Jefferson College of Population Health; PBH 506 Fundamentals of Epidemiology (Fall 2020)

Problem Set #2 (50 points): Please type your answers and highlight your response. Show your calculations whenever appropriate. Upload your document (must be compatible with Microsoft word) on Canvas AND to the Problem Set #2 Quiz portal. You may work with others on the Problem Set. You may work with others on the Problem Set. For each question on which you worked with someone else, please note your collaboration.

Use the following information to answer questions 1-2. There were 250 students enrolled at the Kip City Public School at the beginning of the 2015-2016 school-year.  At the beginning of the year, school nurse records indicated that 42 of the students had asthma.  During the school year (September 1 through June 30), 18 additional children were reported to have a diagnosis of asthma. No children were enrolled in the school or left the school during the school year.  You can assume that an asthma diagnosis is permanent, so once a child is diagnosed, they are never cured.

1.   (2 points) What was the baseline prevalence rate of asthma in this population at the beginning of the school year?

2.   (3 points) What was the incidence rate for asthma in this population during the school year?

Questions 3-6: An investigation of disease registries identified the following heart disease mortality data among two different (fictitious) cities in Pennsylvania (Quartz City and Zachary) in the year 2015:

Quartz City    
GroupAge (years)Total PopulationDeathsAge-specific Death Rate
10 to 41500370 
25 to 1460089 
315 to 1930070 
420-5990070 
560+15043 
Zachary    
GroupAge (years)Total PopulationDeathsAge-specific Death Rate
10 to 440070 
25 to 14600100 
315 to 19500100 
420-59750120 
560+650170 

3. (3 points; Please fill in table above) What are the age-specific mortality rates for Quartz City and Zachary (per 100 population)?

4. (2 points) What are the crude mortality rates, overall, for Quartz City and Zachary (per 100 population)?

5. (2 points) How do the rates compare between Quartz City and Zachary? Why might the use of crude mortality rates not be a good way to compare death rates between Quartz City and Zachary?

6. (3 points) Given what you know about the health influences of population-based characteristics of person, place, and time, provide 3 possible explanations for the differences (or similarities) of rates between Quartz City and Zachary.

Table 1 below describes the morbidity of disease X in two populations stratified by age:

 Population APopulation B
AgeNumber with Disease (n)Number in Population (N)Number with Disease (n)Number in Population (N)
< 181310,0004735,000
18-352615,0002320,000
36-652925,0002522,000
> 655430,0004718,000

7. (2 points) What are the crude morbidity rates, overall, for Population A and Population B (per 100000)?

8. (1 point) What is the crude morbidity rate among 18-65 year olds in Population B (per 100000 population)?

Table 2 is just like table above, but also provides information on a reference population stratified by age categories.

  Population APopulation B
AgeReference PopulationNumber with DiseaseNumber in PopulationExpected in Population ANumber with DiseaseNumber in PopulationExpected in Population B
< 1825,0001310,000 4735,000 
18-3525,0002615,000 2320,000 
36-6525,0002925,000 2522,000 
> 6525,0005430,000 4718,000 

9. (5 points) Using Table 1 and Table 2, find the age-adjusted morbidity rates for Population A and Population B using the direct age-standardization process. How do the adjusted rates compare between Population A and Population B? Please explain your answer.

Use the following information for question #10. The table below provides information about the rates of morbidity due to an emerging infectious disease (named DOSx) in a reference population stratified by age group, and also the number of residents in Population C stratified by age group. Also, you know that the total number of people who acquired DOSx in Population C was 89.

  Population C
Age GroupRate of Disease in Reference PopulationNumber with DiseaseNumber in PopulationExpected Disease # in Population  
< 1838/10,00010,078 
18-3513/10,00024,564 
36-6526/10,00022,998 
> 6535/10,00043,090 

10. (4 points) Calculate and interpret the Standardized Incidence Ratio (SIR) for DOSx in Population C.

11. (4 points) How and why do mortality and morbidity differ by sex? Explain and relate your discussion to the female paradox, and discuss both genetic and environmental factors. Please limit your answer to 2 paragraphs.

12. (4 points) If John Snow were to conduct his study of cholera deaths in present day time, where could he get cholera morbidity and mortality data? List two possible secondary data sources (one for mortality data and one for morbidity data) and be as specific as possible. Please limit your answer to 2 paragraphs.

  1. (4 points) You are interested in reducing obesity among teenage girls aged 12-17. Describe one primary prevention approach and one secondary prevention approach you would use. Make sure to convey your understanding of the difference between primary and secondary approaches, and be specific about defining your population. Please limit your answer to 2 paragraphs.

Multiple Choice (1 point each)

14. When analyzing public health data, an abrupt drop in mortality due to a specific disease from one year to the next is most likely due to:

            A.        incorrect listing of cause of death by the physician on the death certificate

B.        coding mistake by nosologists when using the International Classification of Disease (ICD) system

            C.        A and B

            D.        a change in the International Classification of Disease (ICD) system

            E.         fewer older persons dying from chronic diseases each year

15. Cyclic variations in the occurrence of disease may reflect:

            A.        Changes in exposure to infectious agents

            B.        Changes in the risk-taking behavior of persons

            C.        Changes in temporary stressors

            D.        Endogenous biologic factors

            E.         All of the above

16. Cautious use of information from death certificates is warranted because:

            A.        certificates are not available for everyone who dies in the U.S.

            B.        certificates are often erroneous for date of death and sex

            C.        cause of death information may not be correct

            D.        autopsy results are not included

            E.         all of the above

17. Large international variations in rates of infectious and communicable diseases as well as other conditions are likely explained by:

            A.        differences in climate

            B.        differences in cultural factors

            C.        national dietary habits

            D.        access to health care

            E.         all of the above

18. Which of the following data sources is most likely to provide a representative sample of the general health status of a population?

            A.        hospital outpatient statistics

            B.        absenteeism data

            C.        data from public health clinics

            D.        a cross-sectional morbidity survey of the general population

            E.         electronic medical records, supplemented with interviews

19. What is one of the widely used sources of statistical data on cancer?

A.        Disease registries

            B.        Vital statistics

            C.        Special survey apportionments

            D.        Hospital clinic statistics

20. High rates of mortality from hypertension found among African Americans may be due to:

            A.        Dietary factors

            B.        Exposure to stress

            C.        Lack of social support

            D.        Obesity

            E.         All of the above

21. The Vital Statistics Registration System in the U.S. collects data on all vital events including:

            A.        births

            B.        deaths

            C.        fetal deaths

            D.        A and B only

            E.         A, B, and C

22. Descriptive epidemiology characterizes the amount and distribution of disease within a population and enables the researcher to:

            A.        make direct tests of etiologic hypotheses

            B.        generate testable hypotheses regarding etiology

            C.        evaluate trends in health and disease within a population

            D.        all of the above

            E.         B and C only

23. A null hypothesis is most similar to which of the following?

            A.        Positive declaration

            B.        Negative declaration

            C.        Implicit question

            D.        Mill’s canon of neutrality

24. At Thomas Jefferson University, new employees need to get 5 screening tests as part of the new employee health examination to detect various diseases. What is the name for this type of screening program?

A.        Selective screening

B.        Mass screening

C.        Ad hoc screening

D.        Multiphasic screening