and the outcome C. Subjects with the outcome but not the exposure D. Subjects with neither the exposure nor the outcome

A

Researchers wanted to study the effects of exposure to pesticides in the workplace and the development of various outcomes. The researchers chose a group of farmers who routinely used pesticides and a group of farmers who did not use pesticides and followed them for 10 years for the development of various outcomes. This is an example of ___________ sampling. A- Exposure based B- population based

A

The essential difference between an experimental and an observational study is that in an experimental study, the: A- Investigator determines who is and who is not exposed to the risk factor. B- Study is prospective in direction C- Participants are selected based on their history of risk factor exposure D- Study is retrospective

A

The World Health Organization recently released a report stating that eating processed meat increases risk for colon cancer. The New York Times published an article summarizing and discussing the implications of this report. This New York Times article is an example of: A- popular literature B- Trade C- Grey D- Scholarly

A - popular literature

The null value for an odds ratios is ____ and the null value for a relative risk is ____. A. 0,1 B. 1, 1 C. 1, 0 D. 0,0

B

Blinding is: A. A type of bias that is present in prospective studies when the investigators don't collect enough data about the exposure B. A change of treatment for a patient in a clinical trial involving a switch of study treatments C. An aspect of study design wherein the subject is not aware of his/her group assignment of placebo or treatment D. A way of differentiating between prophylactic and therapeutic treatments, where the patient may not yet exhibit the symptoms that a treatment is intended to address

C

In the Belmont Report, respect for persons refers to: A- Treating individuals equally. B- Maximizing benefits and minimizing harm C-Individuals with diminished autonomy are treated the same as all other research subjects D- Allowing individuals to chose whether to participate.

C

The intention-to-treat principle states that: A. Participants are excluded from the analysis if they do not take their assigned treatment. B. Treatments are only assigned to participants who plan to follow the specified treatment regimen. C. Participants who do not take the assigned treatment are analyzed as though they did take the assigned treatment. D. None of the above

C

Which of the following circumstances would warrant the use of a cohort study design? A. The incidence of the disease is high in the nonexposed group B. The study population is the same with regard to the risk factors for disease C. The incidence of the disease is high in the exposed group D. The disease under study occurs rarely in the population

C

Which of the following is an advantage to the conduct of a cohort study? A. The study population includes a high number of undiagnosed, asymptomatic individuals with the disease B. The disease under study occurs rarely in the population C. The exposure under study occurs rarely in the population D. The incidence of the disease is high in the nonexposed group E. The incidence of the disease is high in the exposed group

C

Which of the following is not a part of the informed consent process for participating as a subject in a randomized controlled trial? A. Informing the subject about the potential pros and cons (risks and benefits) of participating in the trial B. Providing the subject a description of study procedures, identifying any that are experimental. C.Informing the subject that the lead investigator will determine the subject's assignment arm based on the subject's past medical history D. Providing the subject with a statement concerning the purpose of the study

C

What are three limitations of a case control study?

Can not deduce temporal relationship. unknown representativeness between cases and controls. can only study one outcome at a time.

Which of the following is not a research design employed in descriptive epidemiology? A: Case Report B: Case Control C: Cross Sectional D: Case series

Case Control

Why use case control over cohort?

Case-control studies are better for diseases with a low frequency.

Why use cohort over case control?

Cohort studies are best for diseases when the frequency/incidence is high.

In an RCT, investigators ensure that intervention and control groups are equivalent at baseline through: A. Selecting a random sample B. Manipulation C. Double-blinding D. Random assignment

D

Randomized controlled trials contain which of the following components: A. Rigorous inclusion and exclusion criteria B. Blinding or masking to prevent bias C. Comparable measurement of outcomes in treatment and control conditions D. All of the above

D

Researchers were interested in the effects of using olive oil on a daily basis on the risk of a second heart attack in men who had already had one heart attack. Men who used olive oil on a daily basis were compared to men who used butter in their diet. The men were followed over 5 years to determine whether the participants had a second heart attack. The RR estimate comparing regular olive oil users to men who usually used butter was 0.80. Which of the following is the best interpretation in words of this RR estimate? A. The risk of a second heart attack was lower in men who used olive oil compared to men who used butter. B. The risk of a second heart attack was 1.8 times higher in men who used olive oil compared to men who used butter. C.The risk using olive oil was 20% lower in men who had a second heart attack compared to men who had only one heart attack. D. The risk of a second heart attack in men who had a previous heart attack was 20% reduced in men who used olive oil compared to men who used butter.

D

Which of the following is NOT a disadvantage of case-control studies? A. Unable to deduce temporal relationships B. Can only study one outcome at a time C. Cases may inaccurately recall their exposure (recall bias) D. Cost prohibitive to collect data

D

All of the following are potential benefits of a randomized controlled trial, EXCEPT: A. The likelihood that the study groups will be comparable is increased B. Assignment of the next subject cannot be predicted C. Self-selection for a particular treatment is eliminated D. The therapy that a subject receives is not influenced by either conscious or subconscious bias of the investigator. E. External Validity of the study is increased.

E

What is the directionality of a cohort study?

Exposure measured first. Outcome measured second.

True or False: Temporal sequence can not be deduced from a cohort study.

False

True or False? Internal validity refers to the degree to which the results of a study may be generalized to a population.

False

True or False? The main objective when selecting controls for a case-control study is to exclude any controls that have any chance of becoming a case in the future.

False

True or false? The researchers cited in a peer-reviewed article have published papers consistent with the authors' conclusions.

False

The Centers for Disease Control has produced a report on disparities in breast cancer rates. This is an example of which of the following: A: Scholarly Literature B: Grey Literature C: News Articles D: Popular Literature

Grey Literture

Which of the following is a principle in the Belmont Report? A- Integrity B- Justice C- Virtue D- Trust

Justice

What is the directionality of a case control study?

Measure outcome first and exposure second

Is a case control design observational or descriptive?

Observational

What are the three types of cohort studies?

Retrospective, Prospective, and Historical Prospective

The New England Journal of Medicine published a case-control study of 200 women with colon cancer from the Iowa Women's Health Study. This journal article is an example of: A: Trade Literature B: Grey Literature C: Scholarly Literature D: Popular Literature

Scholarly Literature

The "peer" in peer review refers to reviewers who are experts in the same area as the author.

True

True or False. All subjects of a cohort study must be at risk of developing the disease.

True

True or False: All subjects of a cohort study must be disease free.

True

True or False: Cohort studies provide incidence data.

True

True or False? Cohort studies are ideal for studying rare exposures and common diseases.

True

True or False? Cohort studies preserve the temporality of cause (exposure) happening before the effect (disease).

True

Which of the following is NOT one of the three principles of the Belmont Report? Truth Beneficence Justice Respect for Persons

Truth

Which factor(s) distinguish study designs from one another? Data collection Unit of Observation Timing of data collection All of the above

all of the above

The purpose of a double-blind study is to: A. Achieve comparability of cases and controls B. Avoid Bias C. Reduce the number of subjects lost to a follow-up D. all of the above

b

what is population based sampling in cohort studies?

exposure is not known until the first observation when exposure information is collected

What exposure is "lack of directionality" in case controls not true for?

genetic markers

What is attributable risk?

incidence due to exposure

What is exposure-based sampling in cohort studies?

made up of subjects with a common exposure

Is the outcome in a cohort study measured retrospectively or prospectively?

prospectively

What measure of association is often used in cohort studies?

relative risk

Is the exposure assessment in case controls retrospective or prospective?

retrospective

Which of the following is NOT true of a cohort study? A. A cohort study requires randomization into exposed and unexposed groups before follow-up starts. B. A cohort study is usually very expensive to conduct. C. A cohort study usually requires a long follow-up period to ascertain development of a chronic disease. D. A cohort study is prospective or longitudinal.

A

With regard to study designs, temporality refers to: A. Ensuring that the exposure of interest occurs prior to the outcome of interest B. Ensuring that intervention and control groups are the same with respect to their medical histories C. Ensuring that the treatment lasts long enough to have a measureable effect on the outcome D. Ensuring that subjects give informed consent before they receive experimental treatments

A

Researchers at the Arnold School of Public Health performed a cohort study examining the association of cleaning agents used in locker rooms and the development of MRSA infection in football players. After analyzing the data, the researchers calculated a relative risk estimate of 2.0, when comparing cleaning agent X to cleaning agent Z. Which of the following statements is the best interpretation of the relative risk estimate? A.The risk of having used cleaning agent X is 2.0 times higher in locker rooms where MRSA infection was found compared to locker rooms where MRSA was not found. B. The risk of MRSA is 2.0 times higher in locker rooms cleaned using agent Z compared to locker rooms cleaned with agent X. C.The risk of using cleaning agent X is 2.0 times higher in locker rooms where football players get MRSA compared to locker rooms where cleaning agent Z is used. D.The risk of MRSA is 2.0 times higher in locker rooms cleaned with cleaning agent X compared to locker rooms cleaned with cleaning agent Z.

D

Researchers were interested in the association of alcohol use with esophageal cancer. Researchers recruited 175 patients from the local hospital who had a discharge diagnosis of esophageal cancer and 350 patients from the same hospital who had a discharge diagnosis unrelated to cancer (i.e., orthopedic patients, etc.). The subjects were asked to recall their alcohol use since adolescence via structured in-person interview. The exposure was divided into heavy alcohol use and little or no alcohol use. The calculated OR was 7.9. What is the best interpretation of this OR in words? A.The odds of esophageal cancer are 7.9 times higher in patients who are heavy alcohol users compared to those who do not have esophageal cancer. B.The odds of esophageal cancer are 7.9 times higher in patients who are heavy alcohol users compared to those who consume little or no alcohol. C.The odds of heavy alcohol use is 7.9 times higher in patients with esophageal cancer compared to patients who have little or no alcohol use. D.The odds of heavy alcohol use is 7.9 times higher in patients with esophageal cancer compared to patients without esophageal cancer.

D

True or False? Case-control studies are ideal for studying for studying very rare exposures.

False

True or False? Cohort studies are ideal for studying common exposures and very rare diseases.

False

True or False? In a cohort study, all potential study subjects must be initially free of the disease under investigation.

True

True or False? The most common type of bias in a cohort study is incomplete follow-up of participants.

True

Examples of descriptive epidemiologic studies do not usually include: A: Counts B: Cross-Sectional C: Cohorts D: Case series

cohorts