George Washington University

PRACTICE PROBLEMS FOR MIDTERM EXAM PubH 6003, Fall 2018

1)_C_ death occurs in 10 percent of cases of meningococcal meningitis

1. _D_ approximately 9 people die each year in the United States for every 1,000 persons estimated to be alive

2. _E_ lung cancer deaths in men ages 60-69 expressed as a proportion of all men 60-69

3. _A_ the number of deaths due to cardiovascular disease expressed as a proportion of all causes of death

4. When a new treatment is developed that prevents death but does not produce recovery from a disease, the following will occur:

1. 1. Prevalence of disease will decrease
   2. Incidence of disease will increase
   3. Prevalence of disease will increase
   4. Incidence of disease will decrease
   5. Incidence and prevalence of disease will decrease

5. Age-adjusted death rates are used to:

1. 1. Correct death rates for errors in the reporting of age
   2. Determine the actual number of deaths that have occurred in specified age groups in a population
   3. Correct death rates for missing age information
   4. Compare deaths in persons of the same age group
   5. Eliminate the effects of differences in the age distributions of populations in comparing death rates

6. The incidence rate of a disease is three times greater in women than in men, but the prevalence rates show no sex differences. The best explanation is that:

1. 1. The crude all-cause mortality rate is greater in women
   2. The case-fatality rate for this disease is greater for women
   3. The case-fatality rates for this disease is lower in women
   4. The duration of this disease is shorter in men
   5. Risk factors for developing the disease are more common in women

7. In a cross-sectional study of peptic ulcer in a community, people meeting the symptomatic criteria for peptic ulcer were found in 80 per 100,000 men aged 35 to 49 and 90 per 100,000 women aged 35 to 49. The inference that in this age group, women are at greater risk of developing peptic ulcer is:

1. 1. Correct
   2. Incorrect due to failure to distinguish between incidence and prevalence
   3. Incorrect because rates were used to compare males and females
   4. Incorrect due to failure to recognize a possible cohort effect
   5. Incorrect because there is no comparison or control group

8. A case-control study is characterized by all of the following except:

1.                                 It is relatively inexpensive compared with cohort studies and randomized controlled trials
2. Cases with the disease are compared to controls without the disease
3. Incidence rates may be directly calculated from case control studies
4. Assessment of past exposure may not be accurate
5. Controls are assumed to come from the same population as the cases

9. Women in an urban community who were planning to become pregnant were recruited into a study about home insecticide use and pregnancy outcomes. The women were asked questions about their use of home insecticides and were also given personal monitors to wear to collect exposure data. The women were followed for two years and data about pregnancy outcomes were collected.  What type of study is this?

1. Prospective cohort
2. Case-control
3. Retrospective cohort
4. Case cohort

10. Women who had a caesarean delivery and women who had a vaginal delivery were recruited from a hospital obstetrics ward to participate in a study looking at the association between type of delivery and exercise during pregnancy. After delivery, women were provided with a questionnaire to ask about their nutrition and exercise habits while pregnant. What type of study is this?

1. Prospective cohort
2. Case-control
3. Retrospective cohort

11. A study was conducted to determine the association between occupational benzene exposure and leukemia. Workers from 200 benzene factories and 80 control factories in China were recruited for the study in 2015. The workers had all been employed at the plant between 1985 and 2014. The researchers then linked the historical factory employment records with mortality records to determine mortality from leukemia among the study population. Which of the following is true about this study?

1. It is a prospective cohort study

                                           b. It is a retrospective cohort study

c.It is a case control study

12. An interview study was carried out to evaluate risk factors for migraine headaches. Interviewers went door-to-door and surveyed a random sample of individuals in a rural community. Participants were asked if they had ever been diagnosed with migraine. They were also identified by age, gender, and race, and asked about a number of exposures, including dietary patterns, psychological factors, sleep patterns, medication use, alcohol consumption, and exposures to electromagnetic fields (EMF). What measure of association would you use to describe the relationship between migraines and EMF?

1. 1. Relative risk
   2. Incidence rate
   3. Prevalence
   4. Prevalence odds ratio

Identify the measure of disease.-on an exam you would be given a list to choose from

13. A 2006 mumps outbreak resulted in 1,643 confirmed cases in Iowa.

14. Data from several studies that used the current criteria for diagnosing autism spectrum disorders (ASD) estimate that as many as 1 in 166 children may have ASD.

15. The World Health Organization recently reported that hemorrhage was the leading cause of pregnancy-related mortality in Africa, accounting for 33.9% of maternal deaths.

16. In an outbreak of Extensive Drug Resistant tuberculosis (XDR-TB) in South Africa, 52 of 53 patients with XDR-TB died.

17. A recent study published in the Journal of the American Medical Association found that approximately 1 in 4 American women (age 14 to 59 years) are infected with HPV.

18. Approximately 45 out of every 100,000 people in the early 1970s developed mononucleosis each year.

19. At a graduate student picnic, 28 students ate egg salad sandwiches and 26 became ill with salmonella enteritidis (food poisoning) that evening.

20. In 1849, nearly 3 out of every 100 people in Chicago died from cholera.

21. In the late 1990s, 6.6 of every 1,000 people in Azerbaijan died each year.

22. To monitor trends in cancer incidence and mortality, the Washington State Department of Health mandates that all cancer diagnoses and cancer deaths are reported to the Washington State Cancer Registry. Investigators compiled the following data for mortality due to stomach cancer in 2000 in Washington State. Using the data presented below, calculate the following rates:

1. Cancer mortality rate (for males):

2. Cancer mortality rate (total population):

3. Stomach cancer mortality rate (for females):

4. Stomach cancer mortality rate (total population):

5. Proportionate mortality for stomach cancer deaths (total population):

6. Crude mortality rate (total population):

7. Cancer incidence (total population):

8. Stomach cancer incidence (total population):

1. Case fatality rate of stomach cancer in the total population. (Note: assume all stomach cancer deaths were also new stomach cancer diagnoses in 2000.)

23. Multiple Sclerosis (MS) is an autoimmune disease that affects the central nervous system (brain, spinal cord, and optic nerves). Myelin is fatty substance that surrounds the nerves of the central nervous system and helps the nerves conduct electrical impulses. In a person with MS, their body attacks the myelin, destroying and damaging it. Because of this damage, the ability of the nerves to conduct electrical impulses from the brain is compromised and people with MS experience a variety of symptoms including fatigue, difficulty in walking, and spasticity. For reasons that are currently unknown but may be related to exposure to sunlight and Vitamin D and genetics, white people, especially those of Northern European descent, are at higher risk of this disease than other racial groups. Suppose we are interested in examining the incidence of MS in two different cities, San Diego and Seattle.

The following data are available regarding the incidence of MS in San Diego and Seattle:

1. What is the crude incidence rate of MS in Seattle and San Diego?

2. Compare the crude incidence rate to the adjusted incidence rate. The incidence rate adjusted for race is 1.47/1000 for San Diego and 1.48 /1000 for Seattle. What do you conclude about the incidence of MS in Seattle and San Diego?

24. Suppose the surveillance system for MS in Minneapolis has not collected racial data on people with MS. From the census, we know the racial composition of Minneapolis.

1. What is the crude incidence rate of MS in Minneapolis?

2. If Seattle is the standard population, which city has proportionately more people at high risk of MS (i.e., white)?

3. If the expected number of MS cases in Minneapolis is 651 based on using Seattle as the standard population, what is the SMSR (standardized MS ratio, equivalent to SMR)?

4. How does the incidence of MS in Minneapolis compare to Seattle?

25. Which of the following is a benefit of a randomized clinical trial?

3. 1. The likelihood that the study groups will be comparable is increased
   2. Patients may self-select for a particular treatment
4. Assignment of the next subject can be predicted
5. The investigator can influence which therapy a patient receives.

26. In 2010, an investigator conducted a study about bone cancer from exposure to radium paint. Records dating back to 1940 were obtained for women who worked with the paint as well as women who worked in the administrative offices. Women were matched to mortality data from 1940 to 1990 to determine the risk of dying from bone cancer in the women who worked with paint compared to the women in the administrative offices. What type of study is this?

1. 1. Randomized controlled trial
   2. Case-control study
   3. Prospective cohort study
   4. Retrospective cohort study
   5. Cross sectional study

27. An investigator reviewed the medical records of 200 children seen for care at Children’s National Medical Center in the past year and identified 40 with asthma. He also identified 40 children who were free of asthma. The families of the children were interviewed regarding the children’s exposure to second hand smoke and other environmental factors. This study is an example of

1. 1. Case control
   2. Prospective cohort study
   3. Retrospective cohort study
   4. Ecological study

28. A study is designed to evaluate the impact of a daily multivitamin on students’ academic performance. 160 students were randomly assigned to receive either the multivitamin or the placebo and are instructed to take the assigned vitamin daily for 20 days. Performance on exams was then compared between the two groups at the end of the 20 day period. What type of study is this?

1. 1. Case control
   2. Randomized clinical trial
   3. Prospective cohort
   4. Retrospective cohort
   5. Cross sectional

29. A study is designed to evaluate the impact of a daily multivitamin on flu. A survey was conducted and 1000 adults were asked about their daily multivitamin use over the past year and whether or not they had been diagnosed with the flu over the past year. Prevalence of flu diagnosis was compared between vitamin and non-vitamin users. What type of study is this?

1. 1. Case control
   2. Randomized clinical trial
   3. Prospective cohort
   4. Retrospective cohort
   5. Cross sectional

30. A clinical trial is conducted to evaluate a new pain medication for arthritis. Patients are randomly assigned to receive new drug or standard treatment. 110 patients received the new medication and an equal number received the standard treatment. Of the patients who received the new medication 44 reported pain relief while 21 reported pain relief in the standard treatment group. What is the appropriate measure of association to report?

A.            RR=2.1 (44/110)/(21/110)

B.            OR=2.83

C.            RR=1.60

D.            We don’t have enough information to calculate a measure of association.

For extra practice identifying study designs only. These are not representative of exam questions! Identify the outcome, exposure, and study design for each abstract.

32. Lancet. 1995 Aug 26;346(8974):530-6.

Impact of improved treatment of sexually transmitted diseases on HIV infection in rural Tanzania:

33. N Engl J Med. 2006 Jun 22;354(25):2645-54.

Condom use and the risk of genital human papillomavirus infection in young women.

34. Lancet. 1993 Mar 6;341(8845):581-5.

35. JAMA. 2004 May 12;291(18):2204-11.

36. JAMA. 1987 Feb 13;257(6):790-5.

Postservice mortality among Vietnam veterans. The CDC Vietnam Experience Study.

37. J Nutr. 2007 Jun;137(6):1460-5.

Gender and marital status clarify associations between food insecurity and body weight.

38. Am J Epidemiol. 1981 Dec;114(6):873-9.

Risk factors for staphylococcal toxic-shock syndrome.

39. Int J Epidemiol. 2006 Apr;35(2):386-96. Epub 2005 Nov 3.

Childhood leukaemia in Belarus, Russia, and Ukraine following the Chernobyl power station accident

40. Radiat Environ Biophys. 2006 Sep;45(3):159-66. Epub 2006 Aug 4.

Mortality from cardiovascular diseases in the German uranium miners cohort study, 1946-1998.