Problem Set 6-1.docx - Problem Set#6 PUBH 305 – Introduction to Epidemiology 1 Please answer the following questions Be brief you should only require

Problem Set 6-1.docx - Problem Set#6 PUBH 305 –...

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Problem Set #6 PUBH 305 – Introduction to Epidemiology 1. Please answer the following questions. Be brief, you should only require 2-3 sentences to answer these questions successfully. a. You conduct a case control study on colorectal cancer and NSAID intake. You collect cases from the Utah Cancer Registry, and recruit controls from the general population. To minimize data entry errors, you blind your data entry employees to case/control status. The case/controls were randomly mixed, so that each data entry employee entered both cases and controls (without knowing which ones). At the conclusion of your study, your study coordinator reported that the OR was calculated to be 1.8 (95% CI: 1.2 – 2.4). However, he also reported that there was an equipment error with one of the six terminals used to enter data, and approximately 10% of the total exposure data was misclassified. How do you react to this news? This is non-differential error and the exposure misclassification was similar in frequency and degree between cases and non-cases. Since non- differential error give me a conservative bias by driving my OR closer to  null, I know that my OR of 1.8 is conservative and valid. No overreaction is necessary.  b. You are conducting a case-control study on the role of smoking and gastroschisis, a rare congenital defect in the anterior abdominal wall such that the abdominal contents protrude. You identify 100 births where the newborn is diagnosed with gastroschisis, and an age- matched control of 200 healthy newborns. You ask the mothers in the study their smoking history the year prior to conception and during pregnancy. Are you concerned with potential bias? If so, what is this bias? And what is your solution to alleviate this bias? I am concerned with recall bias for moms in the control group and reporting bias for moms in the cases group. My solution to alleviate this bias is to collect information about their smoking history the year prior to conception and during pregnancy from significant others. c. You are evaluating a potentially groundbreaking screening tool for bladder cancer, one that detects cancerous cells in urine. Typically, bladder cancer is diagnosed after symptoms appear, usually pain during urination or blood in the urine. Biopsies are used to confirm diagnosis. To evaluate the screening, you compare a group screened by your new method, and a group diagnosed without your screening method. You determine that 5-year survival rates for patients screened with your new tool have significantly higher 5-year survival than those who did not. You conclude that your new tool is a highly effective screening tool that will improve survival. Is this a correct conclusion?
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  • Fall '17
  • Epidemiology, Case-control study

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