FPH 7240 – Introduction to Epidemiology

FPH 7240 – Introduction to Epidemiology

Fall 2019

Assignment 3

Due: Thursday, September 19, 2019 at noon

Readings: Aschengrau & Seague, Ch. 5 “Descriptive Epidemiology” & Ch. 6 “Overview of Epidemiologic Study Designs”

Question 1:

The following questions are based on the Research Article Summary of the paper, “Changing dynamics of the drug overdose epidemic in the United States from 1979 through 2016” by Jalal et al., published in Science in 2018. (Note: The full article is also included if you would like to see the more detailed findings, but the questions below can be answered from the one page summary on the first page).

a) From the one-page summary, what is your best assessment of what the case definition is in this study?

In questions b, c, and d, below, please summarize the descriptive epidemiology of the findings presented in this one-page summary with respect to the following:

b) Person (who is dying from drug overdoses?)

c) Place (where is risk of overdose death highest?)

d) Time (how did drug overdose patterns change over time?)

Question 2:

Use the data from a real, closed population in the tables below to answer the following questions:

Deaths and Death Rates from an Unusual Event, by Sex and Socioeconomic Status

		Socioeconomic Status
Sex	Measure	High	Middle	Low	Total
Males	Persons at risk	179	173	499	851
	Deaths	120	148	441	709
	Death rate (%)	67.0	85.5	88.4	83.3
Females	Persons at risk	143	107	212	462
	Deaths	9	13	132	154
	Death rate (%)	6.3	12.6	62.3	33.3

Deaths and Death Rates from an Unusual Event, by Age and Socioeconomic Status

		Socioeconomic Status
Sex	Measure	High/Middle	Low	Total
Adults	Persons at risk	566	664	1230
	Deaths	287	545	832
	Death rate (%)	50.7	82.1	67.6
Children	Persons at risk	36	47	83
	Deaths	3	28	31
	Death rate (%)	8.3	59.6	37.3

a) Describe the death rate patterns for the “Unusual Event” between men and women overall and by socioeconomic status.

b) What was the relative risk of death for men compared with women? Please describe your finding in a sentence.

c) What was the relative risk of death for high-SES vs. low-SES females? What was the relative risk of death for high-SES vs. low-SES males? Please describe your answers in a sentence or two.

d) Describe the death rate patterns for the “Unusual Event” among adults and children overall and in different socioeconomic classes.

e) Assuming low socioeconomic status is a cause of death in this unusual event, what proportion of deaths among the low-SES adults could have been prevented if they were instead in the high/middle SES group? Please describe this finding in a sentence.

f) Describe the death rate patterns for the “Unusual Event” among the different socioeconomic classes overall (men and women combined from the data provided in the first table).

		Socioeconomic Status
Sex	Measure	High	Middle	Low	Total
Males	Persons at risk	179	173	499	851
	Deaths	120	148	441	709
	Death rate (%)	67.0	85.5	88.4	83.3
Females	Persons at risk	143	107	212	462
	Deaths	9	13	132	154
	Death rate (%)	6.3	12.6	62.3	33.3
Total	Persons at risk
	Deaths
	Death rate (%)

g) Hypothesize what type of situation might result in such death rate patterns. What closed population could these data be from?

Question 3:

Classify each of the following studies as one of the following study designs:

· Experimental

· Prospective cohort

· Retrospective cohort

· Case-control

· Cross-sectional

· Ecologic

a) A representative sample of patients were interviewed and asked how much they exercise each week and whether they currently have (have ever been diagnosed with) heart disease.

b) In 2015, the occurrence of cancer was identified from April 1991 and July 2002 for 50,000 troops who served in the first Gulf War (ended April 1991) and 50,000 troops who served elsewhere during the same period. None of the troops in either group had ever been diagnosed with cancer before April 1991.

c) Persons diagnosed with new-onset Lyme disease were asked how often they walk through woods, use insect repellant, wear short sleeves and pants, etc. Twice as many patients without Lyme disease from the same physician’s practice were asked the same questions, and the responses in the two groups were compared.

d) Subjects were children enrolled in a health maintenance organization. With parent permission, at 2 months, each child was randomly given one of two types of a new vaccine against rotavirus infection. Parents were called by a nurse two weeks later and asked whether the children had experienced any of a list of side effects.

e) Eight hundred (800) new cases of glaucoma were identified in 2004 using the state registry. Eight hundred (800) population-based individuals without glaucoma were identified using random digit dialing and were frequency-matched to the individuals with glaucoma on age, race, and gender. Of the 120 subjects who reported using contact lenses, 83 had glaucoma. Of those without glaucoma, 79 report using contact lenses.

f) A study that examines the incidence of lead poisoning in each of the 50 U.S. states in relation to the average exposure to lead in each state from NHANES biomonitoring data.

g) Among 4,000 male smokers and 6,000 male nonsmokers, it was determined that 280 smokers and 344 nonsmokers had macular degeneration. After following the men who did not already have macular degeneration for several years, an additional 580 smokers and 230 nonsmokers developed macular degeneration by the end of the study period.

h) Students at Wayne State University are asked in a web survey about the average time they currently spend in front of a laptop or computer and whether they currently wear prescription eyeglasses or contacts.

Question 4:

State which observational study design (case-control, retrospective cohort, prospective cohort) is best for following scenarios and provide an explanation for why you chose that study design.

a) Evaluating maternal exposures to prescription medications, illicit drugs, and environmental chemical exposure and risk of transposition of the great arteries (TGA) in newborns. The annual cumulative incidence of TGA in the U.S. is 20-30/100,000 live births, which is very rare.

b) Identifying the health effects of exposure to Agent Orange among Vietnam War veterans 30 years after exposure.

c) Evaluating genetic predisposition to polycystic ovarian syndrome, for which few causes are currently known, by testing whether hundreds of thousands of genetic markers are associated with PCOS.

Question 5:

The following graph depicts age-adjusted breast cancer death rates plotted against the total dietary fat intake for each of 39 countries.

a) Describe the trends depicted by the graph in terms of the relationship between dietary fat intake and breast cancer mortality.

b) Generate a hypothesis about the relationship between dietary fat intake and breast cancer mortality based on these data.

c) Provide an alternative explanation for the trend you described in part a, other than a true causal association between dietary fat intake and breast cancer mortality.

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