Epidemiology homework


Epidemiology homework

Question 1

  1. Which study design was used to conduct this study? (ie prospective cohort, experimental, case-control, etc).

 

You are interested in examining the relationship between believing in things-that-go-bump-in-the-night and watching Supernatural on the CW Network.  You are able to determine the viewership of Supernatural from Nielsen Ratings on a state by state basis. Additionally, each of the 50 states has documentation on supernatural anxiety rates. You tabulate viewership and fear of supernatural things and then rank the states. You publish the relationship between watching Supernatural and fear of things-that-go-bump-in-the-night in a leading sci-fi journal.

Question 2

  1. Which study design was used to conduct this study? (ie prospective cohort, experimental, case-control, etc).

 

Broncoville University has received a grant to study the effect of social media and technology on physical health. You are planning a study that will recruit freshmen students in the 18 to 30 year old range and in the 30 to 50 year old range. Your researchers will follow these freshmen for the four years they will attend the University.  Data including number of days per week and intensity of physical activity, perception of the ease of using technology, and number of hours spent on social media will be collected. Other data such as course of study, number of hours of free time, and weight will also be collected.

Question 3

  1. Which study design was used to conduct this study? (ie prospective cohort, experimental, case-control, etc).

 

A research company is testing the effectiveness of a new blood pressure lowering medication. Patients with moderate and elevated blood pressure were recruited and randomized to either the new medication or a previously established blood pressure lowering medication. They were then followed over a two year time period to determine the impact the medication had on blood pressure. Other data, such as age, socio-economic status, weight, exercise patterns, and nutrition habits are also collected.

Question 4

  1. Which study design was used to conduct this study? (ie prospective cohort, experimental, case-control, etc).

 

A local health department has received a grant to study the community factors that are important in maintaining a healthy weight in the population. Four communities are recruited and mail questionnaires are sent to all residents. The survey ask questions about nutrition, physical activity, height, weight, and locations where physical activity occurs. Responses are tabulated for each community to develop a description of factors that seem important.

Question 5

  1. Which study design was used to conduct this study? (ie prospective cohort, experimental, case-control, etc).

 

The pharmaceutical company who produces Lumigan (bimatoprost), a drug formulated to treat certain medical conditions of the eye, is studying secondary effects. Lumigan was put on the market six years ago to treat glaucoma. Anecdotal reports have surfaced about people who are treating their eye conditions with Lumigan but are growing very long eyelashes. The company wants to know if there is any truth to these reports so they can apply to the FDA for marketing rights in the cosmetics industry. You identify those people still alive who received either Lumigan or a placebo medication for glaucoma during the original pre-marketing phase, seven years ago. You conduct a study comparing photographs of people at the start of the pre-marketing phase to current photos to see how eyelash loss or growth compares between those who used Lumigan to those who got the placebo.

Question 6

  1. Which study design was used to conduct this study? (ie prospective cohort, experimental, case-control, etc).

 

A university epidemiologist is interested in understanding why some patients with West Nile Virus (WNV) develop severe symptoms, such as meningitis, while the vast majority of patients infected do not. Patients with documented severe WNV outcomes were located, and then matched by age and gender to persons with documented mild  WNV outcomes. Demographic data, prior health history, medications, occupation, and underlying immune function data was collected on both groups.

Question 7

  1. A group of 5,000 students grades kindergarten through 6th grade were invited to participate in a study. Once a year, for eight consecutive years, researchers administered a survey asking questions about home life and school. The researchers were interested in examining the relationship between home and school experiences. When these data were analyzed, the researchers found that 25% of the students reported going to bed hungry at least three times per week. After the eight year study was completed, these students (who reported going to bed hungry at least three times per week) were found to be significantly more likely to report positive experiences at school compared to students who reported never or rarely going to bed hungry.
  1. What type of study is this? (0.5 pt)
  2. List three specific sources of bias in this study and three ways to overcome them. (3 pt)
  3. Would you report in your journal article and press release that going to bed hungry is good for school children because it enhances their school experiences? Why or why not? (0.5 pt)

Question 8

  1. Case-Control Calculation

 

Enter only numeric values into the answer line. Place a leading 0 before the decimal and remember to round to two decimal places. Note your answers for the next short essay question.

 

Swine Influenza (SI) is a growing concern at the local Broncoville Health Department in Lawrence, Kansas. You are working for a pharmaceutical company which is developing a human vaccine against SI. You are in charge of testing the vaccine’s effectiveness. You need to determine if one or two doses of vaccine is required to provide immunity. You field test and collect the following information about the vaccine status of persons who did and did not contract SI after getting either one or two doses of vaccine.

 

Develop a 2 x 2 table with the following information: Of the 727 cases of SI, 203 received two doses of vaccine. Of 1,239 controls, 771 received two doses of vaccine for SI. What is the likelihood of contracting SI with only one dose of vaccine?

 

  1. Calculate the incidence of persons with one dose of vaccine for SI Blank 1

 

  1. Calculate the incidence of persons with two doses of vaccine for SI Blank 2

 

  1. Calculate the odds ratio of developing SI among those with one dose of vaccine for SI Blank 3

Question 9

  1. In the previous question you were asked to calculate the odds ratio for developing SI if the person recieved one dose of vaccine.
  1. Using correct odds ratio interpretation formatting, what does this mean?
  2. What public health message would you disseminate?

Question 10

  1. 1. As sensitivity increases, specificity must … Blank 1
  1. As specificity increases, sensitivity must … Blank 2

Question 11

  1. Enter only numbers into your answer. Round to two decimal places after completing mathematical operations. Express your answer as a percent with two decimal places, but do NOT place a % sign after your answer.

St. Broncoville Regional Medical Center is evaluating whether to replace annual the current HIV blood test which is sent out to the reference laboratory with a new HIV rapid test which can be done in house. Approximately 5.5% of the 40,000 Broncoville population is HIV positive. The new HIV rapid test is 98% sensitive and 96% specific. Develop a 2 x 2 table.

 

  1. Calculate the Positive Predictive Value (PPV) for the new rapid HIV test Blank 1
  2. Calculate the Negative Predictive Value (NPV) for the new rapid HIV test Blank 2

4 points

Question 12

In the previous question you were asked to calculate the positive and negative predictive values of a new rapid HIV test. Interpret your answer.

 

Is this a good test? Would you recommend the new test be used at St. Broncoville Regional Medical Center? Why or why not? (be specific using the numeric values from the previous question to support your recommendations)

 

Question 13

  1. Sensitivity/Specificity/PPV/NPV calculation

 

Enter only numbers into your answer. Round to two decimal places after completing mathematical operations. Express your answer as a percent with two decimal places, but do NOT place a % sign after your answer.

 

St. Broncoville Regional Medical Center is evaluating whether to replace annual colonoscopies with a new fecal occult blood (FOB) test to rule out colon cancer. Colonoscopies are considered the gold standard and cost approximately $1,000 each. The new test kit takes five minutes and costs $5.00.A board composed of administrators, nurses, general health practitioner MD’s, and Gastroenterologist MD specialists met and evaluated 5,000 patient charts. These patients received first the new FOB test followed by a colonoscopy. The board found that of the 1,110 people who were truly positive for colon cancer and confirmed by the gold standard colonoscopy, the FOB test correctly identified 678 as truly positive. Of the 3,890 patients who did not have colon cancer and confirmed by the gold standard colonoscopy, the FOB test correctly identified 985 as truly negative. Develop a 2 x 2 table.

 

  1. Calculate the Positive Predictive Value (PPV) for the new test kit Blank 1
  2. Calculate the Negative Predictive Value (NPV) for the new test kit Blank 2
  3. Calculate the sensitivity of the new test kit Blank 3
  4. Calculate the specificity of the new test kit Blank 4

Question 14

  1. In the previous question you were asked to calculate the positive and negative predictive values, sensitivity, and specificity of the FOB test versus a colonoscopy. Interpret your answer.

 

Is this a good test? Would you recommend the FOB test replace colonoscopies to rule out colon cancer at St. Broncoville Regional Medical Center? Why or why not? (be specific using the numeric values from the previous question to support your recommendations)

 

Question 15

  1. Enter only numbers into your answer. Round to two decimal places after completing mathematical operations. Round to two significant digits. Place a leading 0 in front of the decimal if you answer is not a whole number.

Part A:

You are conducting a cohort study of low birth weight in babies after a non-eventful pregnancy. You are interested in examining numerous variables including sex of the baby and mothers drinking status during pregnancy. Below is a table showing the association between sex of the baby and low birth weights.

  1. Calculate the incidence of low birth weight in female babies Blank 1
  2. Calculate the incidence of low birth weight in male babies Blank 2
  3. Calculate crude relative risk of being low birth weight if the baby is female. Blank 3
  Low Birth Weight Normal Birth Weight Total
Female Babies 85 259 344
Male Babies 59 219 278
Total 144 478 622

 

Part B:

You are interested in exploring if the mother’s alcohol drinking status during pregnancy is a confounder and/or an effect modifier. Using the two tables below, calculate the stratum specific relative risks for women who drank during pregnancy versus women who did not drink during pregnancy.

  1. From the table below, calculate the stratum specific relative risk for female babies whose mothers drank Blank 4
Mothers Who Drank During Pregnancy
  Low Birth Weight Normal Birth Weight Total
Female Babies 73 51 124
Male Babies 21 62 83
Total 94 113 207

 

  1. From the table below, calculate the stratum specific relative risk for female babies whose mothers did not drinkBlank 5
Mothers Who Did NOT Drink During Pregnancy
  Low Birth Weight Normal Birth Weight Total
Female Babies 31 121 152
Male Babies 19 129 148
Total 50 250 300

 

  1. Is drinking status during pregnancy a confounder? YES or NO (all capitalized) Blank 6
  2. Is drinking status during pregnancy an effect modifier? YES or NO (all capitalized Blank 7

Question 16

  1. In the previous question, you were asked to calculate the relationship between gender, low birth weight, and mother’s drinking status during pregnancy.
  1. Interpret the crude relative risk. What does it mean?
  2. Explain why alcohol consumption is or is not a confounder
  3. Explain why alcohol consumption is or is not an effect modifier.
  4. What other statistical measure(s) might be needed to evaluate the relationship between gender, mother’s alcohol consumption during pregnancy, and low birth weight?

Question 17

  1. Enter only numbers into your answer. Round to two decimal places after completing mathematical operations. Round to two signficant digits. Place a leading 0 in front of the decimal.

.

Recent research shows a sharp increase in childhood diabetes. You are an epidemiologist in Lebanon, Kansas studying the relationship between childhood diabetes and obesity. You conduct a case-control study and were able to locate 500 cases of diabetes from medical records, then matched 1500 children based on age (three to 18 years old), weight-to-height ratio, gender, and residence. Use the following tables to calculate your data.

.

  1. Calculate the crude odds ratio of having diabetes in children who are obese Blank 1

.

 

Obesity and Diabetes

 

  Cases Controls  
Obese 357 774 1131
Normal Weight 143 726 869
  500 1500 2000

.

In 2015, the US Department of Agriculture changed school nutrition standards and the plan is to phase these new standards into Lebanon, Kansas public schools over the next three years. The new standards include healthier snack choices, decreasing starchy vegetables, decreasing sodium, increasing whole grains, and the establishment of core calorie minimums and maximums. However, in 2005, Lebanon, Kansas private schools made these changes to their school lunch program. In particular, Lebanon, Kansas private schools began locally sourcing food, offering vegetarian choices, increased healthy whole-food snacks, and eliminated trans-fats, fried foods and vending machines. Knowing this, you wonder if attending private school, with healthier school lunch choices, could be a confounder or an effect modifier. Use the tables below to calculate your data.

.

  1. Calculate the stratum specific odds ratiofor private school Blank 2

.

 

Private School Diabetes Data

 

  Cases Controls  
Obese 21 168 189
Normal Weight 24 287 311
  45 455 500

.

. 3. Calculate the stratum specific odds ratio for public school Blank 3

.

 

Public School Diabetes Data

 

  Cases Controls  
Obese 301 460 761
Normal Weight 154 585 739
  455 1045 1500

.

  1. Is school type (public versus private) a confounder? Answer YES or NO (all capitalized) Blank 4

.

. 5. Is school type an effect modifier? Answer YES or NO (all capitalized) Blank 5

Question 18

  1. In the previous question, you were asked to calculate the relationship between birth weight obesity, diabetes, and public/private school attendance.
  1. Interpret the crude odds ratio. What does this mean? What is the public health message?
  2. Explain why private school attendance is or is not a confounder.
  3. Exlplain why private school attendance is or is not an effect modifier.
  4. Using the solutions to the previous question, explain why private school is/is not a confounder and why type of school attended is/is not an effect modifier.

Question 19

  1. The Boondock Saints (BDS), Connor and Murphy MacManus, are brothers who fight evil, the corrupt, and the worst criminal elements. It has been postulated that they should be in every American city. The brothers have proven they can prevent and control crime with the assistance of law enforcement. A retrospective cohort study was conducted in the US over the last 15 years evaluating the relationship between crime statistics and the Boondock Saints’ arrival in the city.

1000 US cities were studied. Of the 357 cities with lower crime rates, 45 experienced a visit by the Boondock Saints. Of the 643 cities with high crime rates, the Boondock Saints visited 551. Develop a 2 x 2 table. What is the likelihood of the Saints brothers visiting a city with low crime rates?

Enter only numeric values into the answer line. Place a leading 0 before the decimal and remember to round to two decimal places. Note your answers for the next short essay question.

  1. Calculate the incidence of the Boondock Saints coming to a city with low crime rates Blank 1
  2. Calculate the incidence of the Boondock Saints coming to a city with high crime rates Blank 2
  3. Calculate the relative risk of the Boondock Saints coming to a city with low crime rates. Blank 3

 

Question 20

  1. In the previous question, you are asked to calculate the relative risk of the Boondock Saints visiting a city with lower crime statistics. Using correct relative risk interpretation formatting, what does this mean? What is the public health message if you live in a city with low crime rates? Conversely, what does it mean if you live in a city with high crime rates?

Extra credit (2 points) Why do you think the Saints brothers visited cities with lower crime rates? Should the Boondock Saints be in every American city? If so, why or why not? (If you have not seen the movie, just answer the questions. If you have seen the movie, state your opinion– you are allowed to be funny and/or politically incorrect.)

Question 21

  1. An evil genius, with a plan of world domination, decides to test the ability of his new super-genetically modified Zombie Apocalypse virus (ZAV) to infect the people of Broncoville. He kidnapped 4,000 Broncoville Tax Board auditors. The evil genius placed half of the auditors in a room where ZAV is flowing through the air-conditioning (aerosolized ZAV) and the other half of the auditors were placed in a compound where ZAV is in the drinking water (water ZAV). (No Tax Board auditors were actually harmed in this experiment)

Develop a 2 x 2 table with the following information: Of the 2,000 auditors who were in the room with the aerosolized ZAV, 751 developed the disease. Of the 2,000 auditors who drank the ZAV in water, 243 developed ZAV.

Enter only numeric values into the answer line. Place a leading 0 before the decimal if your answer is not a whole number and remember to round to two decimal places. Note your answers for the next short essay questions.

    1. Calculate the incidence for auditors exposed to aerosolized ZAV Blank 1
    2. Calculate the incidence for auditors exposed to water-borne ZAV Blank 2
    3. Calculate the relative risk of developing ZAV among aerosolized auditors Blank 3

Question 22

  1. In the previous question you were asked to calculate the relative risk for aerosolized ZAV. Interpret this result. What does it mean? What public health message would you disseminate?

 

Question 23

In the previous two questions you have been discussing aerosolized ZAV versus water-borne ZAV. Is this an effective path to world domination? Why or why not? (You are allowed to be funny and/or politically incorrect.)

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