In a case control study of the association between obesity and late onset menopause, you think that women who are and are not obese are equally as likely to misreport that they had late onset menopause.
a. What type of misclassification is this? Be sure to state whether it is differential or nondifferential, AND whether it is misclassification of the exposure or the disease in your response
b. How would this misclassification bias the OR you calculate using your study findings? Be sure to state whether you think it would bias the OR toward or away from the null value of 1 in your response
In a case control study of the association between obesity and late onset menopause, you think...
A case-control study was conducted to examine the association between a high fat diet and coronary artery disease. Subjects with physician diagnosed heart disease and controls without heart disease are recruited and asked to complete questionnaires about their dietary habits in order to categorize them as having diets with high fat content or not. This situation is more likely to generate which type of bias: a. non-differential misclassification b. differential misclassification c. selection bias d. none of the above
You have conducted a case-control study to determine the association between exposure to lead and development of cognitive disorders. Exposure data were collected from measuring blood samples and outcomes data from medical records. Participants were randomly selected to be included into the study. The investigator who obtained the exposures and outcomes data was blinded to the outcome status of the participant. In your study, you find an OR of 1.01. However, the actual association between exposure to lead and cognitive...
An investigator conducted a case-control study in 1000 participants (500 cases and 500 controls) to examine the association between childhood head trauma (exposure) and Parkinson’s disease(outcome). Information on head trauma was self-reported by study participants. Cases were able to correctly report exposure to head trauma 96% of the time, while controls correctly reported exposure to head trauma 80% of the time. Cases and controls correctly reported no exposure to head trauma 96% and 98% of the time, respectively. The truth(which...
A case-control study was conducted to determine the association between smoking and coronary heart disease. The investigators found an odds ratio of 1.8 for coronary heart disease among subjects who smoked compared to those who didn’t smoke. The 95% confidence interval for this odds ratio was 0.8-4.3 and the P-value was 0.10. 1. State in words your interpretation of the odds ratio. 2. State in words your interpretation of the 95% confidence interval. 3. State in words your interpretation of...
1. Describe: a) a control subject in a case-control study, 2. and b) a control subject in an experiment. You may want to describe their disease and/or exposure status. 3. Does "validity" indicate that a test or an instrument is accurate/correct? a. Yes b. No 4. The Healthy Worker Effect is an epidemiological concept that has shown that as a group, people who are employed are healthier than the general population. Because of this researchers must be alert to the...
Researchers are planning to conduct a case-control study of the association between an occupational exposure and a health outcome. The researchers plan to study exposed workers from one factory and compare them with unexposed retirees who have never worked in a factory. A reviewer of the research proposal is worried about selection bias and in particular about the possibility of the healthy worker effect. Which of the following best represents the reviewer's concern? a. Retirees should not be compared to...
For the first six issues below, cite which study is best to use (case-control or cohort study). For the last 3 types of bias, cite which study is less likely to have that particular type of bias (case-control or cohort) Answer 26 1) Study a rare discase 2) Study a rare exposure 3) Study multiple exposures 4) Study multiple outcomes 5) Study progression of the illness 6) Calculate disease rates 7) Recall bias 8) Loss to follow-up 9) Selection bias...
27. Interpret your findings that you calculated in # 26. study design. c. experimental 28. The well-known Framingham Study employs the a case-control b. cohort 20. When selecting control subjects for a case-control study, the control group members should (select the best answer): resemble the case subjects b. have already had the disease of interest have had no opportunity to be exposed to the disease. be very ill hospital patients 30. True False W hen using the cohort study design...
9. When you desire to study the effects of a rare exposure on a disease using observational methods, you would optimally employ the type of study design. Remember you would likely need to conduct your study in a place where the exposure occurs. cohort b ase-control 10. Another name for a retrospective study is an) study b. cohort e experimental 11. You have completed a year long study of the effectiveness of a reading program among second graders. At the...
You are conducting a large concurrent cohort study evaluating the association between drinking alcohol and the likelihood of contracting an STD over the course of a year. After data collection has been completed, your 2 x 2 table looks like the table below (these numbers are hypothetical): Original Data Alcohol No alcohol Total STD 295 160 455 No STD 2,116 929 6,045 Total 2,411 4,089 6,500 3. Alcohol and substance abuse are commonly underreported, as are STDs, due to social...