PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022)

PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) Q UE S TI O N 1 1. If the incide nce rate of a very serious disease is 25/100,000 person-years and the prevale nce of this disease in the population is 75/100,000, what is the average survival time of individuals who contract this disease? a 1 year . b 3 years . c 3 . months d 4 . months Q UE S TI O N 2 5 points 1. A report of a clinical trial of a new drug versus a placebo noted that the new drug gave a higher proportion of successes than did the placebo (70% versus 40%). The report ended with the statement that the p value associated with this finding was equal to 0.05. This means that 5 out of 100 patients did not benefit from the new drug. True False Q UE S TI O N 3 5 points 1. When a new prevention measure for a disease is developed, both the incidence and prevale nce of the disease will decrease over the long term. True False Q UE S TI O N 4 5 points 1. What can randomization do that no other method to control confounding can do? a It can control for known confounders . b It can assure there is no bias in the study results . c It can automatically assess effect modification . d It can prevent self-selection of subjects into the groups PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) . being compared Q UE S TI O N 5 5 points 1. If an exposure has no association with an outcome, then the attributable proportion in the exposed is 1. True False Q UE S TI O N 6 5 points 1. A cohort study of coffee drinking and anxiety was conducted at a univers ity campus. There were a total of 30,000 freshmen who participated. 10,000 were coffee drinkers and 20,000 were not. Of the coffee drinkers, 500 developed anxiety during the 4 year follow-up period. Of the non-coffee drinkers, 200 develope d anxiety during the same time period. Assume that no one in the population died or was lost during the followup period. Calculate the risk difference using the given data. The numeric value of the risk difference is… a 6.0 % . b 4.0 % . c 5.0 % . d None of the . above Q UE S TI O N 7 5 points 1. Consider the situation in a cohort study where the crude risk ratio is 2.5. The data are then divided into two groups. In the first group the group-specific risk ratio is 1.0, and the second group’s risk ratio is 4.0. Which of the following is present? a Positive confounding . b Negative confounding . c No effect modification or . confounding d Effect modification, confounding . irrelevant Q UE S TI O N 8 5 points PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) 1. If an exposure has no association with an outcome, then the odds ratio will be 1. True False Q UE S TI O N 9 5 points 1. Suppose that a study on obesity and cancer contained the follow ing statement: Many epidemiological studies conducted in the U.S. and abroad have also found that a high body mass index increases the risk of cancer mortality. Which one of Hill’s guidelines for assessing causation is supported by this statement? Temporality Biological gradie nt/doseresponse Consiste ncy Strength of association Q UE S TI O N 1 0 5 points 1. A cohort study of coffee drinking and anxiety was conducted at a univers ity campus. There were a total of 30,000 freshmen who participated. 10,000 were coffee drinkers and 20,000 were not. Of the coffee drinkers, 500 developed anxiety during the 4 year follow-up period. Of the non-coffee drinkers, 200 develope d anxiety during the same time period. Assume that no one in the population died or was lost during the followup period. Which of the following is the correct interpretation of a risk ratio calculated from this study? a Coffee drinkers are “x” times as likely to develop anxiety as compared to non- . coffee drinkers. b The excess risk of anxiety among coffee drinkers is “x” as compared to non- . coffee drinkers. c The excess risk of anxiety among the entire freshmen population is “x” . d None of the above . PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) 5 points Q UE S TI O N 1 1 1. In January, 2001 forty heterosexual hemophiliac patients (all males) were asked to participate in a 3 year prospective study . The men were to undergo an interview, physical examination, and blood testing for HIV status every 6 months for 3 years. Among the 40 subjects there were 30 who were seronegative and healthy for the entire duration of the study, and all of these were followed for the entire 3 years. During the initial screening, 2 of the men were found to already be HIV+, although none of them had clinical signs of AIDS. The table below describes the 10 subjects who either tested HIV positive, or became lost to follow-up, or already were HIV positive at the start of the study. Legend: = found to be HIV+ at the very beginning of the interval observation period = lost to follow-up HIV+ ? ************* Follow-up ********************** Subject # Initial ng Screeni Jan. 2001 June 2001 Jan. 2002 June 2002 Jan. 2003 June 2003 1 --------- --------- --------- --------- --------- HIV+-- 2 --------- --------- --------- --------- --------- ? 3 --------- --------- HIV+-- --------- --------- --------- 4 --------- ? 5 --------- --------- --------- ? 6 --------- --------- --------- --------- --------- ? 7 --------- HIV+-- --------- --------- --------- --------- 8 --------- --------- --------- --------- --------- ? 9 HIV+ --------- --------- --------- --------- --------- --------- 10 HIV+ --------- --------- --------- --------- --------- ? What was the cumulative incidence of seropos itivity (HIV+) during the 3 year study? a 5/4 . 0 b 3/1 . 0 c 5/3 . 5 d 3/3 . 8 5 points Q UE S TI O N 1 2 1. Use your knowledge of the sufficient- compone nt causal model to choose the best answer to complete this sentence: Blocking the action of a cause will prevent all cases of disease by all causal mechanisms. PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) Sufficient Compone nt Necessar y Insufficie nt Q UE S TI O N 1 3 5 points 1. A case-control study was conducted to evaluate the relationship between aspirin use and the risk of colon cancer. 2,000 cases and 2,000 controls were enrolled in the study. 1,800 of the cases reported using aspirin in the past while 1,200 of the controls reported using aspirin in the past. What measure of association should be calculated to determine the strength of the relationship between aspirin and colon cancer? a Rate ratio . b Risk ratio . c Odds ratio . d Attributable . risk 5 points Q UE S TI O N 1 4 1. In January, 2001 forty heterosexual hemophiliac patients (all males) were asked to participate in a 3 year prospective study . The men were to undergo an interview, physical examination, and blood testing for HIV status every 6 months for 3 years. Among the 40 subjects there were 30 who were seronegative and healthy for the entire duration of the study, and all of these were followed for the entire 3 years. During the initial screening, 2 of the men were found to already be HIV+, although none of them had clinical signs of AIDS. The table below describes the 10 subjects who either tested HIV positive, or became lost to follow-up, or already were HIV positive at the start of the study. Legend: PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) HIV+ = found to be HIV+ at the very beginning of the interval observation period ? = lost to follow-up ************* Follow-up ********************** Subject # Initial ng Screeni Jan. 2001 June 2001 Jan. 2002 June 2002 Jan. 2003 June 2003 1 --------- --------- --------- --------- --------- HIV+-- 2 --------- --------- --------- --------- --------- ? 3 --------- --------- HIV+-- --------- --------- --------- 4 --------- ? 5 --------- --------- --------- ? 6 --------- --------- --------- --------- --------- ? 7 --------- HIV+-- --------- --------- --------- --------- 8 --------- --------- --------- --------- --------- ? 9 HIV+ --------- --------- --------- --------- --------- --------- 10 HIV+ --------- --------- --------- --------- --------- ? What were the total person-months at risk during the study? a 162 . b 1,242 . c 1,080 . d It is not possible to calculate total person-months with the . information given. 5 points Q UE S TI O N 1 5 1. Information bias occurs a after the subjects have entered the . study. b before the subjects have entered . the study. c Both of the above . d None of the above . Q UE S TI O N 1 6 5 points 1. Which of the follow ing depends on the rate at which new cases develop as well as the duration that the cases have the disease? PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) a Incidenc . e b Prevalen . ce c Mortality . d Morbidity . Q UE S TI O N 1 7 5 points 1. A study followed 900,000 US adults from 1992 to 2008. At baseline, all participa nts were screened and determined to be cancer free and their body mass index (BMI) was calculated. Body mass index is a measure of obesity that is calculated using a person’s height and weight. Subjects were separated into the following groups according to their BMI: (a) normal weight, (b) slightly overweight, (c) moderately overweight and (d) greatly overweight. 57,145 deaths from cancer occurred in the population during the follow-up period. The following results were seen for men and women when the heaviest members of the cohort were compared to those with normal weight: Men: Risk ratio of cancer death = 1.5 Women: Risk ratio of cancer death = 1.6 2. 95% confidence interval = 1.1-2.1 95% confidence interval = 1.4-1.9 3. Which of the follow ing is the correct interpretation of the risk ratio given for the men? a Compared to women, men had a 50% increase d risk of cancer death. . b Compared to men of normal weight, greatly overweight men had a 50% . increased risk of cancer death. c Men who were greatly overweight were 50% less likely to die from cancer than . men of normal weight. d None of the above. . Q UE S TI O N 1 8 5 points 1. A study followed 900,000 US adults from 1992 to 2008. At baseline, all participa nts were screened and determined to be cancer free and their body mass index (BMI) was calculated. Body mass index is a measure of obesity that is calculated using a person’s height and weight. Subjects were separated into the following groups according to their BMI: (a) normal weight, (b) slightly overweight, (c) moderately overweight and (d) greatly overweight. 57,145 deaths from cancer occurred in the population during the follow-up period. What type of study is this? PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) a Cohort study . b Cross-sectional . study c Case-control . study d Ecologic study . 5 points Q UE S TI O N 1 9 1. Cigarette smoking is a of lung cancer. Suffici ent cause Necessary cause Both a sufficient and necessary cause Neither a suffic ient nor necessary cause Q UE S TI O N 2 0 5 points 1. Suppose that your company has just developed a new screening test for a disease and you are in charge of testing its validity and feasibility. You decide to evaluate the test on 1000 individuals and compare the results of the new test to the gold standard. You know the prevalence of disease in your population is 30%. The screening test gave a positive result for 292 individuals. 285 of these individuals actually had the disease on the basis of the gold standard determination. Calculate the predictive value of a positive test: a 93.7 . % b 97.6 . % c 99% . d 95% . PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) Q UE S TI O N 2 1 5 points 1. Which measure of disease frequency best describes the follow ing: the percentage of nursing home residents who have bed sores on July 1, 2012. a Prevalence . b Cumulative . incidence c Incidence rate . d None of the . above Q UE S TI O N 2 2 5 points 1. A cohort study of coffee drinking and anxiety was conducted at a univers ity campus. There were a total of 30,000 freshmen who participated. 10,000 were coffee drinkers and 20,000 were not. Of the coffee drinkers, 500 developed anxiety during the 4 year follow-up period. Of the non-coffee drinkers, 200 develope d anxiety during the same time period. Assume that no one in the population died or was lost during the followup period. Which of the following is the correct interpretation of the population risk difference calculated from this study? a Coffee drinkers are “x” times as likely to develop anxiety as compared to non- . coffee drinkers. b The excess risk of anxiety among the coffee drinkers is “x” . c The excess risk of anxiety among the entire freshmen population is “x” . d None of the above . Q UE S TI O N 2 3 5 points 1. A randomize d experimental study was conducted to evaluate the effectivene ss of a new pertussis vaccine. One thousand healthy children were randomized to receive either the new vaccine (500 children) or the old vaccine (500 children). The children were followed for two years to monitor the incidence of pertussis. At the end of the study, the risk ratio for developing pertussis was 0.5 among the children who received the new vaccine compared to children who received the old vaccine. The 95% confidence interval for this relative risk was 0.2-0.8 and the p value was 0.01. State in words your interpretation of the risk ratio. a The new vaccine was half as effective as the old vaccine in preventing . pertussis. b Children who received the old vaccine had a 50% reduced risk of developing PUBH 8035 Epidemiology: Decoding The Science Of Public Health (Spring 2022) . pertussis compared to those who received the new vaccine. c There was no statistically signif icant difference between the two vaccines. . d Children who received the new vaccine had a 50% reduced risk of developing . pertussis compared to those who received the old vaccine. Q UE S TI O N 2 4 5 points 1. A cohort study of coffee drinking and anxiety was conducted at a univers ity campus. There were a total of 30,000 freshmen who participated. 10,000 were coffee drinkers and 20,000 were not. Of the coffee drinkers, 500 developed anxiety during the 4 year follow-up period. Of the non-coffee drinkers, 200 develope d anxiety during the same time period. Assume that no one in the population died or was lost during the followup period. Which of the following is the correct interpretation of a risk difference calculated from this study? a Coffee drinkers are “x” times as likely to develop anxiety as compared to non- . coffee drinkers. b The excess risk of anxiety among the coffee drinkers is “x” as compared to . non-coffee drinkers. c The excess risk of anxiety among the entire freshmen population is “x” . d None of the above . Q UE S TI O N 2 5 5 points 1. Which measure of association is commonly used by public health officials to determine which exposures are most important to the entire population and helps prioritize prevention activities? a Risk/Rate ratio (a.k.a. relative . risk) b Risk/Rate difference . c Population risk/rate . difference d None of the above .