EPID 4400 Final Examination Preparation with complete solutions., Exams of Epidemiology

Download EPID 4400 Final Examination Preparation with complete solutions. and more Exams Epidemiology in PDF only on Docsity!

EPID 4400 Final Examination Preparation

with complete solutions

Case-fatality rate - ANSWER-Numerator - (Number of deaths from a disease) Denominator - (Number of cases of that disease) [Section 6] Exam 1 Important guidelines for evidence of a causal relationship. - ANSWER-- Dose-response relationship

• Temporal Relationship (time)
• Replication of findings
• Strength of association EXCLUSION: Effect Modificaiton [Section 5] Exam 1 If the steady state assumption is satisfied, prevalence of a disease is mathematically related to... - ANSWER-- Average duration of the disease
• Incidence of the disease [Prevalence = (incidence) x (average duration of the disease)] Exam 1 Choose rate or ratio that best describes the following statement: "At the initial examination, 31 persons aged 40 to 49 had coronary heart disease per 1,000 persons examined in this age group"
  • Age-adjusted mortality rate
  • Age-specific prevalence rate
  • Incidence rate
  • Prevalence rate
  • Standardized mortality ratio - ANSWER-Age-specific prevalence rate [This rate is distinguishable by the phrase per 1,000. The rate is broken down into an age group, which is an age-specific rate. However, no evidence of standardization is given. These are existing cases, not new cases.] Exam 1

In the classic or traditional sense, epidemiology is best defined as the study of the... - ANSWER-Distribution and determinants of health-related states or events in humans [Section 1] Exam 1 When a new treatment is developed that prevents death but does not produce recovery from a disease, the following will occur: - ANSWER-Prevalence of the disease will increase [Prevalence = (incidence) x (average duration). Prevention of death increases the average duration of disease, thus increasing prevalence.] Exam 1 A weighted average of the individual age-specific mortality rates in the study population, with the weights being the proportion of a standard population in each category, is the definition of the -Crude rate -Direct method of age-standardization -Indirect method of age-standardization -Proportionate mortality ratio -Standardized mortality ratio - ANSWER-Direct method of age-standardization [Definition of direct adjusted rate. Section 6] Exam 1 The sequence of studies in human populations typically begins with: - ANSWER-A descriptive study [Descriptive studies are hypothesis generating. The data and info collected here (especially person, place, and time) informs our analytical studies (hypothesis testing with a comparison group)] Exam 1 When calculating an age-standardized mortality ratio (SMR), what is needed? -Age-specific mortality rates in the sample (or study population) -Total number of observed deaths in the standard population -Both -Neither - ANSWER-Neither SMR = observed / expected The observed is the "number of deaths in the study population." The expected is calculated by taking age-specific rates of a standard population and applying these to the distribution of each study population. Exam 1 Which statement is not true?

• An adjusted rate is a fictional rate.
• An adjusted rate is a summary rate.
• Two states which have the same age-adjusted rates, likely have the same crude rates.
• Crude rates are helpful in determining disease burden and specific needs for services for a given population, compared with another population, regardless of size.
• The absolute magnitude of an adjusted rate depends on the standard chosen. - ANSWER-NOT TRUE -> Two states which have the same age-adjusted rates, likely have the same crude rates. [Even if two states have the same age-adjusted rates for incidence/death from a disease, the crude rates can be different as the age distribution of a population (the number of people in particular age categories) can change over time, and can be different in different geographic areas, altering the crude rates.] Exam 1 The incidence rates of a disease are three times greater in men than in women, but the prevalence rates show no sex difference. The best explanation is that: - ANSWER-The case-fatality rate for this disease is greater in men. [In order for there to be the same amount of disease (prevalence) in each sex, but more cases (greater incidence rate) occur in men, more men must die from this disease. This causes the levels of disease present in each sex to even out.] Exam 1 Age-adjusted death rates are used to: - ANSWER-Eliminate the effects of differences in the age distributions of populations in comparing death rates. [Age-adjusted death rates have been adjusted to a standardized population distribution. This eliminates the effects of differences in the age distribution of populations in comparing death rates.] Exam 1 Mortality rate - ANSWER-Numerator - (Number of deaths from a disease) Denominator - (Total population) [Section 6] Exam 1 An epidemiological study begins with 1000 patients with newly diagnosed lung cancer and 2000 healthy controls. Thereafter, the study investigators collect data on the prior exposure to radon. Which of the following types of study design best fits this description? - ANSWER-Case-control study Exam 1 The association between low birth weight and maternal smoking during pregnancy is studied by investigating a group of expectant mothers. Data on current smoking habits is obtained at the time of their first and subsequent prenatal visits and, after giving birth,

the newborn birth weight is recorded. What type of study is this? - ANSWER- Prospective Cohort Study [Study starts with exposure data (smoking habits), which makes it a COHORT study. The mothers are followed forward (into the future) through time to see the outcome (disease status) of the birth weight of their newborns.] Exam 1 Choose the rate or ratio that best describes the following statement: "During the first eight years of the study, persons developed coronary heart disease per 1000 persons who entered the study free of disease."

• Age-adjusted mortality rate
• Age-specific prevalence rate
• Incidence rate
• Prevalence rate
• Standardized mortality ratio - ANSWER-Incidence rate [Statement depicts new cases in an risk population, the definition of incidence.] Exam 1 Epidemiologic studies of the role of a suspected factor in a disease may be observational or experimental. The essential difference between experimental and observational studies is that in experimental studies... - ANSWER-Some process is used to assign the exposure/intervention to study subjects. [In experimental studies, some process is used to assign the factor being evaluated to each subject. Thus, the study subjects are intervened, whereas in observational studies they are just observed and there is no intervention (i.e.: exposure groups are naturally sorted).] Exam 1 The period of time between exposure to a causative agent and the appearance of the first clinical manifestations of the disease is called... - ANSWER-Incubation period [Section 4] Exam 1 External validity is... - ANSWER-Generalizability [Section 5] Exam 1 To the epidemiologist, each of the following is an advantage of utilizing death certificates... - ANSWER-- Available on a continuous basis over many years
• Convenient to use
• Provide a very high probability the person listed is truly deceased.
• Inexpensive to use EXCLUSION: Accuracy and detail of diagnoses listed as underlying causes of death

[The accuracy and detail (or lack thereof) of diagnoses listed as underlying causes of death is a disadvantage of relying on the cause of death data.] Exam 2 Most appropriate descriptive term? Febrile respiratory tract infections develop in approximately 80 percent of children infected with influenza.

• Communicability
• Immunogenicity
• Incidence
• Pathogenicity
• Virulence - ANSWER-Pathogenicity [Refers to the number of cases of disease divided by the number of people infected. In this case, 80% of the children infected developed the disease.] Exam 2 A survey revealed that of 225 families in which there had been a known case of poliomyelitis, 56 had a dog as a family pet. In another survey, 30 of 99 poliomyelitis patients had a dog. The inference that dogs are a risk factor for poliomyelitis is...
• Correct
• Incorrect because a proportionate ratio is used when a rate is required to support the inference
• Incorrect because of failure to distinguish between incidence and prevalence
• Incorrect because of failure to recognize a possible cohort phenomenon
• Incorrect because there is no control or comparison group - ANSWER-- Incorrect because there is no control or comparison group [Cross-sectional (survey) data is not a good study design for causal inference. There is no information on people who had dogs, but did not have poliomyelitis. Both groups of people discussed in the problem are groups of known cases of poliomyelitis and the number of those who had a dog as a pet. Although the survey data is on two groups, they are similar groups of patients. No comparison group of people who had dogs, but had no poliomyelitis is discussed. As this is cross-sectional data, we also do not have information on the temporality of the association (i.e. which came first the dog or poliomyelitis).] Exam 2 Effect modification - ANSWER-Occurs when the magnitude of the chosen measure of association between a causal agent and a disease differs according to the level of a third variable. Exam 2

In an observational analytic epidemiological study of a potential protective factor, the true risk ratio was 0.6, and the study had a bias away from the null hypothesis. The study risk ratio was most likely which of the following:

• 3.0 - ANSWER-0. [Since we are told there is a bias away from the null (i.e. a value of 1.0), then the study value must be beyond the true value (away from 1). Since the true value is 0.6, it cannot be higher than 0.6, which would bias it toward the null hypothesis. Therefore, the answer must be 0.3, which is the only value provided that is further away from 1 on the protective side.] Exam 2 Most appropriate descriptive term? Approximately 50 percent of household contacts of a child who has a common cold become infected.
• Communicability
• Immunogenicity
• Incidence
• Pathogenicity
• Virulence - ANSWER-- Communicability [Communicability refers to the ability of a pathogen to be transmitted from one host to another. The communicability of the common cold in this case is 50%. This means that 50% of the people with a cold will pass it along to someone else.] Exam 2 Usefulness of mortality data as an indicator of disease frequency is more accurate when the disease of interest... - ANSWER-- Has a high case fatality rate
• Is relatively easily diagnosed Exam 2 The causes of death on a death certificate can be certified by the... - ANSWER-Medical examiner or coroner Exam 2 Cystic fibrosis is an autosomal recessive genetic disorder that is caused when an individual has mutations in both copies of their CFTR gene (i.e. has two mutations). Carries of cystic fibrosis have a mutation in only one copy of their CFTR gene (i.e. have only one mutation). Common screening panels for cystic fibrosis may not detect all types of genetic mutations of the CFTR gene that can occur (i.e. individuals with CFTR mutations in one or both of their CFTR genes may not be detected).

A study comparing carries of cystic fibrosis is conducted where these two groups of patients are identified based on having only one mutation or two mutations detected by a common screening panel, respectively. What potential type of bias may occur here?

• Surveillance Bias
• Recall Bias
• Misclassification Bias
• Exclusion Bias - ANSWER-- Misclassification Bias [Misclassification bias may occur if some of the genetic mutations are missed by the screening panel. If only one mutation is detected in a subject who has cystic fibrosis ( mutations), that individual will be misclassified as a cystic fibrosis carrier and not actually having cystic fibrosis. In other words, some of the identified "carriers" may actually have a second mutation that is missed by the screening panel, and should be correctly classified as a case of cystic fibrosis] Exam 2 A study of mortality patterns in 20 countries found a positive correlation that was statistically significant (p-value < 0.001) between cigarettes sold per capita and mortality rates from cancer of the oral cavity. This finding could be explained by...
• Cigarette smoking being associated with cancer of the oral cavity
• Countries with high cigarette consumption rates having populations that are more susceptible to cancer of the oral cavity for reasons other than smoking
• Both
• Neither - ANSWER-- Both [The significance of the association does not explain how the association occurred. Both explanations are viable. There is no information to indicate otherwise (i.e. confounders that have been included in the analysis, etc.).] Exam 2 Investigators examining the association between daily aspirin use (75mg) and colon cancer risk report a relative risk of 0.89 (95% CI 0.75-1.12) comparing aspirin users to non-users. From the information presented we can say that:
• The authors found an 11% reduction in risk of colon cancer with daily aspirin use, that is unlikely due to chance alone.
• The effect estimate is statistically non-significant at the 5% level (alpha 0.05)
• Both
• Neither - ANSWER-The effect estimate is statistically non-significant at the 5% level (alpha 0.05) [Section 10. If the finding was statistically non-significant, then we cannot conclude that option A (11% reduction in risk) was correct.] Exam 2

Bias - ANSWER-A systematic error that is caused by how a study is designed, conducted or analyzed, which results in inaccurate estimates of the effect of exposure on disease. [Section 10] Exam 2 A study of all women age 20 to 25 years old in a large industrial state found that the annual rate of new cases of cervical cancer in women who used oral contraceptives was 7/100,000 and that it was 3/100,000 in those who did not use oral contraceptives. ON the basis of these data alone, the inference that taking oral contraceptives causes cervical cancer is....

• Correct
• Incorrect because a proportion is used when a rate is required to support the inference
• Incorrect because the two groups may differ in other relevant factors
• Incorrect due to failure to adjust for possible differences in age distributions of users and non-users.
• Incorrect due to failure to distinguish between incidence and prevalence - ANSWER-- Incorrect because the two groups may differ in other relevant factors [The study did not take into account any other possible factors that may influence oral contraceptive use and/or cervical cancer status, including confounders] Exam 2 A secondary household attack rate is most often used to... - ANSWER-Estimate degree of communicability of the disease. [Section 8. The secondary attack rate is the number of new cases of disease developing during a stated time period among those members of a closed group who are at risk. It indicates spread of disease within a group and is another type of incidence rate.] Exam 2 Is the threat of confounding a bigger problem in a descriptive epidemiologic study involving a measure of association, or in an analytic epidemiologic study involving a measure of association? -Bigger problem in an analytical study -Bigger problem in a descriptive epidemiologic study. -Both - ANSWER-Bigger problem in a descriptive epidemiologic study. [Although confounding can bias associations in many analytical epidemiological studies, the threat of confounding is typically greater in descriptive epidemiologic studies. This is because there is no control/comparison group.] Exam 2 You are interested in assessing the relationship between sample size, level of significance, and power. Sample size requirements are increased by...

• Changing the level of significance from 0.05 to 0.
• Changing the power from 80% to 90%
• Both
• Neither - ANSWER-- Both [Section 10. Part 1.] Exam 2 In a study of IUD (intrauterine device) use an risk of ectopic pregnancy, patients with ectopic pregnancy are identified from emergency room visits, and the patients without ectopic pregnancy were sampled from fertility clinic patients. The most likely type of bias resulting from this aspect of the study is... - ANSWER-Selection [The controls selected from a fertility program are not likely to be using birth control and the decision to select controls and cases so differently will lead to a pre-determined conclusion. This is because the design of the study is set up so the controls are already less likely than the cases to have the exposure. A measure of a true association will be difficult when the likelihood of exposure is already unbalanced.] Exam 2 When ranking study designs, which of these designs would generally provide the highest quality of evidence?
• Non-randomized trial with good control of confounding; well conducted in other respects
• Randomized controlled trial, but with deficiencies in execution or analysis
• Cohort study with hypothesis specified after analysis, good data, confounders accounted for
• Cohort study with hypothesis specified prior to analysis, good data, confounders accounted for
• Case-control study with hypothesis specified prior to analysis but with problems in the data or the analysis - ANSWER-- Non-randomized trial with good control of confounding; well-conducted in other respects [Section 11] Exam 2 In a case-control study evaluating the duration of computer use each day and repetitive strain injury (RSI), the patients with RSI tended to overestimate their frequency of computer use. In which direction could the study findings be biased?
• Bias towards the null
• Bias away from the null
• Results can be biased in either direction - ANSWER-- Results can be biased in either direction [Recall bias is a type of differential misclassification bias, and is a particular concern here because cases are self-reporting a higher duration of computer use than controls without RSI. If the controls do not also overestimate their duration of computer use, then

there will be a difference in how the groups are reporting their behavior (differential misclassification). This can lead to a bias either towards or away from the null, as the bias is likely differential between case groups.] Exam 2 To conclude that an observed association between an exposure and disease is internally valid, an investigator should evaluate or reject as alternative explanations for the research findings all of the following... - ANSWER-- Bias

• Chance
• Confounding
• Interaction (effect modificatin) EXCLUDES: Generalizability [Section 10. Generalizability refers to external validity, not internal validity.] Exam 2 In a study of 50 cases and 50 controls, it is determined that the difference found with respect to a possible etiologic factor is not statistically significant at the 5% level. One may conclude from this finding that...
• Chance or random error is not a possible explanation
• Confounding has been eliminated
• Observer or interviewer bias has been eliminated
• The lack of statistical significance is solely the result of sampling variation
• None of the above - ANSWER-- None of the above [Statistical significance refers to there being less than a 5% probability of observing a result as extreme as that observed due solely to chance. This means that the association is not likely to die to chance. If something is not statistically significant then chance could still be a viable explanation. Because of the limited information, one of the other options can really be concluded.] Exam 2 Most appropriate descriptive term? Death occurs in approximately 20 percent of cases of pneumococcal meningitis.
• Communicability
• Immunogenicity
• Incidence
• Pathogenicity
• Virulence - ANSWER-- Virulence [Virulence refers to the cases of severe and fatal disease divided by all cases of disease. In this case, one out of five cases of pneumococcal meningitis resulted in death, an indication of virulence.] Exam 2 In a case-control study of the relationship between smoking and myocardial infraction, controls (those without MI) are matched to cases (those with MI) on the basis of race,

sex and geographic location, is intended to decrease the chance of which of the following biases?

• Confounding bias
• Interviewer bias
• Non-response bias
• Recall bias
• Surveillance bias - ANSWER-Confounding bias [Section 10. Part 2. Matching is a method used to control for confounding. It is incorporated into the study at the design stage and taken into consideration during analysis.] Exam 2 The CDC provide guidelines when investigating suspected cancer clusters and responding to community concerns. In which stage of this four-step process would an excess incidence be calculated? - ANSWER-Step 2 [Section 9, slide 14. Assessment of an excess in incidence would be undertaken in Step 2.] Exam 2 Consider a disease with two alleles, A and a. The mating types that could produce a heterozygous child are
• Aa x aa
• AA x aa
• Aa x AA
• Aa x Aa
• All of the Above - ANSWER-All of the Above (Need a large A and small A to be heterozygous) Lecture 20 Clicker Quiz - Final Exam Consider a disease with two alleles, A and a. Which mating types give the highest proportion of heterozygous offspring?
• Aa x aa
• AA x aa
• Aa x AA
• Aa x Aa
• All of the above - ANSWER-AA x aa [Each parent will give one of their alleles to their offspring. In an AA x aa combination, the only type of allele parent one can give is A, and the only type of allele parent two can give is a. This means that every combination possible for the offspring will be Aa, a heterozygous pairing. All other choices will have at least one homozygous pairing, either AA or aa.] Lecture 20 Clicker Quiz - Final Exam

It is possible for a male to have received a sex chromosome from one of his four grandparents. For a male child, which grandparent could not have transmitted, via his parents, a sex chromosome?

• Maternal grandfather
• Maternal grandmother
• Paternal grandfather
• Paternal grandmother - ANSWER-- Paternal grandmother [A male has the sex chromosome pairing of XY, while a female has XX. Since we are talking about a male child, we are looking at how he inherits his XY pairing. The X will come from his mother, who could have received that X from either her mother or her father. Therefore, either his maternal grandfather or maternal grandmother may have contributed that X. The male offspring would have received his Y from his father. However, only males can pass the Y chromosome to offspring. Therefore, the Y the son received must have been passed on from his paternal grandfather. This means that the paternal grandmother could have contributed a sex chromosome.] Lecture 20 Clicker Quiz - Final Exam The risk of occurrence in first degree relatives of people with disease X is compared with first degree relatives of people without disease X. The type of study represented by this activity is best described as a (an)
• Adoption study
• Inbreeding study
• Migrant study]
• Recurrence risk
• Twin study - ANSWER-- Recurrence Risk Lecture 20 Clicker Quiz - Final Exam In general, screening should be undertaken for diseases with each of the following characteristics
• Diseases with high prevalence in identifiable subgroups of the population
• Diseases for which case-fatality rates are high
• Diseases with a natural history that can be altered by medical intervention
• Diseases that are difficult to diagnose
• Diseases for which treatment efficacy has been shown to be effective - ANSWER-- Diseases that are difficult to diagnose The same screening test is applied in a uniform manner in two populations. The prevalence of the disease being screened is 10% in population A and 1% in population B. Which of the following statements is true?
• Reliability is higher in population A than in population B.
• Sensitivity is higher in population A than in population B.
• Specificity is higher in population A than in population B.

• The percent of all positive screening tests that have true positive results is lower in population A than in population B.
• The percent of all positive screening tests that have false-positive results is lower in population A than in population B. - ANSWER-- The percent of all positive screening tests that have false-positive results is lower in population A than in population B. Plan A and Plan B for follow-up of newly detected hypertensives were tested in eastern and western areas of Community X, respectively. Results are shown in the table below. The difference in success rates was statistically significant (p<0.01). Health officials decided not to change to Plan B in the eastern area of Community X because of the magnitude of the difference. This implies that
• They attributed the difference in success rates to chance alone.
• They distinguished between statistical significance and practical importance of the difference in success rates.
• They feel the samples were too small to justify a decision to adopt Plan B.
• • ANSWER- Censoring in an intervention study whose end point is mortality (or death) occurs when
• Subjects are excluded from the study before it begins because of the presence of a particular factor or complication.
• Subjects die and the cause of death is unknown.
• Subjects die before the planned termination of the study.
• Subjects fail to comply with their assigned intervention.
• The study ends before all subjects have died. - ANSWER-- The study ends before all subjects have died. The prior use of aspirin is compared among 500 patients with newly diagnosed colon cancer and 1000 healthy persons. What type of study design is this? -Case-control study -Randomized Control Trial (RCT) -Cohort study -Correlational study -Cross sectional study - ANSWER-Case-control study P.S. 1 In a study of the relationship between reproductive abnormalities and in utero exposure to diethylstilbestrol (DES), the incidence rates of reproductive abnormalities in individuals whose mothers were exposed to DES when they were pregnant 20-30 years previously are compared to the incidence rates of reproductive abnormalities in individuals who were not exposed to DES 20-30 years previously. What type of observational analytic study is this? -Case-control study -Retrospective Cohort study -Prospective Cohort study

-Ecologic study - ANSWER-Retrospective cohort study P.S. 1 A study is performed that consists of comparing the incidence of gonorrhea and the death rate from cervical cancer in each of the following states: Alabama, California, Colorado, Illinois, Iowa, Louisiana, Massachusetts, Minnesota, New York, Oregon, South Carolina, and Tennessee. The resulting data points are plotted on a graph with the y-axis being the cervical cancer death rate and the x-axis the gonorrhea incidence rate. This type of study is best described as? -Case-control study -Ecologic -Cohort study -Randomized Controlled Trial (RCT) -Case Series - ANSWER-Ecologic P.S. 1 Two cities are classified according to the amount of natural fluoride in their drinking water supplies. The proportion of children with one or more dental caries is compared in the two cities. What type of observational analytic study is this? -Case-control study -Retrospective cohort study -Prospective cohort study -Ecologic study - ANSWER-Ecologic Study P.S. 1 The reported national incidence rates of hepatitis C infection are associated with corresponding national mortality rates for liver cancer. What type of study design is this? -Case-control study -Randomized Controlled Trial (RCT) -Cohort study -Correlational study -Cross-sectional study - ANSWER--Correlational Study P.S. 1 Lung cancer prevention is studied in a population of 12,000 smokers who are assigned randomly to receive either vitamin E pill or a placebo. What type of study design is this? -Case-control study -Randomized Controlled Trial (RCT) -Cohort study -Correlational study -Cross-sectional study - ANSWER-Randomized Controlled Trial (RCT)

P.S. 1

Describe the usual pattern of reasoning in epidemiology? (Match the ordered steps to their logical process of reasoning). - ANSWER-Step 1: Develop a hypothesis Step 2: Test the hypothesis by comparing an exposed human population and an appropriate control group Step 3: Systematically collect & analyze data Step 4: Assess the validity of any observed statistical associations Step 5: Judge whether the observed associations represent cause-effect relationships P.S. 1 During the past summer, a survey is conducted to determine the prevalence of aortic valvular stenosis and associated conditions within the general population of Iowa. What study design is this? -Case-control study -Randomized Controlled Trial (RCT) -Cohort study -Correlational study -Cross-sectional study - ANSWER-Cross sectional study P.S. 1 Inductees into the army are asked about their smoking history and current habits. Smokers and nonsmokers are subsequently compared in relation to the development of lung cancer and other chronic diseases. What type of observational analytic study is this? -Case-control study -Retrospective cohort study -Prospective cohort study -Ecologic study - ANSWER-Prospective cohort study P.S. 1 The smoking histories of patients entering a hospital with lung cancer are compared with the smoking histories of patients entering for other conditions requiring surgery. What type of observational analytic study is this? -Case-control study -Retrospective cohort study -Prospective cohort study -Ecologic study - ANSWER--Case-control study

P.S. 1

Observation A: The age-adjusted incidence rate for breast cancer in Japanese women is considerably lower than the age-adjusted incidence rate for breast cancer in North American women. The proportion of Japanese women who smoke cigarettes is also much lower than the proportion of North American women who smoke cigarettes. Observation B: Within North America, cigarette smoking does not increase the risk for breast cancer, and within Japan, smoking does not increase the risk for breast cancer. Which of the answers given below do you believe is correct?

• Observation A provides better evidence on whether or not a causal association between smoking and breast cancer exists than Observation B.
• Observation B provides better evidence on whether or not a causal association between smoking and breast cancer exists than Observation A.
• Observations A and B provide equally good evidence on whether or not a causal association - ANSWER-Observation B provides better evidence on whether or not a causal association between smoking and breast cancer exists than Observation A. P.S. 2 The association between cigarette smoking and lung cancer has been subjected to considerable scrutiny. Which of the following statements both strengthen the association between cigarette smoking and lung cancer and move the evidence toward the direction of a causal relationship?
• The risk of lung cancer increases as the daily consumption of cigarettes increases and/or as the duration of smoking increases.
• Ex-smokers have a lung cancer risk intermediate between those of nonsmokers and current smokers.
• Animal experiments have shown an increased risk for precancerous lesions following tobacco smoke inhalation.
• Prospective studies agree with retrospective cohort and case-control studies about the presence and direction of the association.
• All of the above - ANSWER-All of the Above P.S. 2 In a case-control study evaluating occupational exposure to aluminum and risk of Alzheimer's disease, relative to no exposure, the odds ratios are:low exposure = 1. (95% CI, 0.9 - 2.0);moderate exposure = 1.7 (95% CI, 1.4 - 2.3);high exposure = 2. (95% CI, 2.0 - 2.9). Using this information, what is the most likely criterion for causality? -Biologic plausibility -Consistency of results -Correct temporal sequence

-Presence of a dose-response relationship -Strength of association - ANSWER-Presence of a dose-response relationship P.S. 2 On January 14, 1960, a one-day census of mental hospitals was carried out in 12 Caribbean islands. The report of this census noted: When we examine the first admissions by length of stay, we find that 18 percent... have been hospitalized under one year, 19 percent between one and five years, and 63 percent for five years or longer. That is, the majority of first admissions are long-stay patients (Report on the Census of Mental Hospitals in the Caribbean, 1960). What type of study design was this? -Case-control study -Randomized Controlled Trial (RCT) -Retrospective cohort study -Prospective cohort study -Cross-sectional Study - ANSWER-Cross sectional study P.S. 2 On January 14, 1960, a one-day census of mental hospitals was carried out in 12 Caribbean islands. The report of this census noted: When we examine the first admissions by length of stay, we find that 18 percent... have been hospitalized under one year, 19 percent between one and five years, and 63 percent for five years or longer. That is, the majority of first admissions are long-stay patients (Report on the Census of Mental Hospitals in the Caribbean, 1960). What type of study would be necessary to answer questions about duration of stay in long-term hospitals? -Case-control study -Randomized Controlled Trial (RCT) -Cohort study -Cross-sectional Study - ANSWER-Cohort Study P.S. 2 Five published case-control studies evaluating the same exposure and disease produce the following odds ratios:1.4 (95% CI, 0.9 - 2.4)1.7 (95% CI, 1.3 - 2.5)2.4 (95% CI, 1.3 - 4.61.9 (95% CI, 1.5 - 2.7)2.0 (95% CI, 0.9 - 5.4) Using this information, what is the most likely criterion for causality? -Biologic plausibility -Consistency of results -Correct temporal sequence -Presence of a dose-response relationship -Strength of association - ANSWER-Consistency of results

P.S. 2

During the period 1930-1970, the annual number of deaths due to cancer in the United States increased from 118,000 to 331,000 (i.e.: an increase of 180.5%). One explanation for this steep increase in the number of cancer deaths could be an increased exposure of the population to carcinogenic substances. What are other possible explanations?

• The population of the U.S. increased during this time period from 117 million to 230 million inhabitants. The mortality rate from cancer (number of cancer deaths in one year/100,000 inhabitants) increased by 61.5% from 1930 to 1970.
• The age distribution of the population changed toward a greater proportion of older people. Age-standardized mortality from cancer increased by 9.5% from 1930 to 1970.
• Improved diagnostic procedures may have contributed toward more deaths from cancer being recorded, but improved therapy may have contributed to a decrease in mortality from cancer. - ANSWER-All of the Above (P.S. 3) Epidemiology is
• A Greek word meaning the doctrine of what is among or happening to people.
• The study of the distribution and determinants of health-related states or events in specified human populations and the application of this study to control of health problems.
• Both
• Neither - ANSWER-Both [Section 1, Slides 1&2, Lecture 02 Clicker Quiz - Exam 1] The father of epidemiology is: -Hippocrates -Edward Jenner -John Snow -Socrates -William Farr - ANSWER-John Snow Lecture 03 Clicker Quiz - Exam 1 This investigator took cowpox material from a lesion on the hand of a dairy maid and inoculated an 8 year old "volunteer". -Hippocrates -Edward Jenner -John Snow -Socrates -William Farr - ANSWER-Edward Jenner

Lecture 03 Clicker Quiz - Exam 1 From 1855 through the first half of the 20th century, the study of epidemiology is largely confined to: -Infectious disease -Chronic disease -Both -Neither - ANSWER-Infectious Disease Lecture 03 Clicker Quiz - Exam 1 Disease prevention is achieved through a

• Population-based (public health) approach
• High-risk (often requires a clinical action) approach
• Both
• Neither - ANSWER-Both Lecture 03 Clicker Quiz - Exam 1 An epidemiologic study begins with 1000 patients with newly diagnosed lung cancer and 500 healthy controls. Thereafter, the study investigators collect data on the prior use of cigarettes. Which of the following types of study design best fits this description?
• Case-control study
• Clinical trial
• Cohort study
• Correlational study
• Cross-sectional study - ANSWER-Case-control study Lecture 03 Clicker Quiz - Exam 1 1500 adults working for Boeing aircraft industry were initially examined in 1960 and were evaluated for coronary heart disease using diagnostic criteria as well as for their work exposures and lifestyle characteristics. Every five years since they have been evaluated in a similar manner. The study design is best described as a(an)
• Case-control study
• Cross-sectional study
• Intervention study
• Prospective cohort study
• Retrospective cohort study - ANSWER-Prospective Cohort Study Lecture 03 Clicker A random sample of middle-aged sedentary adults was selected from a community and each adult was examined for heart disease. All those having the disease were excluded from the study. All others were randomly assigned to either an exercise group, which

met regularly at local gyms, or to a control group. Both groups were evaluated at regular intervals for heart disease. The study design is best described as

• Case-control study
• Cross-sectional study
• Intervention study
• Prospective cohort study
• Retrospective cohort study - ANSWER-Intervention study Lecture 03 Clicker Quiz - Exam 1 The variation in severity of illness to a given exposure is called the
• Incubation or induction period
• Latent period
• Both
• Neither - ANSWER-Neither [Variation in severity of illness addresses the biologic spectrum and variation in host response, not the incubation, induction or latent period.] Lecture 04 Clicker Quiz - Exam 1 Descriptive Epidemiology is
• Primarily useful for hypothesis testing
• The study of the amount and distribution of disease within a population by person, place, and time
• Both
• Neither - ANSWER-The study of the amount and distribution of disease within a population by person, place, and time Lecture 04 Clicker Quiz - Exam 1 The sequence of studies in human populations typically begins with
• A case-control study
• A clinical trial
• A prospective cohort study
• Descriptive studies - ANSWER-Descriptive studies [Descriptive studies consist of clinical observations and available data.] Lecture 04 Clicker Quiz - Exam 1 In the United States, state incidence rates of hepatitis C infection are associated with corresponding state mortality rates for liver cancer. Which of the following types of study design best fits this description?
• A case-control study
• A clinical trial
• Cohort study

• Correlational study
• Cross-sectional study - ANSWER-Correlational Study [This question is looking at two population level data and associating the two rates. The only population level study listed is the correlational study. The other studies are all done at the individual level.] Lecture 04 Clicker Quiz - Exam 1 National per capita use of pesticides is associated with national non-Hodgkin lymphoma (NHL) mortality rates, but patients with NHL do not have higher pesticides levels than persons without NHL. This relationship is most consistent with
• Birth cohort effect
• Confounding bias
• Ecologic fallacy
• Recall bias
• Selection bias - ANSWER-Ecologic Fallacy Lecture 04 Clicker Quiz - Exam 1 Types of study designs used for descriptive epidemiology include each of the following except Aggregate study Case-control study Case report Case series Correlational study - ANSWER-Case Control Study Lecture 04 Clicker Quiz - Exam 1 To establish internal validity in an epidemiologic study, you do each of the following except -Assure generalizability -Describe interaction -Exclude bias (systematic error) as an explanation -Exclude chance (random error) as an explanation -Exclude confounding as an explanation - ANSWER-Assure generalizability Lecture 05 Clicker Quiz - Exam 1 In evaluating types of causal relations for a given factor, the following are true: -A factor is considered sufficient when without it the disease never develops. -A factor is considered necessary when in its presence the disease always develops. -Both -Neither - ANSWER-Neither Lecture 05 Clicker Quiz - Exam 1

Factors A, B, or C can each individually cause a certain disease without the other two factors, but only when followed by exposure to factor Z. Exposure to factor Z alone is not followed by the disease, but the disease never occurs in the absence of exposure to factor Z. Factor B is: -A necessary and sufficient cause -A necessary, but not sufficient, cause -A sufficient, but not necessary cause -Neither necessary nor sufficient - ANSWER-Neither necessary nor sufficient [It is important to remember that we are evaluating factor B, and not factor Z. With factor B present, disease will still not occur if factor Z is not present. This makes factor B not sufficient, as disease will not always occur in its presence. Without factor B, disease can still occur if either factor A or C is present. This makes factor B not necessary, as disease still occurs in its absence. If the question had asked about factor Z, factor Z would be considered a necessary, but not sufficient cause.] Lecture 05 Clicker Quiz - Exam 1 Each of the following is an important criterion when making causal inferences except -Absolute risk -Biologic plausibility -Consistency of association in several studies -Dose-response relationship -Strength of association - ANSWER-Absolute Risk Lecture 05 Clicker Quiz - Exam 1 In a case-control study evaluating occupational exposure to aluminum and risk of Alzheimer's disease, relative to no exposure, the odds ratios (i.e., measures of association) are: For low exposure = 1.3; For moderate exposure = 1.7; For high exposure = 2.3.These data best fit which of the following guidelines for causality? -Biological plausibility -Consistency of results -Correct temporal sequence -Dose-response relationship -Strength of association - ANSWER-Dose-Response relationship [There is a clear correlation between the amount of exposure and odds ratio. As the amount of exposure increases, so does the odds ratio.] Lecture 05 Clicker Quiz - Exam 1 There is epidemiologic literature showing a positive association between aluminum exposure and Alzheimer's disease. At post-mortem examination, the pathologic lesions within brains of patients with Alzheimer's disease are shown to contain unusually high levels of aluminum. These data best fit which of the following guidelines for causality?

-Biological plausibility -Consistency of results -Correct temporal sequence -Dose-response relationship -Strength of association - ANSWER-Biological plausibility [The focus of this question is on the pathologic lesions. This is a biologic piece of evidence to support epidemiologic literature on a positive association between aluminum exposure and Alzheimer's disease. The lesions allow for biologic plausibility. Without the lesions, there would be no biologic support. The lesions themselves were not found in the original epidemiological studies looked at aluminum exposures studies, not pathologic findings.] Lecture 05 Clicker Quiz - Exam 1 For a disease such as liver cancer, which is highly fatal and of short duration: -Incidence rates and mortality rates will be similar. -Incidence rates will be much higher than mortality rates. -Incidence rates will be unrelated to mortality rates. -Mortality rates will be much higher than incidence rates. -None of the above - ANSWER-Incidence rates and mortality rates will be similar. Lecture 06 Clicker Quiz - Exam 1 Summerville is a community of 100,000 persons. During 2010, there were 1,000 deaths from all causes. All new cases of tuberculosis have been accounted for, and they total 300 (200 males and 100 females). During 2010, there were 60 deaths from tuberculosis, 50 of them in males. If the incidence rate remains constant, what is the likely effect on the prevalence rate as case fatality from tuberculosis decreases? -Decreases -Increases -Stay the same -Cannot be determined from the information provided - ANSWER-Increases Lecture 06 Clicker Quiz - Exam 1 Communities P and Q have equal age-adjusted all-cause mortality rates using direct standardization. Community P has a lower crude all-cause mortality rate than Community Q. One may conclude that -The two communities have identical age distributions -Diagnosis is more accurate in P than Q -P has an older population than Q -Diagnosis is less accurate in Q than P -P has a younger population than Q - ANSWER-P has a younger population than Q

[When rates are adjusted, it means that they have been standardized to allow for comparison. The fact that the age-adjusted rates are equal between these two communities just tells you that population distribution differences aside, there are equal rates of death among age-specific categories. Since the crude rates are not the same, the rate with the larger crude rate has the older population and the community with the smaller crude rate has the younger community.] Lecture 07 Clicker Quiz - Exam 1 A series of 1,000 female patients with breast cancer included 32 who were pregnant. From this, one may conclude -Breast cancer is a rare complication of pregnancy. -If age adjustments are made we can determine the risk of breast cancer during pregnancy. -In this series, 3.2% of the breast cancer patients were pregnant. -In women of childbearing age, pregnancy increases the probability of breast cancer. -Pregnancy is a rare complication of breast cancer. - ANSWER-In this series, 3.2% of the breast cancer patients were pregnant. [Adjustments are used to compare rates, and there is only one group mentioned here. There is no comparison to be done based on the little information we are given. However, there is one option choice that is undeniably true. If we were to convert the information in the question to a rate, it would 32/1000 pregnant cancer patients. If you change that to a percent, what do you get 3.2%.] Lecture 07 Clicker Quiz - Exam 1 The observed cases in the study population are used in -Direct standardization to calculate category-specific rates -Indirect standardization to calculate the expected number of cases -Both -Neither - ANSWER-Direct standardization to calculate category-specific rates [The category-specific rates for the study population are used in direct standardization and are applied to the population distribution of a standard population. These rates would use observed cases from the study population in each category.] Lecture 08 Clicker Quiz - Exam 1 When applying indirect standardization, you need the following to calculate the expected number of cases -Category-specific rates in the study population -Category-specific distribution of the study population -Both -Neither - ANSWER-Category-specific distribution of the study population [The expected number of cases uses category-specific rates from a standard population applied to the distribution of the study population.] Lecture 08 Clicker Quiz - Exam 1

The following vaccine trial was performed: 1,000 randomly selected children 2 years of age were given a vaccine against a certain disease and followed for 10 years. Of these, 80% were never afflicted with the disease. Which of the following is the most correct conclusion regarding the vaccine? -The vaccine is excellent because of the high rate of immunization. -The vaccine is not very effective because it should have produced a higher immunization rate. -No conclusion is possible because no follow-up was made of non-vaccinated children. -No conclusion is possible because no test of statistical significance was performed. -The significant figure is 100% - 80% = 20%, the rate of acquiring the disease. - ANSWER-No conclusion is possible because no follow-up was made of non-vaccinated children. [We do not know how the disease would have progressed without the vaccine. It is possible that 80% (or more) of children who were not vaccinated also were never afflicted with the disease. Without knowing the difference between the vaccinated children and the non-vaccinated children no real conclusion can be made.] Lecture 08 Clicker Quiz - Exam 1 Each of the following statements about the routine autopsy is true except -Its performance typically affects the timing of the funeral. -Its performance typically allows the opportunity to have an open casket at the funeral home. -Notes and photographs may be taken to document any important findings. -Small pieces of tissue may be collected for examination under a microscope. -The body may be x-rayed or scanned to look for problems like fractures, tumors, or gunshot wounds - ANSWER-Its performance typically affects the timing of the funeral. [Autopsies are done generally very soon after death, while a funeral takes several days to plan. Autopsies typically do not impact the ability to have an open casket. The incisions done during an autopsy are made in areas that are easily concealed] Lecture 08 Clicker Quiz - Exam 1 An autopsy requires consent of the family or legal guardian when performed -For legal reasons -For medical reasons -Both -Neither - ANSWER-For medical reasons [Family permission for legal reasons (ie. in the case of homicide or suicide) is not needed. The medical examiner can decided whether a autopsy should be done or not without family permission.] Lecture 08 Clicker Quiz - Exam 1 A medical examiner is a