Medicine Expert Q&A

Consider the following 2 × 2 table from a hypothetical cohort study.Calculate the relative risk of CVD comparing those with high fasting glucose (≥126 mg/dL) with those with normal fasting glucose (<126 mg/dL) $$\begin{array}{lccc}\text{ Serum fasting glucose }& \text{ Developed CVD }& \text{ Did not develop CVD }& \text{ Total }\\ \ge 126\mathrm{mg}/\mathrm{dL}\text{ (exposed) }& 125& 325& 450\\ <126\mathrm{mg}/\mathrm{dL}\text{ (not exposed) }& 50& 500& 550\\ \text{ Total }& 175& 825& 1000\end{array}$$

A) 0.33
B) 0.75
C) 1.02
D) 3.08
E) 5.34

An outbreak of measles occurred in City A.There were 1,000 confirmed cases among children younger than 10 years old.Unfortunately,50 children died of measles.Fifty represent 5% of the total number of cases.What concept is being illustrated in this example?

A) Attack rate
B) Secondary attack rate
C) Case-fatality rate
D) Incubation period
E) Subclinical disease

In a cohort study of smoking and myocardial infarction in City A,the number of myocardial infarctions were 250 cases among 7,000 smokers and the number of myocardial infarctions were 150 cases among 20,000 nonsmokers.From another source,a cross-sectional study,we know that 30% of the total population in City A were smokers.What is the population proportion attributable risk of smoking in City A?

A) 15%
B) 30%
C) 53%
D) 79%
E) 90%

Epidemiologists decided to investigate the effect of sunscreens on sunburns.They ran an epidemiologic study to see the association of sunscreens and sunburns.Overall,460 people have enrolled in the study.Investigators randomly allocated 230 people to the treatment group (sunscreens) and 230 to the control group (placebo) .They exposed those 460 people to the high mountain trail on a sunny day.At the end of the study,30 people developed sunburns in the sunscreen group and 130 people developed sunburns in the placebo group.What type of study design is this?

A) Cross-sectional study
B) Prospective cohort study
C) Case-control study
D) Randomized trial
E) Case-control study.

Which of the following biases is the most accurate explanation of the following situation? Epidemiologists are studying the possible relationship of cholera infections to drinking water.They conduct a case-control study and interview patients with cholera infection (cases) and persons without cholera infection (controls) .A patient who was diagnosed with cholera often tries to identify all kinds of information related to drinking water.However,controls who were not diagnosed with cholera may not remember water they drink which is not from an unhygienic source.

A) Recall bias
B) Selection bias
C) Misclassification bias
D) Publication bias
E) Exclusion bias

A researcher finds that the standardized mortality rate (SMR) for epidemiologists compared with the general population is 100.What does that mean?

A) The observed number of deaths for epidemiologists is the same as the expected.
B) Epidemiologists have a mortality rate 100 times greater than the general population.
C) Epidemiologists have a mortality rate 100 times lower than the general population.
D) The general population experience a mortality rate increased as compared with epidemiologists.
E) Nothing can be said with this information.

What is the primary purpose of randomization?

A) To prevent bias in the assignment of treatment
B) To provide a probability basis for statistical testing
C) To ensure the same number of people are randomized to each group
D) To ensure that the subjects not to know which group they are assigned to
E) To guarantee the comparability of the different treatment groups

A physical examination,digital rectal exam,was used to screen for prostate cancer in 290 men with biopsy-proven prostate cancer and in 516 age- and race-matched control men,all of whom showed no evidence of cancer at biopsy.The results of the physical examination were positive in 136 cases and in 165 control men.What is the specificity of the physical examination?

A) 32%
B) 47%
C) 53%
D) 68%
E) Cannot calculate it based on given information

What is the incidence rate from influenza in the 2016 season in the young age group at Minas Tirith? Use the following table to answer the question. Number of Residents,Diagnosed Cases,and Deaths From Influenza by Age
$$\begin{array}{llll}\text{ Age group }& \begin{array}{l}\text{ No. of residents }\\ \text{ during }2016\text{ season }\end{array}& \begin{array}{l}\text{ No. of diagnosed }\\ \text{ cases from influenza }\\ \text{ during }2016\text{ season }\end{array}& \begin{array}{l}\text{ No. of deaths from }\\ \text{ influenza during }2016\\ \text{ season }\end{array}\\ \text{ Young }& 20,000& 3,000& 300\\ \text{ Old }& 10,000& 1,000& 500\end{array}$$

A) 3,000 cases
B) 150 cases/1,000 people
C) 1,000 cases
D) 100 cases/1,000 people
E) 15 cases/1,000 people

Participants in a clinical trial might report different symptoms when they know they are part of the intervention group instead of the control group.To avoid that,researchers use the following:

A) Confounding
B) Randomization
C) Concealment of random allocation
D) Masking
E) Effect modifiers

According to the Centers of Disease Control and Prevention (CDC) ,during the Ebola outbreak of 2014 in West Africa,there were a total of 14,124 Ebola cases in Sierra Leone and 3,956 deaths due to Ebola.What was the case fatality rate in that country?

A) 3.5%
B) 22%
C) 28%
D) 3,956
E) 14,124

Smoking participants of a cohort study are more likely to drop out.It is known that the effect of asbestos on getting cancer is much stronger among smokers.When analyzing data for this study,researchers find no association between asbestos and cancer.A potential explanation for the results of the study is

A) confounding.
B) effect modification.
C) selection bias.
D) information bias.
E) specificity of association.

In 2016 there were 7,467 million people in the world.According to the World Health Organization,in the same year there were 56.9 million deaths worldwide; of those,15.2 million were due to ischemic heart disease or stroke.What was the proportionate mortality of those two causes combined for that year?

A) 0.8%
B) 0.2%
C) 3.7%
D) 13.5%
E) 26.7 %

A researcher study of Baltimore's neighborhoods showed that those neighborhoods with lower median household income experienced a higher teen pregnancy rate.What type of study design was used?

A) Cohort
B) Case-control
C) Ecologic
D) Experimental
E) Randomized trial

At an initial examination in Baltimore,Maryland,disease X was found in 10 of 1,000 men aged 40 to 50 years and in 10 of 2,000 women aged 30 to 40 years.Which of the following statement is the most accurate inference for the risk of developing disease X?

A) Men have a 2 times greater risk of developing disease X than women.
B) Women have a 2 times greater risk of developing disease X than men.
C) People aged between 40 and 50 years have a 2 times greater burden of developing disease X than people aged between 30 and 40.
D) People aged between 30 and 40 years have a 2 times greater burden of developing disease X than people aged between 40 and 50.
E) We cannot make any inference of risk of developing disease X.

In a clinical trial,researchers might influence the selection of participants into a group (intervention or control) ,hence introducing bias into the study.What can be done to prevent from this threat to the validity of the study?

A) Confounding
B) Randomization
C) Concealment of random allocation
D) Masking
E) Effect modifiers

In the student's health clinic of a certain university,140 cases of foot-hand-mouth disease were identified among the undergraduate students.This viral infection is usually mild,and none of the students got any complication.Because it is rare to observe this condition in people older than 10 years,the university reported their findings to the city's health department.Three officers were sent to the university to interview and examine all the infected students and their contacts.By sending the three officers,what type of surveillance was implemented by the city health department in response to the university's report?

A) Sentinel
B) Periodic
C) Systematic
D) Passive
E) Active

A researcher study of Baltimore neighborhoods showed that those with lower median household income experience a higher teen pregnancy rate.After reading this,someone concludes that a teenager with low income is more likely to get pregnant.What is the name of this mistaken conclusion?

A) Selection bias
B) Information bias
C) Confounding
D) Ecologic fallacy
E) Group misinterpretation

Which of the following information is not significant for a urologist to make a diagnosis of a urologic disease?

A) Changes in frequency or urgency of urination
B) Difficulty or pain with urination (dysuria)
C) How far the patient can walk
D) Incontinence
E) Unusual discharge from the urethra

The population of Oriol City in June 2018 was 612,437.According to the Oriol City's health department,there were 329 new cases of Raven's disease during 2018.Counting those new cases,by December 31 it was estimated that there were 6580 persons with Raven's disease in Oriol City.What was the prevalence of Raven's disease in 2018?

A) 26 per 100,000 population
B) 33 per 100,000 population
C) 54 per 100,000 population
D) 1074 per 100,000 population
E) 5000 per 100,000 population