PHC 6001: Final Exam

A case-control study was conducted to help assess the potential relationship between vasectomy and prostate cancer. Data were: Vasectomy(+) & Cancer(+) = A = 61 Vasectomy(+) & Cancer(-) = B = 93 Vasectomy(-) & Cancer(+) = C = 114 Vasectomy(-) & Cancer(-) = D = 165 a+b = 154 c+d = 279 a+c = 175 b+d = 258 a+b+c+d = 433 The prevalence of vasectomy in the total population was _____ percent. The prevalence of vasectomy among cases (cancer + individuals) was _____ percent. The prevalence of vasectomy among controls (cancer - individuals) was _____ percent. The odds of having had a vasectomy among cases were _____. The odds of having had a vasectomy among controls were _____. The Odds Ratio of _____, a lower bound of the 95% CI of _____ and an upper bound of the 95% CI of _____ (calculate the 95% CI as shown in this link https://www.ncbi.nlm.nih.gov/books/NBK431098/) indicate that the odds of having had a vasectomy among cases were _____ (response options: greater than, lower than, the same as) the odds of having had a vasectomy among controls.

(154/433)*100 = 35.56; (61/175)*100 = 34.85; (93/258)*100 = 36.04; (61/175)/(114/175) = 0.53; (93/258)/(165/258) = 0.56; (61*165)/(93*114) = 0.94; ln(0.94) - 1.96 sqrt(1/61+1/93+1/114+1/165) = 0.63; ln(0.94) + 1.96 sqrt(1/61+1/93+1/114+1/165) = 1.41; the same as

In this study, 9,400 patients aged 60 and over were selected and followed. To be eligible, patients had to have been admitted with a diagnosis of hip fracture to one of 20 study hospitals. The patients' medical charts were reviewed by research nurses to obtain information about whether they developed a bedsore during hospitalization and whether they died while they were hospitalized. Results of the study are shown in the table below. Bedsore (+) & Died = A = 79 Bedsore (+) & Did Not Die = B = 745 Bedsore (-) & Died = C = 286 Bedsore (-) & Did Not Die = D = 8290 A+B = 824 C+D = 8576 A+C = 365 B+D = 9035 A+B+C+D = 9400 The risk of death among those with bedsore was ______ percent. The risk of death among those without bedsore was _____ percent. The risk of death was _____ time as high in people with bedsores as in people without bedsores. The investigators suspected that people who have lots of medical problems aside from their hip fracture are more likely to get bedsores and are also more likely to die. If that were the case, the severity of medical problems would be a confounding variable. As a part of the design of the study, the epidemiologists who did this study obtained information about the patients' other medical problems. The information was summarized into a score based on information about the patients' diseases when they were admitted to hospital. To create two groups, the researchers classified everyone who had a score of 5 or more into the high medical severity group and everyone whose score was less than 5 into the low medical severity group. Using the data from their study, they were able to establish the following facts: • Of the 79 people who had bedsores and died, 55 had high medical severity and 24 had low medical severity. • Of the 745 people who had bedsores and did not die, 51 had high medical severity and 694 had low medical severity. • Of the 286 people who had no bedsores and died, 5 had high medical severity and 281 had low medical severity. • Of the 8,290 people who had no bedsores and did not die, 5 had high medical severity and 8,285 had low medical severity. After organizing this information in 2X2 tables it was possible to determine that: The proportion of people with bedsores among those with high medical severity was _____ percent. The proportion of people with bedsores among those with low medical severity was _____ percent. The proportion of high medical severity group who died was _____ perecent. The proportion of low medical severity group who died was _____ percent. Based on this information, it was possible to conclude that: 1. Medical severity _____ (response options: was vs. was not) associated with having bedsores, because the proportion of individuals with bedsores among those who had high medical severity was _____ (response options: lower, the same, or higher) than the proportion of individuals with bedsores among those who had low medical severity. 2. Medical severity _____ (response options: was vs. was not) associated with mortality, because the risk of dying among those who had high medical severity was _____ (response options: lower, the same, or higher) than the risk of dying among those who had low medical severity. 3. Based on the last two statements, and if medical severity is not an intermediate step in the causal pathway between bedsores and mortality, we can conclude that medical severity _____ (response options: was vs. was not) a potential confounder. To determine whether medical severity is an actual confounder the researchers estimated the association between bed-sores and death separately in people with high and low medical severity. Based on the assessment of those associations it was possible to establish that: The relative risk of death comparing those with and without bedsores among those with high medical severity was _____. The relative risk of death comparing those with and without bedsores among those with low medical severity was _____. When comparing the crude or overall relative risk with the stratum-specific relative risk it was possible to determine that medical severity _____ (response options: was vs. was not) an actual confounder.

(79/824)*100 = 9.6; (286/8576)*100 = 3.3; 9.6/3.3 = 2.9; [(55+51)/(55+51+5+5)]*100 = (106/116)*100 = 91.4; [(24+694)/(24+694+281+8285)]*100 = (718/9284)*100 = 7.7; [(55+5)/(55+51+5+5)]*100 = (60/116)*100 = 51.7; [(24+281)/(24+694+281+8285)]*100 = (305/9284)*100 = 3.3; was; higher; was; higher; was; [(a1*d1/a1+b1+c1+d1)+(a2*d2/a2+b2+c2+d2)]/[(b1*c1/a1+b1+c1+d1)+(b2*c2/a2+b2+c2+d2)] = [(55*5/116)+(24*8285/9284)]/[(51*5/116)+(694*281/9284)] = 1.0; 1.0; was

The association between cellular telephone use and the risk of brain cancer was investigated in a case-control study. The study included 475 cases and 400 controls and the following results were seen: Cell phone user (+) & case = A = 270 Cell phone user (+) & control = B = 200 Cell phone user (-) & case = C = 205 Cell phone user (-) & control = D = 200 Cases = 475 Controls = 400 Calculate the odds ratio based on these data, to the nearest 0.1. OR = _____ Gender was considered a potential confounder and effect measure modifier in this study. The data were stratified into males and females in order to assess these issues. MALES Cell phone user (+) & case = A = 242 Cell phone user (+) & control = B = 150 Cell phone user (-) & case = C = 100 Cell phone user (-) & control = D = 50 FEMALES Cell phone user (+) & case = A = 28 Cell phone user (+) & control = B = 50 Cell phone user (-) & case = C = 105 Cell phone user (-) & control = D = 150 Stratum-specific OR for males = 0.8 Stratum-specific OR for females = 0.8 Is gender a confounder in this study? Yes or No? _____

(ad/bc) = (270*200)/(200*205) = 1.3; yes

Please complete the followng questions based on the abstract, tables, figures, and options provided: Abstract Background: Obesity is a major risk factor for venous thromboembolism (VTE), but it is unknown to what extent weight change over time affects VTE risk. Aims: To investigate the association between weight change and risk of incident VTE in a population-based cohort with repeated measurements. Methods: Participant data were collected from the Tromso 3 (1986-87), 4 (1994-95), 5 (2000-01) and 6 (2007-08) surveys. Subjects who attended two subsequent or more surveys were included (n=17802), and weight change between the surveys was calculated. Person-time at risk was accrued from the second of two subsequent visits until the next survey, the date of an incident VTE, migration, death or study end (December 31st 2012), whichever came first. Cox regression models were used to calculate risk of VTE according to change in body weight. Results: There were 302 incident VTE events during a median of 6.0 years of follow-up. Subjects who gained most weight (7.5-40.0 kg weight gain) had a 1.9-fold higher risk of VTE compared to those with no or a moderate (0-7.4 kg) weight gain (HR 1.92; 95% CI 1.38-2.68). The VTE risk by >=7.5 kgs over no or moderate (0-7.4 kg) weight gain was highest (HR 3.75; 95% 1.83-7.68) in subjects with baseline body mass index (BMI) >=30 kg/m2. There was a joint effect of weight gain and baseline BMI on VTE risk. Those with BMI >=30 who gained >=7.5 kgs had a 6.6-fold increase risk (HR 6.64; 95% CI 3.61-12.22) compared to subjects with BMI <25 and no or moderate (0-7.4 kg) weight gain. Conclusions: Our findings imply that further weight gain is a considerable risk factor for VTE, particularly in obese individuals. 1. According to the abstract, the "exposure" variable was _____ and the "outcome" variable was _____. 2. Since person-time estimates were calculated for exposed and unexposed groups, it is possible to estimate the _____ to assess the association between the exposure and the outcome (response options: cumulative incidence OR incidence rate). 3. Assuming the study started in 2006, this study would be considered a/an _____ (response options: retrospective, prospective, or ambidirectional) cohort study.

1. weight change; VTE 2. Incidence rate 3. Ambidirectional

To study the relationship between oral contraceptive (OC) use and ovarian cancer, CDC initiated a case-control study - the Cancer and Steroid Hormone (CASH) Study in 1980. Case-patients were enrolled through eight regional cancer registries participating in the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. The primary purpose of the CASH study was to measure and test the association between OC use and three types of reproductive cancer) breast cancer, endometrial cancer, and ovarian cancer. Enrollment of subjects into the study began in December 1980. During the first 10 months of the study, 179 women with ovarian cancer were enrolled. During the same period, 1,642 women were enrolled to serve as controls. Among the 1,052 women who reported ever having used contraceptives, 93 had a diagnosis of ovarian cancer. a. Create a 2x2 table depicting your study results. Oral Contraceptive (+) & Ovarian Cancer (+) = A = _____ Oral Contraceptive (+) & Ovarian Cancer (-) = B = _____ Oral Contraceptive (-) & Ovarian Cancer (+) = C = _____ Oral Contraceptive (-) & Ovarian Cancer (-) = D = _____ The odds of OC exposure among cases is calculated by diving 93 by _____. The odds of OC exposure among controls is calculated by diving _____ by 683. The odds ratio of _____ indicates that the odds of a case having used OCs was about _____ percent _____ (response options: less vs. more) than the odds of OC use among controls. In the analysis of use of oral contraceptives and ovarian cancer, age was related both to OC use and to case-control status. (OC users were younger than never-users; case-patients were younger than controls.) Therefore, the investigators decided to stratify the data by age and calculate stratum-specific and, if appropriate, summary statistics of the stratified data. Results are presented in table 2. Table 2. Ever-use of oral contraceptives and risk of ovarian cancer, stratified by age, Cancer and Steroid Hormone Study, 1980-1981 Ages 20-39 years A = 46 B = 285 C = 12 D = 51 Ages 40-49 years A = 30 B = 463 C = 30 D = 301 Ages 50-54 years A = 17 B = 211 C = 44 D = 331 The OR for women 20 to 39 years old was _____. The OR for women 40 to 49 years old was _____. The OR for women 50 to 54 years old was _____. Based on the analyses, age _____ (response options: does vs. does not) appear to meaningfully modify the relationship between oral contraceptives and ovarian cancer. The investigators observed that pregnancy was described as apparently protective against ovarian cancer. The investigators were interested in seeing whether the association between OC use and ovarian cancer differed for women of different parity. Table 3 shows parity-specific data. Parity 0 = Ever user = 20 patients; 67 controls; 0.3 (0.1-0.8) Age-adjusted odds ratios Parity 0 = Never user = 25 patients; 80 controls; 0.3 (0.1-0.8) Age-adjusted odds ratios Parity 1-2 = Ever user = 42 patients; 369 controls; 0.8 (0.4-1.5) Age-adjusted odds ratios Parity 1-2 = Never user = 26 patients; 199 controls; 0.8 (0.4-1.5) Age-adjusted odds ratios Parity >= 3 = Ever user = 30 patients; 520 controls; 0.7 (0.4-1.2) Age-adjusted odds ratios Parity >= 3 = Never user = 35 patients; 400 controls; 0.7 (0.4-1.2) Age-adjusted odds ratios Based on the analyses described in Table 3, parity _____ (response options: does vs. does not) appear to meaningfully modify the relationship between oral contraceptives and ovarian cancer.

A = 93; B = 959 C = 86; D = 683; 86; 959; (93*683)/(959*86) = 0.77; 1-0.77 = 23; less; (46*51)/(285*12) = 0.69; (30*301)/(463*30) = 0.65; (17*331)/(211*44) = 0.61; does not; does

What study type is most appropriate for the following scenario: When little is known about a rare disease

Case Control

What study type is most appropriate for the following scenario: When little is known about a rare exposure

Cohort

What study type is most appropriate for the following scenario: When you only have population level data

Ecological Study

T/F: A journal article critique should only include a discussion of what the authors did wrong in the study, not the positive aspects of the study.

False

T/F: If a study question can be answered using a randomized trial design, then that design should always be selected over observational designs.

False

T/F: If you are asked to review an article for a journal, then you should correct all spelling and grammar mistakes as well as critiquing the study itself.

False

True or False? A modifier does tell us whether an association is significant or not

False

True or False? Evidence for effect measure modification is present when the stratum-specific measures of association are approximately the same.

False

True or False? Findings on effect measure modification are not useful in explaining biological mechanisms of how an exposure leads to a disease outcome.

False

You are leading a research team to study the association between infection with Human Papillomavirus (HPV) and the development of oral cancer in Florida. For your Human Papillomavirus (HPV) and oral cancer study case control study, you enroll 263 cases and 981 controls. There are 58 of your cases who test positive for HPV and there are 146 of your controls who test positive for HPV. Calculate the Odds Ratio for this association rounding up to the nearest one-tenth.

Odds Ratio = (a/b)/(c/d) or ad/bc a = 58 b = 205 c = 146 d = 835 (58*835)/(205*146) = 1.6

What study type is most appropriate for the following scenario: When you are testing a new drug

Randomized Trial

T/F: An odds ratio that is equal to 1.0 indicates that there is no association between the risk factor and the outcome.

True

T/F: The Odds ratio (OR) can range from "0" to infinity.

True

T/F: The ideal comparison group in a cohort study would, if possible, consist of exactly the same individuals in the exposed group had they not been exposed.

True

True or False? Stratification is a useful method to examine whether there is effect measure modification of a variable on an association.

True

True or False? The term effect measure modification emphasizes that the effect of exposure on the health outcome is modified depending on the value of one or more control variables.

True

Answer the following questions based on the information presented in the tables: Table 1 n (56.6-0.1 kg loss) = 8547 n (0-7.4 kg gain) = 14331 n (7.5-40.0 kg gain) = 4501 Men, % (56.6-0.1 kg loss) = 48.3 (4124) Men, % (0-7.4 kg gain) = 45.9 (6581) Men, % (7.5-40.0 kg gain) = 43.5 (1958) Age, years (56.6-0.1 kg loss) = 59.0 +- 14.3 Age, years (0-7.4 kg gain) = 52.9 +- 13.3 Age, years (7.5-40.0 kg gain) = 47.1 +- 12.5 BMI, kg/m2 (56.6-0.1 kg loss) = 24.7 +- 3.9 BMI, kg/m2 (0-7.4 kg gain) = 25.7 +- 3.6 BMI, kg/m2 (7.5-40.0 kg gain) = 28.6 +- 4.3 Body weight, kg (56.6-0.1 kg loss) = 70.2 +- 13.2 Body weight, kg (0-7.4 kg gain) = 73.8 +- 12.8 Body weight, kg (7.5-40.0 kg gain) = 83.3 +- 14.1 Smoking, % (56.6-0.1 kg loss) = 36.1 (3087) Smoking, % (0-7.4 kg gain) = 31.6 (4530) Smoking, % (7.5-40.0 kg gain) = 28.4 (1280) Systolic blood pressure, mm Hg (56.6-0.1 kg loss) = 139 +- 23 Systolic blood pressure, mm Hg (0-7.4 kg gain) = 136 +- 20 Systolic blood pressure, mm Hg (7.5-40.0 kg gain) = 136 +- 19 Total cholesterol, mmol/L (56.6-0.1 kg loss) = 6.0 +- 1.2 Total cholesterol, mmol/L (0-7.4 kg gain) = 6.1 +- 1.2 Total cholesterol, mmol/L (7.5-40.0 kg gain) = 6.2 +- 1.2 HDL cholesterol, mmol/L (56.6-0.1 kg loss) = 1.6 +- 0.4 HDL cholesterol, mmol/L (0-7.4 kg gain) = 1.5 +- 0.4 HDL cholesterol, mmol/L (7.5-40.0 kg gain) = 1.4 +- 0.4 Triglycerides, mmol/L (56.6-0.1 kg loss) = 1.4 +- 0.8 Triglycerides, mmol/L (0-7.4 kg gain) = 1.5 +- 1.0 Triglycerides, mmol/L (7.5-40.0 kg gain) = 1.8 +- 1.2 Diabetes mellitus, % (56.6-0.1 kg loss) = 5.5 (468) Diabetes mellitus, % (0-7.4 kg gain) = 1.7 (238) Diabetes mellitus, % (7.5-40.0 kg gain) = 1.8 (81) Table 2 All subjects 56.6-0.1 kg loss = 49050 person-years of follow-up; 120 events; 2.45 (2.05-2.93) IR*(95% CI); 1.06 (0.83-1.37) HR(95% CI) Model 1; 1.15 (0.89-1.49) HR(95% CI) Model 2 0-7.4 kg gain = 87767 person-years of follow-up; 132 events; 1.50 (1.27-1.78) IR*(95% CI); Ref HR(95% CI) Model 1; Ref HR(95% CI) Model 2 7.5-40.0 kg gain = 28022 person-years of follow-up; 50 events; 1.78 (1.35-2.35) IR*(95% C); 1.93 (1.38-2.68) HR(95% CI) Model 1; 1.63 (1.15-2.30) HR(95% CI) Model 2 BMI <25 23.9-0.1 kg loss = 24846 person-years of follow-up; 30 events; 1.21 (0.84-1.73) IR*(95% CI); 0.74 (0.47-1.17) HR(95% CI) Model 1; 0.78 (0.47-1.29) HR(95% CI) Model 2 0-7.4 kg gain = 54616 person-years of follow-up; 53 events; 0.97 (0.74-1.27) IR*(95% CI); Ref HR(95% CI) Model 1; Ref HR(95% CI) Model 2 7.5-39.0 kg gain = 16815 person-years of follow-up; 19 events; 1.13 (0.72-1.77) IR*(95% CI); 1.86 (1.09-3.16) HR(95% CI) Model 1; 1.74 (0.96-3.18) HR(95% CI) Model 2 BMI 25-29.9 31.6-0.1 kg loss = 18028 person-years of follow-up; 65 events; 3.61 (0.28-4.60) IR*(95% CI); 1.24 (0.87-1.76) HR(95% CI) Model 1; 1.43 (0.95-2.13) HR(95% CI) Model 2 0-7.4 kg gain = 27556 person-years of follow-up; 63 events; 2.29 (1.79-2.93) IR*(95% CI); Ref HR(95% CI) Model 1; Ref HR(95% CI) Model 2 7.5-40.0 kg gain = 8639 person-years of follow-up; 15 events; 1.74 (1.05-2.88) IR*(95% CI); 1.21 (0.69-2.15) HR(95% CI) Model 1; 1.00 (0.53-1.89) HR(95% CI) Model 2 BMI >= 30 56.6-0.1 kg loss = 6176 person-years of follow-up; 25 events; 4.05 (2.74-5.99) IR*(95% CI); 1.24 (0.66-2.33) HR(95% CI) Model 1; 1.01 (0.51-2.00) HR(95% CI) Model 2 0-7.4 kg gain = 5584 person-years of follow-up; 16 events; 2.87 (1.76-4.68) IR*(95% CI); Ref HR(95% CI) Model 1; Ref HR(95% CI) Model 2 7.5-33.0 kg gain = 2567 person-years of follow-up; 16 events; 6.23 (3.82-10.17) IR*(95% CI); 3.75 (1.83-7.68) HR(95% CI) Model 1; 4.70 (2.17-10.18) HR(95% CI) Model 2 a. In total, _____ cases of VTE occurred over the follow-up period, of which the majority (n=_____), of VTE cases, occurred among those in the group who experienced a weight change of _____ (response options: 56.6-0.1 kg loss, 0-7.4 kg gain, 7.5-40.0 kg gain). b. Because there were (n=_____) individuals in the "7.5-40.0 kg" gain group and (n=_____) in the "56.6-0.1 kg loss" group, the number of person-years each of these two groups contributed was higher among the _____ (response options: 56.6-0.1 kg loss, 0-7.4 kg gain, 7.5-40.0 kg gain) group. c. The incidence of Venous Thromboembolism (VTE) in the total study population is _____ per 1,000 person years of follow-up. To calculate this estimate we divided the new cases in the numerator by the denominator, which is equivalent to _____ person years. (please include in your response only one decimal place). d. Based on incidence rates, compared with those individuals in the group "7.5-40.0 kg gain" (reference group), those in the group "56.6-0.1 kg loss", had _____ times the risk of developing VTE. e. Another exposure the researchers explored in this study was _____.

a. (120+132+50)=302; 132; 0-7.4 kg gain b. 4501; 8547; 56.6-0.1 kg loss c. [(8547+14331+4501=27379)/(49050+87767+28022=164839)]=1.8; 164839 d. (2.45/1.78)=1.4 e. BMI

Suppose that a case-control study was conducted among men aged 40-70 years in order to determine whether regular e-cigarette use increases the liklihood of heart attack. The case group was comprised of 1,000 men who had recently had a heart attack. Among the cases, 379 reported regular e-cigarette use prior to their heart attack. The control group was comprised of 1,000 individuals who never had a heart attack. Among the controls, 236 reported regular e-cigarette use. Is there an association between heart attack and regular e-cigarette use? Round your answer to the nearest decimal place. a. Create a 2x2 table depicting your study results. Regular e-cigarette use (+) & Heart attack (+) = A = _____ Regular e-cigarette use (+) & Heart attack (-) = B = _____ Regular e-cigarette use (-) & Heart attack (+) = C = _____ Regular e-cigarette use (-) & Heart attack (-) = D = _____ b. The prevalence of regular e-cigarette use in the total population was _____ percent. The prevalence of regular e-cigarette use among cases was _____ percent. The prevalence of regular e-cigarette use among controls was _____ percent. The odds that a case was a regular e-cigarette user were _____. The odds that a control was a regular e-cigarette user were _____. The odds of being a case among regular e-cigarette users were _____. The odds of being a case among non regular e-cigarette users were ______. Analyses of the association under study indicate that individuals who used e-cigarettes regularly were _____ times as likely to experience a heart attack than those who did not use e-cigarettes regularly.

a. 379; 236; 621; 764 b. [(a+b)/(a+b+c+d)]*100 = [(379+236)/(379+236+621+764)]*100 = (615/2,000)*100 = 0.3075*100 = 30.8; [a/(a+c)]*100 = [379/(379+621)]*100 = 0.379*100 = 37.9; [b/(b+d)]*100 = [236/(236+764)]*100 = 0.236*100 = 23.6; 379/621 = 0.6; 236/764 = 0.3; [(a+c)/(a+b)] = [(379+621)/(379+236)] = 1000/615 = 1.6; [(a+c)/(c+d)] = [(379+621)/(621+764)] = 1000/1385 = 0.8; (a/b)/(c/d) = (379/236)/(621/764) = 1.9

Consequences of non-compliance with the Common Rule can include: a. FWA suspension b. Fines c. Flogging d. All of the above

a. FWA suspension

In an experimental study, I'm selecting controls by assigning people admitted to the hospital on Monday, Wednesday, and Friday to treatment group A, and those admitted on Tuesday, Thursday, and Saturday to treatment group B. This selection of study subjects is: a. Non-randomized b. Randomized c. Not easy to manipulate d. One that eliminates selection bias

a. Non-randomized

One concern with case-control studies is that cases might remember their exposures better than controls, a phenomenon known as? a. Recall bias b. Case bias c. Hospital bias d. Control bias

a. Recall bias

A current study that examines lead exposure and prenatal outcomes in a group of women from 1960 to 1980 would be considered what type of cohort study? a. Retrospective cohort study b. Prospective cohort study c. Ambidirectional cohort study d. Concurrent cohort study

a. Retrospective cohort study

Which of the following statements is correct about IRB review of research proposals and research projects? a. The IRB must ensure that information given to subjects is in compliance with informed consent requirements b. The IRB does not need to notify researchers in writing of approval or disapproval of the research proposal c. The IRB must conduct continuing review of approved research at least 2 times per year d. The IRB does not require documentation of informed consent

a. The IRB must ensure that information given to subjects is in compliance with informed consent requirements

Which of the following statements about experimental studies is not correct? a. The exposure or treatment is not controlled by the investigator b. The person doing the research controls the exposure c. Study participants are usually randomly assigned to comparison groups d. A treatment and its side effects are evaluated

a. The exposure or treatment is not controlled by the investigator

Non-differential misclassification tends to bias study results in which direction? a. Towards the null b. Away from the null c. Either towards or away from the null

a. Towards the null

Answer "yes" or "no" to state whether a cohort study is best suited for each of the following scenarios: a. When little is known about a rare exposure: b. When little is known about a rare disease: c. When the study population will be difficult to follow: d. When you want to learn about multiple effects of an exposure:

a. Yes b. No c. No d. Yes

An experimental study was conducted among adults with Type 2 diabetes in order to determine if a new medication was more effective in reducing blood glucose levels than the currently used medication. What type of experimental study is this? a. Individual preventive b. Individual therapeutic c. Community preventive d. Community therapeutic

b. Individual therapeutic

The Health Professionals Cohort Study began in 2005 in order to evaluate a series of hypotheses about men's health relating nutritional factors to the incidence of serious illnesses such as cancer, heart disease, and other vascular diseases. Every two years, members of the study will receive surveys with questions about diseases and health-related topics like smoking, physical activity, and medications taken. The surveys that ask detailed dietary information will be administered in four-year intervals. What kind of cohort study is this? a. Ambidirectional b. Prospective c. Experimental d. Retrospective

b. Prospective

You are leading a research team to study the association between infection with Human Papillomavirus (HPV) and the development of oral cancer in Florida. You opt to carry out a case-control study. For your Human Papillomavirus (HPV) and oral cancer study, you are able to recruit cases for your study from the Florida Cancer Registry. All of the following are ways that you can recruit controls, except: a. Door-to-door recruitment b. Randomization of cases c. Random digit dialing d. Selection of hospital patients

b. Randomization of cases

Which of the following is a method for controlling confounding in the analysis phase only of a study? a. Randomiztion b. Stratification c. Matching d. Restriction

b. Stratification

Informed consent includes all of the following except: a. Disclosure of appropriate alternative procedures or courses of treatment b. A description of how confidentiality will be maintained c. A statement that participation is voluntary but that a person cannot withdraw from the research study d. Information on who to contact for study-related injuries

c. A statement that participation is voluntary but that a person cannot withdraw from the research study

Which of the following statements is not correct regarding case-control studies? a. Case control studies may be affected by bias in the assessment of the exposure b. Incident cases are preferable to prevalent cases for causal research c. Case control studies are very efficient for rare exposures d. Case control studies are more cost-effective than preospective cohort studies

c. Case control studies are very efficient for rare exposures

An analysis that includes all subjects who were randomized to the treatment and comparison groups, regardless of whether they received or completed their assigned study protocol, is: a. Run-in period b. Efficacy Analysis c. Intent-to-treat analysis d. Comparability

c. Intent-to-treat analysis

You are leading a research team to study the association between infection with Human Papillomavirus (HPV) and the development of oral cancer in Florida. You opt to carry out a case-control study. Which of the following is an advantage of this study design over a cohort study? a. It provides temporal information on the exposure and outcome b. It uses relative risk as an outcome measurement c. It is efficient for rare diseases d. It is more expensive to conduct than a cohort study

c. It is efficient for rare diseases

It is critical to reduce loss to follow up as much as possible in a cohort study because: a. Loss to follow-up is a waste of money b. Loss to follow-up will affect the reputation of the researcher c. Loss to follow-up can affect the validity of a study

c. Loss to follow-up can affect the validity of a study

The main difference between a case control study and a retrospective cohort study is that... a. A retrospective cohort study starts by grouping participants by disease status b. There is no difference between these two study designs c. A case control study starts by grouping participants by exposure status d. A case control study starts by grouping participants by disease status

d. A case control study starts by grouping participants by disease status

In a journal article, where can you find information about how data was collected? (Choose all correct answers) a. Conclusion b. Discussion c. Introduction d. Methods e. Results

d. Methods

Which of the following is not usually a section of a journal article? a. Abstract b. Conclusion c. Discussion d. Opinion e. Results f. Introduction g. Methods

d. Opinion

An article was recently published on the relationship between caffeine consumption during pregnancy and low birth weight. The article was based on the results of a case-control study. As you know, caffeine is present in a wide variety of beverages, foods, and medications, including coffee, tea, and colas. The following statement has been taken from the introduction and results sections of the article. Select the Hill's guideline that best describes the statement. Caffeine exposure during pregnancy could have a harmful effect because caffeine interferes with cell division, metabolism, and growth. a. Strength of the Association b. Biological Gradient c. Consistency d. Plausibility e. Temporality

d. Plausibility

A case-control study was performed to determine whether head injury was associated with an increased risk of brain tumors in children. A total of 200 cases with brain cancer were identified from the state cancer registry and 200 controls were recruited from the same neighborhoods where the cases lived. The mothers of the children filled out a questionnaire that asked them to describe their child's past history of head injury. The investigators found that the mothers of the children with brain tumors reported a past head injury for 70 of the cases while a past history of head injury was reported in 30 of the controls. What type of bias was most likely to have influenced the findings of this study? a. Surveillance, diagnostic, or referral bias b. Interviewer/recorder bias c. Length bias d. Recall bias

d. Recall bias

I'm conducting a randomized trial and it is essential that my two groups are comparable by age and gender. The best way to ensure that this happens is to: a. Randomly assign subjects to treatment groups from the whole population b. Personally choose exactly which people will be in each treatment group c. Assign all the women to the treatment group and all the men to the comparison group d. Stratify by age and gender before randomizing

d. Stratify by age and gender before randomizing

The document published in 1979 by the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research that outlines basic ethical principles of research is: a. The Nuremberg Code b. The Declaration of Helsinki c. HIPAA d. The Belmont Report

d. The Belmont Report

An article was recently published on the relationship between caffeine consumption during pregnancy and low birth weight. The article was based on the results of a case-control study. As you know, caffeine is present in a wide variety of beverages, foods, and medications, including coffee, tea, and colas. The following statement has been taken from the introduction and results sections of the article. Select the Hill's guideline that best describes the statement. Four prior case-control studies and three cohort studies of caffeine intake during pregnancy have shown an increased risk of low birth weight infants among women who consumed high amounts of caffeine. a. Strength of the Association b. Biological Gradient c. Temporality d. Plausibility e. Consistency

e. Consistency

An article was recently published on the relationship between caffeine consumption during pregnancy and low birth weight. The article was based on the results of a case-control study. As you know, caffeine is present in a wide variety of beverages, foods, and medications, including coffee, tea, and colas. The following statement has been taken from the introduction and results sections of the article. Select the Hill's guideline that best describes the statement. In the current study, there was a four-fold increased risk (OR=4.0) of giving birth to a low birth weight infant among women who drank caffeine during pregnancy compared to women who did not consume any caffeine during pregnancy. a. Temporality b. Biological Gradient c. Analogy d. Consistency e. Strength of the Association

e. Strength of the Association

Hill's guideline that the cause must precede the disease is known as: a. Experiment b. Specificity c. Biological Gradient d. Analogy e. Strength of the Association f. Temporality

f. Temporality

Because subjects in case-control studies are selected based on their disease status, we can no longer estimate the _____ of the disease/outcome directly. We can estimate the _____ to assess the association between outcome and exposure in a case-control study by dividing the _____ of the exposure in cases and controls.

risk; odds ratio; odds

Use your knowledge of the sufficient-component causal model to answer the phrase with one of the following terms: sufficient cause, component cause, necessary cause The completion of this type of cause is synonymous with the occurrence of disease. _____ Blocking the action of this type of cause will prevent all cases of disease by all causal mechanisms. ______

sufficient cause; necessary cause

The ratio of the probability of an event occurring to that of it not occurring is known as _____.

the odds

Consider each of the following scenarios and state whether or not the variable in question is a confounder. A study of the risk of pulmonary hypertension among women who take diet drugs to lose weight. The crude relative risk of pulmonary hypertension comparing diet drug users to non-users is 17.0 and the age adjusted relative risk is 5.0. Is age a confounder in this study? _____ (Response options: Yes or No) A cohort study of liver cancer among alcoholics. Incidence rates of liver cancer among alcoholic men are compared to a group of non-alcoholic men. Is gender a confounder in this study? _____ (Response options: Yes or No). A case-control study of the risk of beer consumption and oral cancer among men. In this study, cigarette smoking is associated with beer consumption and is a risk factor for oral cancer among both beer drinkers and nondrinkers. Is cigarette smoking a confounder in this study? _____ (Response options: Yes or No).

yes; no; yes