University of Texas Health Science Assignment | PHM2612 Module 10 Cohort Studies Correct Answers

University of Texas Health Science Assignment PHM2612 Module 10 Cohort Studies Correct Answers 1 Assignment PHM2612 Module 10. Cohort Studies Complete this quiz on Canvas by or before the due date on the course calendar. Please note that you will only have one attempt to complete the quiz; however, there is no time limit. You may use this document to answer the questions prior to submitting your answers on Canvas. For questions requiring calculations, keep 5 decimal places for intermediate steps and round your final answers to two decimal places. (100 points) 1. Cohort studies compare incidence rates of exposure between disease groups and groups without the disease. (2 points) A. True B. False 2. In a study where the goal is to evaluate whether a given occupational group has a higher risk of a given outcome, it would be appropriate to select construction workers as the exposure group and people from the general population as the non-exposure group is appropriate. (2 points) A. True B. False 3. Relative risk in a cohort study is the ratio of the risk of exposure among diseased individuals to the risk of exposure among those without the disease (2 points) A. True B. False 4. What are advantages of the cohort study design? Select all that apply (2 points)  It can provide a direct estimate of risk.  It is open to several types of selection bias.  It is useful for assessing the temporal relationship between exposure and outcome.  It is generally less expensive and less time consuming than other study designs. 5. Participants in a cohort study can be selected based on their _________ status. (2 points) A. Disease B. Outcome C. Morbidity status D. None of the above 6. Which of the following does not describe “attrition bias”? (Check all that apply) (2 points)2  A type of selection bias in which study participants become missing at some point during the follow-up period of a study in ways that are related to the exposure and outcome under study  A type of information bias in which a person’s responses are affected by his/her socioeconomic status.  A type of information bias in which study participants become missing at some point during the follow-up period of a study.  An advantage associated with the cohort study design. 7. What is one important advantage of the cohort study design? (2 points) A. It can only provide an indirect estimate of risk. B. Not useful for rare outcomes C. It is useful for assessing the temporal relationship between exposure and outcome. D. It is generally less expensive and less time-consuming than other study designs. Use the following information to answer questions 8-14. Research suggests that there is a dose response relationship between sugar intake and sleep disorders. Suppose that the table shown below was developed using data from a 10-year cohort study. Participants were categorized based on their sugar intake levels and followed over time to see if they developed a sleep disorder. The referent group was those who did not consume sugar. Exposure Status New Cases of sleep disorders Person-Years of Observation No sugar intake Occasional sugar intake Frequent sugar intake 8. Calculate the incidence density (rate) of sleep disorders per 1,000 person-years of observation in the referent group (i.e., the unexposed). (2 points) A. 19.69 B. 23.91 C. 17.94 D. 14.86 9. Calculate the incidence density rate ratio (also called the incidence rate ratio – IRR) for the frequent sugar intake group compared to the referent group (i.e., the unexposed). Don’t forget to keep 5 digits for intermediate steps. (2 points)3 A. 1.61 B. 1.21 C. 1.33 D. 0.82 10. Based on your answer to the previous question, would you conclude that a high level of sugar intake is a protective or harmful factor for the risk of sleep disorders in this population? (2 points) A. Protective factor B. Harmful factor C. Neither harmful nor protective as the IRR is not significantly different from the null of 1.0. 11. Suppose in the question above, you want to compare any sugar intake against no sugar intake, and you know the number of people in each exposure group as seen in the table below. What is the risk (incidence proportion) in those who ingest any sugar? Report your answer with 5 decimal places (2 points). .18467 Exposure Status New Cases of sleep disorders Total number of persons observed ANY sugar intake 855 4630 No sugar intake 203 1780 12. What is the risk (incidence proportion) in those who do not ingest any sugar? Report your answer with 5 decimal places (3 points) 203/1780= .11404 13. What proportion of cases with sleep disorders among those who ingest any sugar is attributable to any sugar intake? Hint: calculate the attributable risk proportion (ARP or %AR) in the exposed compared to the no sugar intake group (Please report your answer as a percentage with two decimal places. You do not need to include the % symbol when entering the answer in Canvas). (2 points) ______7.06_____ % 14. Assume the answer you calculated above was 60.00%. Which of the following is the correct interpretation of the percent attributable risk in the exposed? (2 points)4 A. Assuming that any sugar intake can cause sleep disorders, 60% of people who ingest any sugar will develop sleep disorders. B. Assuming that any sugar intake can cause sleep disorders, 60% of the cases who have sleep disorders in the population is attributable to any sugar intake C. Assuming that any sugar intake can cause sleep disorders, 60% of cases with sleep disorders among any sugar users is attributable to their sugar ingestion. D. Assuming that any sugar intake can cause sleep disorders, those who ingest any sugar have a 60% increased risk of sleep disorders compared to those that do not ingest any sugar 15. A major advantage of cohort studies over case-control studies with respect to the role of a suspected risk factor in the etiology of a disease is that: (2 points) A. They can be done on a double-blind basis. B. They allow for the calculation of odds ratios. C. They permit direct estimation of the risk of disease in the exposed group D. They take less time and are less costly. E. It is easier to obtain controls who are not exposed to the suspected risk factor. 16. Which of the following is a definition of cohort effect (2 points) A. Variations in time, in one or more characteristics of a particular group of individuals that shared a major life experience. B. The effect of the exposure on the outcome C. The unequal loss of participants due to follow-up in one of the exposure groups D. When group characteristics are used to describe individual risks for those in the group Use the following information to answer questions 17 and 18. A ten-year prospective cohort study has just been completed. The study was designed to assess the association between UV exposure and morbidity and mortality resulting from measles. The RR for the incidence of measles (morbidity) was 1.25 and the RR for measles mortality was 2.00, where no UV exposure is the referent/reference group. 17. Which statement is correct about this study? (Check all that apply) (2 points)5  a. A cohort study is not a good design to study this association because measles is a very common disease.  b. A cohort study is an appropriate study design because the association between one exposure and two different outcomes is being considered.  c. One of the problems that this study may have is the loss to follow-up of participants during the ten-year period.  d. One of the problems that this study may have is the inability to assess temporality. 18. Suppose another researcher calculated the RR to be 0.37 for measles morbidity and 0.56 for measles mortality. Which would their conclusion be? (2 points) A. UV exposure is a stronger protective factor for measles morbidity than it is a protective risk factor for measles mortality. B. UV exposure is a stronger harmful factor for measles morbidity than it is a harmful risk factor for measles mortality. C. UV exposure is a stronger protective factor for measles mortality than it is a protective risk factor for measles morbidity. D. UV exposure is a stronger harmful factor for measles mortality than it is a harmful risk factor for measles morbidity. 19. Cohort study is to risk ratio as: (2 points) A. Cross-sectional study is to prevalence ratio B. Ecologic fallacy is to cross-sectional study C. Case-control study is to odds of exposure ratio D. Case-control study is to odds of disease ratio E. Genetic study is to ecological study F. Both A and C G. Both A and D 20. Which categories of bias must be avoided or considered when conducting cohort studies? (2 points) A. Information bias B. Cohort effect C. Selection bias D. Both A and C Use the following passage for questions 21-28. The hypothesis that men in high stress jobs have an increased risk of developing coronary heart disease (CHD) has been evaluated for decades. This hypothesis was tested in a group of 15,000 men of Japanese ancestry in Hawaii who were6 followed in an 18-year study. The study was initiated in 2004 and follow-up by the researchers lasted through summer of 2023. For the duration of the study, 7900 were free of CHD, stroke and cancer, while 7,100 had incident CHD. Of the 7300 men with higher stress jobs, 4200 of them developed CHD. Of the men with lower stress jobs, 2,900 of them developed CHD. 21. Is this a cohort study design? If yes, what type of cohort study is it? (2 points) A. No, it is a case-control study design. B. No, it is a cross-sectional study design. C. Yes, it is a prospective cohort study. D. Yes, it is a retrospective cohort study. 22. Construct and label the appropriate 2x2 table using the information above. Don’t forget your marginal totals. Note: You may copy and paste your table from Word onto canvas. (10 points; 1 point for each numeric cell; ¼ point for each label) Exposure Status CHD CHD does not develop Total High Stress Job 4200 3,100 7,300 No High Stress Job 2,900 4,800 7,700 7,100 7,900 15,000 23. Calculate the risk ratio (relative risk) of developing CHD for the high stress group as compared to the low stress group. Keep 5 decimal places in intermediate steps, and round your final answer to two decimal places. (3 points) 4,200/7300=.57534 2,900/7,700=.37662 1.537 24. Let’s assume the risk ratio (relative risk) calculated above is 1.12. Choose the correct interpretation(s). Check all that apply. (2 points) Men in higher stress jobs had 1.12 more chances of developing CHD when compared to men in lower stress jobs. Those with high-risk jobs have 1.12 times the rate of developing CHD when compared to non-high-risk jobs. Men with high stress jobs had 1.12 times the risk of developing CHD compared to those with low stress jobs. The risk of developing CHD among men with high stress jobs was 1.12 times the risk of developing CHD among those with low stress jobs. The risk of developing CHD among men with high stress jobs is 12% higher than the risk of developing CHD among those with low stress jobs. Men with low stress jobs had 1.12 the risk of developing CHD compared to those with high stress jobs. 25. Calculate the risk ratio (relative risk) of developing CHD for the low stress group as compared to the high stress group. Keep 5 decimal places in intermediate steps, and round your final answer to two decimal places. (3 points) 0.65 26. In one sentence, interpret your result for the risk ratio (relative risk) of developing CHD in the low stress group from the previous question. (3 points) Low stress group has .65 times the risk of developing CHD compared to high stress group. 27. Calculate the odds ratio of developing CHD for the low stress group as compared to the high stress group. Keep 5 decimal places in intermediate steps, and round your final answer to two decimal places. (2 points) (2900/4800)/(4200/3100)= .60417/1.35484=.458 28. In one sentence, using the number you calculated above, interpret your result from the previous question. (2 points) The odds of developing CHD among the low stress group are .45 times the odds of CHD among the high stress group. 29. Match the following excerpts with the appropriate epidemiologic study design. (Study design may be used more than once or none at all.) (8 points) Excerpt Study Design __C__ Researchers conduct a study that involves a single telephone interview with a random sample of 2,000 women who gave birth in Hillsborough County anytime during 1998. They question the women about any congenital birth defects in their babies born during 1998 and on whether they were exposed to cigarette smoke during the first trimester of their pregnancy. A. Ecological B. Retrospective Cohort C. Cross-Sectional D. Prospective Cohort E. Case-Control __A_ Researchers conducted a population-based study aimed at testing the hypothesis that air pollution from jet fuel increases the risk of cancer. They compared the incidence of cancer in areas neighboring the Schiphol-Airport (exposed) and control areas with higher air quality. Cancer incidence was estimated by the different postal code areas. __B__ To assess the possible carcinogenic effects of radio-frequency signals emitted by cellular telephones, an investigator conducted a study in Denmark. The two companies that operate cellular telephone networks in Denmark furnished names and addresses for all 522,914 of their individual clients during the years from 1982 – 1995. The investigators then matched these records to the Danish Central Population Register, which contains a unique 10-digit number for each person and information on vital status and emigration. After removing non-matches, duplicates, persons outside the study’s age limits or geographic catchment area, and persons who asked not to be studied, 420,095 cellular telephone subscribers remained and formed the exposed and non-exposed cohort. To determine who had developed cancer during the same years (1982- 1995), they accessed a pre-existing registry with vital statistics data. __E_ Researchers used the discharge records from 1997 for the Tampa General’s nursery. Here they identified a random sample of 50 babies born with congenital birth defects and a random sample of 200 babies born without congenital birth defects. Then they interviewed the mother of each of these babies over the phone, to ask about exposure to video display terminals during9 the first trimester of pregnancy. 30. The Framingham Heart Study (also see Chapter 8, Gordis, “Examples of cohort studies”) was designed to test multiple hypotheses regarding cardiovascular disease. Which of the following were some of these hypotheses? Check all that apply (2 points)  Elevated blood cholesterol level is associated with an increased risk of CHD.  Persons with hypertension develop CHD at a greater rate than those who are normotensive.  Increased physical activity is associated with a decrease in CHD development.  The incidence of coronary heart disease (CHD) decreases with age. It occurs later and less frequently in males. After reading the article by Michels et al. (2002), answer questions 31-41. 31. What kind of study is Coffee, Tea, and Caffeine Consumption and Breast Cancer Incidence in a Cohort of Swedish Women conducted by Michels et al in 2002? (2 points) A. Prospective Cohort B. Case control C. Cross-sectional D. Retrospective Cohort 32. What was the source of information that was used to identify the cases in this study? Note: we are not asking for the definition of a case here nor are we asking you to provide what statistic was used (2 points) Swedish Mammography Screening Cohort 33. Which of the following statements is/are false about the study conducted by Michels et al. (2002)? Check all that apply (2 points)  A weakness to the Cohort study design is that variability in the exposure measurement reduced the authors’ ability to establish temporality.  There was no significant association between coffee consumption and risk of breast cancer.  Overall, caffeine was found to be significantly associated with a decreased risk of breast cancer among Swedish women.  There was a significant risk associated with the development of breast cancer and black tea consumption in Swedish women.10 34. Read the Results section of the paper and use the data provided there to determine the cumulative incidence (incidence proportion) of breast cancer for all women included in the study. Write your answer per 100 women and round your final answer to 2 decimal places. (2 points) 1271/59,036= 2.15 35. Read the Results section of the paper and use the data provided there to determine the incidence density (incidence rate) of breast cancer for all women included in the study. Write your answer per 1,000 person-years and round your final answer to 2 decimal places. (2 points) 1271/508,267= 2.5 36. Review Table 1. Given the data provided in the table, what measure of association can be calculated to establish the strength of the association between coffee consumption and breast cancer? (2 points) A. Prevalence Ratio B. Odds Ratio C. Risk Ratio (ratio of incidence proportions) D. Rate Ratio 37. Calculate the appropriate measure you indicated above, comparing those who drank 2-3 cups of coffee per day to those who drank 1 cup of coffee per day . Consider those that drank 1 cup of coffee per day as the referent group and round your final answer to 2 decimal places (any intermediate steps should be rounded to 5 decimal places). (3 points) 1.09 38. Interpret the measures of association you calculated above. (3 points) Subjects who had 2-3 cups of coffee per day had 1.09 times the risk of developing breast cancer compared to those who drink 1 cup a day.11 39. In their discussion the authors review the previous literature conducted on this particular exposure—outcome pair and write “of at least 22 case-control studies on coffee or caffeine consumption, a statistically significant association was found in only two studies, one reporting an increased risk and one an inversion association. Among size cohort studies conducted before ours, no significant overall association was observed” (page 25). Which of Bradford Hill’s causal guidelines is best addressed here? (2 points) A. Temporality B. Consistency C. Biological plausibility D. Biological gradient E. Strength of the Association 40. In their discussion, the authors write “measurement error is inherent in questionnairebased dietary assessment; thus, attenuation of any association has to be considered” (page 25). What type of bias are the authors acknowledging may have occurred here: selection or information bias? (2 points) A. Selection bias B. Information bias C. Confounding bias D. Lead time bias 41. In their discussion, the authors write, “In the Nurses Health Study, women who reported drinking four or more cups of tea per day had a relative risk of breast cancer of 0.7 (95% CI 0.5 – 1.0) compared to women drinking one cup or less. Does the point estimate of 0.7 suggest that tea was a protective factor or a risk factor for breast cancer in the Nurses Health Study? (2 points) A. Harmful risk factor for breast cancer B. Protective factor against breast cancer