NR503 Population Health, Epidemiology, & Statistical Principles
Week 4 Midterm Exam
Endemic means that a disease:
A. Occurs clearly in excess of normal expectancy
B. Is habitually present in human populations
C. Affects a large number of countries simultaneously
D. Exhibits a seasonal pattern
E. Is prevalent among animals
Table who ate egg salad & who did not eat egg salad
Total number of persons who ate each specified combination of food items
Ate tuna Did not eat tuna
Ate egg salad 75 100
Did not eat egg salad 200 50
Total number of persons who ate each specified combination of food items & who later became sick (with acute sore throats)
Ate tuna Did not eat tuna
Ate egg salad 60 75
Did not eat egg salad 70 15
What is the sore throat attack rate in persons who ate both egg salad & tuna
e. None of the above
According to the results shown in the preceding tables, which of the following food items (or combination of food items) is most likely to be infective?
a. Tuna only
b. Egg salad only
c. Neither tuna nor egg salad
d. Both tuna & egg salad
e. Cannot be calculated from the data
In the study of an outbreak of an infectious disease, plotting an epidemic curve is useful because:
a. It helps to determine what type of an outbreak (e.g. single-source, person-to-person) has occurred
b. It shows whether herd immunity has occurred
c. It helps to determine the median incubation period
d. A & c
e. A,b, & c
Which of the following is characteristic of a single-exposure, common-vehicle outbreak?
a. Frequent secondary cases
b. Increasing severity with increasing age
d. Cases include both people who have been exposed & those who were not exposed
e. All of the above
At an initial examination in Oxford, Mass migraine headaches was found in 5 of 1,000 men aged 30 to 35 years & in 10 of 1,000 women aged 30 to 35 years. The inference that women have a two times greater risk of developing headaches than do men in this group is:
A prevalence survey conducted from January 1 through December 31, 2012 identified 1,000 cases of schizophrenia in a city of 2,000,000 persons. The incidence rate of schizophrenia in this population is 5/100,000 persons each year. What percent of the 1,000 cases were diagnosed in 2012?
Which of the following is an advantage of active surveillance?
What would be the effect on age specific incidence rate of uterine cancer if women with hysterectomies were excluded from the denominator of the calculations, assuming that there are some women in each age group who have had hysterectomies?
A survey was conducted among the non-hospitalized adult populations of the united states during 2008 through 20122. The results from this survey are shown below.
Age group Persons with HTN %
70 & older 64
The researchers stated that there was an age related increase in the risk of hypertension in this population. You conclude that the researchers interpretation:
Next two questions relate to the information below:
Population of the city of Atlantis on March 30, 2012 = 183,000
No of new active cases of TB occurring between January 1 & June 30, 2012 = 26
No of active TB cases according to the city register on June 30, 2012 =264
The incidence rate of active cases for the 6 month period was:
The prevalence rate of active TB for the month of June was:
The following two questions are based on information provided below:
In an Asian country with a popularion of 6 million people, 60,000 deaths occurred during the year ending December 31, 2010. These included 30,000 deaths from cholera in 100,000 people who were sick with cholera.
What was the cause specific mortality rate from cholera in 2010?
What was the case fatality from cholera in 2010?
Age adjusted death rates are used to:
The mortslity rate from disease X in city A is 75/100,000 in persons 65 to 69 years old. The mortality rate from the same disease in city b is 150/100,000 in persons 65 to 69 years old. The inference that disease X is two times more prevalent in persons 65 to 69 years old in city B than it is in persons 65 to 69 years old in city a is:
The incidence rate of a disease is five imes greater in women thn in men, but the prevalences rates show no sex difference. The best explantiaon is that:
For a disease such as pancreatic cancer, which is highly fatal & of short duration:
Annual Cancer Deaths in white Male workers in two industries
Industry A Industry B
Cancer site # of deaths % of all cancer deaths # of deaths % of all cancer deaths
Respiratory system 180 33 248 45
Digestive system 160 29 160 29
Genitourinary 80 15 82 15
All other sites 130 23 60 11
Totals 550 100 550 100
Based on the preceding information, it was concluded that workers in industry B are at higher risk of death from respiratoy system cancer than workers in industry A. (Assume that the age distributions of the workers in the two industries are nearly identical.)
Which of the following statements is true?
A program manager from an international health funding agency needs to identify regions that would benefit from an intervention aimed at reducing premature disability. The program manager asks a health care consultant to develop a proposal using an index that would help her make this decision. Which of the following would best serve this purpose?
The following are st&ardized mortality ratios (SMRs) for lung cancer in Engl&:
St&ardized mortality ratios
Occupation 1949-1960 1968-1979
Carpenters 209 135
Bricklayers 142 118
Based on the SMRs alone, it is possible to conclude that:
The rate of death from lung cancer in carpenters in 1968-1979 was greater than would have been expected for a group of men of similar ages in all occupations.
A screening tests is used in the same way in two similar populations, but the proportion of false positive results among those who test positive in population A is lower than that among those who test positive in population B. What is the likely explanation for this finding?
A physical examination & an audiometric test were given to 500 persons with suspected hearing problems, of whom 300 were actually found to have them. The results of the examination were as follows
Result Present Absent
Positive 240 40
Negative 60 160
Result Present Absent
Positive 270 60
Negative 30 140
Compares with the physical examination , the audiometric test is:
Two pediatricians want to investigate a new laboratory test that identifies strep infections. Dr. Kidd uses the st&ard culture test, which has a sensitivity of 90% & a specificity of 96%, Dr. Childs uses the new test which is 96% sensitive & 96% specific. If 200 patients undergo culture with both tests which of the following is correct?
Which of the following is a good index of the severity of a short term acute disease?
A diagnostic test has been introduced that will detect a certain disease 1 year earlier than it is usually detected. Which of the following is most likely to happen to the disease within the 10 years after the test is introduced? (Assume that early detection has no effect on the natural history of the disease. Also assume that no changes in death certification practices occur during the 10 years.
Which of the following statements about relative survival rate is true?
Before reporting the results of this survival analysis, the investigation compared the baseline characteristics of the 42 persons who withdrew from the study before its end with those of the participants who had complete follow up. This was done for which of the following reasons:
The major purpose of r&om assignment in a clinical trial is to:
An advertisement in a medical journal stated that “2,000 subjects with sore throats were treated with our new medicine, within 4 days 94% were asymptomatic” The advertisement claims that the medicine was effective. Based on the evidence given above the claim:
The purpose of a double blind or double masked study is to:
In many studies examining in the association between estrogens & endometrial cancer of the uterus, a one sided significance test was used. The underlying assumption justifying a one-sided rather than a two-sided test is:
In a r&omized trial, a planned crossover design:
A r&omized trial comparing the efficacy of two drugs showed a difference between the two (with a P value <0.05). Assume that in reality, however, the two drugs do not differ. This is therefore an example of:
All of the following are potential benefits of a r&omized control trial, except:
In cohort studies of the role of a suspected factor in the etiology of a disease, it is essential that:
Which of the following is not an advantage of a prospective cohort study
Retrospective cohort studies are characterized by all of the following except
A major problem resulting from the lack of r&omization in a cohort study is:
In a cohort study, the advantage of starting by selecting a defined population for study before any of its member become exposed, rather than starting by selecting exposed & non-exposed individuals is that:
A case control study is characterized by all of the following except:
a) It is relatively inexpensive compared with most other epidemiologic studies
b) Patients with the disease (cases) are compared with persons without the disease (controls)
c) Incidence rates may be computed differently
d) Assessment of past exposure may be biased
e) Definition of cases may be difficult
Residents of three villages with three different types of water supply were asked to participate in a survey to identify cholera carriers. Because several cholera deaths had occurred recently, virtually everyone present at the time underwent examination. The proportion of resident in each village who were carriers was computed & compared. What is the proper classification for this study?
Which of the following is a case control study?
In a study begin in 1965, a group of 3,000 adults in Baltimore were asked about alcohol consumption. The occurrence of cases of cancer between 1981 & 1995 was studied in this group. This is an example of:
In a small pilot study, 12 women with endometrial cancer & 12 women with no apparent disease were contacted & asked whether they had ever used estrogen. Each woman with cancer was matched by age, race, weight, & parity to a woman without the disease. What kind of study design is this?
The physical examination records of the entire incoming freshman class of 1935 at the University of Minnesota were examined in 1977 to see if their recorded height & weight at the time of admission to the university was related to the development of coronary artery disease by 1968. This is an example of:
In a case control study, which of the following is true?
a) The proportion of cases with the exposure is compared with the proportion of controls with exposure
b) Disease rates are compared for people with the factor of interest & for people without the factor of interest
c) The investigator may choose to have multiple comparison groups
d) Recall bias is a potential problem
In which one of the following types of study designs does a subject serve his own control?
Ecologic fallacy refers to:
In a study of disease in which all cases that developed were ascertained, if the relative risk for the association between a factor & the disease is equal to or less than 1.0, then:
Rates of ASHD per 10,000 population, by age & sex, Framingham massachusetts
Age at beginning of study ASHF rates at initial exam Yearly follow up exams ASHD rates at initial exam Yearly follow up exams
29-34 76.7 19.4 0.0 0.0
35-44 90.7 40.0 17.2 2.1
45-54 167.6 106.5 111.1 29.4
55-62 505.4 209.1 211.1 117.8
The relative risk for developing ASHD subsequent to entering this study in men as compared to women is :
The most likely explanation for the difference in rates of ASHD between the initial examination & the yearly follow u exam in men is:
Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking. This measure is an example of:
In a large case control study of patients with pancreatic cancer, 17% of the patients were found to be diabetic at the time of diagnosis compared to 4% of a well matched control group that was examined for diabetes at the same time as the cases were diagnosed. It was concluded that the diabetes played a causal role in the pancreatic cancer. This conclusion is:
An investigator examined cases of fetal death in 27,000 pregnancies & classified mothers according to whether they had experienced intercourse within 1 month before delivery. It was found that 11% of the mothers fetuses that died & 2.5% of the mothers of the fetuses that survived has had sexual intercourse during the period. It was concluded that intercourse during the moth preceding the delivery caused the fetal deaths. This conclusion:
All of the following are important criteria when making causal inferences except:
a) Consistency with existing knowledge
b) Dose-response relationship
c) Consistency of association in several studies
d) Strength of association
e) Predictive values
Factor X is :
Factor A is: