When assessing a positive relationship between alcohol consumption and oral cancer using a case-control study, increasing the sample size of the study will result in which of the following
A.A lower p value
B.A greater odds ratio
C.A smaller 95% confidence interval
D.A & C only
The measure of the benefit to the population derived by modifying a risk factor is the:
A.risk difference
B.etiological fraction
C.population etiologic fraction
D.population risk difference
An approach to estimating the effects due to the single exposure factor is to compute the:
A.risk difference
B.etiological fraction
C.population etiologic fraction
D.population risk difference
A statistical association may be causal or noncausal. In addition, many diseases require that more than one factor be present for disease to develop. Examples of multiple causation models include:
A.web of causation
B.wheel model
C.pie model
D.all of the above
You are investigating the role of physical activity in heart disease and suggest that physical activity protects against having a heart attack. While presenting these data to your colleagues, someone asks if you have thought about confounders such as factor X. This factor X could have confounded your interpretation of the data if it
A.is a factor for some other disease, but not heart disease.
B.is a factor associated with physical activity and heart disease.
C.is a part of the pathway by which physical activity affects heart disease.
D.has caused a lack of follow-up of test subjects.
The strategy which is not aimed at reducing selection bias is:
A.development of an explicit case definition
B.encouragement of high participation rates.
C.standardized protocol for structured interviews.
D.enrollment of all cases in a defined time and region.
The purpose of a double-blind study is to
A.achieve comparability of cases and controls.
B.reduce the effects of sampling variation.
C.avoid observer and interviewee bias.
D.avoid observer bias and sampling variation.
Which of the following is not a method for controlling the effects of confounding in epidemiologic studies
A.Randomization
B.Stratification
C.Matching
D.Blinding
E.Restriction
Surgeons at Hospital A report that the mortality rate at the end of a one-year follow-up after a new coronary bypass procedure is 15%. At Hospital B, the surgeons report a one-year mortality rate of 8% for the same procedure. Before concluding that the surgeons at Hospital B have vastly superior skill, which of the following possible confounders would you examine?
A.The severity (stage) of disease of the patients at the two hospitals at baseline
B.The starting point of the one-year follow-up at both hospitals (after operation versus after discharge)
C.Difference in the post-operative care at the two hospitals
D.Equally thorough follow-up for mortality
E.All of the above
Sensitivity and specificity of a screening test refer to its:
A.reliability
B.validity
C.yield
D.repeatability
Lead time bias is best described as:
A.an apparently lower survival rate among persons screened compared to an unscreened group.
B.an actually longer survival time for persons identified during a screening program because they were given an effective treatment.
C.a similar survival time for persons identified during a screening program relative to persons who are diagnosed by clinical symptoms.
D.an apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease.
The adverse consequences of using a screening test which has a low specificity include:
A.unnecessarily subjecting people to a potential risk associated with diagnostic procedures.
B.possible psychological trauma that accompanies suspicion of a disease.
C.increased burden of further diagnostic services.
D.increased costs of the screening test.
E.all of the above
The degree of agreement between several trained experts refers to
A.internal consistency
B.repeated measures
C.concurrent validity
D.inter-judge reliability
A test that determines whether disease is actually present is a:
A.screening test
B.diagnostic test
C.reliability test
D.none of the above
A person with an inapparent infection
A.can transmit the infection to others.
B.is a danger to family members but not to others in the community.
C.never develops antibodies.
D.is of no epidemiologic importance.
The epidemiological triangle considers which factor(s) in the pathogenesis of disease:
A.agent
B.host
C.environment
D.all of the above
The Centers for Disease Control and Prevention published an article concerning the high rate of foot fungal disease in New Orleans. The article explains that there has been a high rate of foot fungal disease in New Orleans for decades. Foot fungal disease in New Orleans is best described as
A.epidemic
B.endemic
C.incident
D.pathogenic
An attack rate is an alternative incidence rate that is used when
A.describing the occurrence of food-borne illness or infectious diseases.
B.the population at risk increases greatly over a short time period.
C.the disease rapidly follows the exposure during a fixed time period.
D.all of the above
Host factors in the causation of disease include:
A.temperature and humidity
B.chemicals in the air, water, or food
C.genetic factors
D.altitude
An outbreak of salmonellosis occurred after an epidemiology department luncheon, which was attended by 485 faculty and staff. Assume everyone ate the same food items. Sixty-five people had fever and diarrhea, five of these people were severely affected. Subsequent laboratory tests on everyone who attended the luncheon revealed an additional 72. The attack rate of salmonellosis was:
A.13.4%
B.47.4%
C.28.2%
D.7.7%
Question 21 of 25
4.0 Points
An outbreak of salmonellosis occurred after an epidemiology department luncheon, which was attended by 485 faculty and staff. Assume everyone ate the same food items. Sixty-five people had fever and diarrhea, five of these people were severely affected. Subsequent laboratory tests on everyone who attended the luncheon revealed an additional 72 cases. The virulence of salmonellosis was:
A.13.4%
B.47.4%
C.28.2%
D.7.7%
E.3.6%
Which of the following examples involves indirect transmission of disease?
A.Malaria
B.Hepatitis caused by needle sticks
C.HIV/AIDS
D.Pneumoconiosis
E.A and B
The ability of an agent to cause disease in the infected host is referred to as:
A.infectivity
B.pathogenicity
C.virulence
D.toxigenicity
Community A receives its water from several sources. The water source responsible for causing an outbreak of disease X is unknown. The best evidence to determine which suspected water supply is responsible would be:
A.the identity of the water supply providing water to the largest proportion of cases.
B.the relationship between quantity of water consumed and the severity of attack for each individual.
C.the identity of the water supply that has the greatest opportunity for contamination during the epidemic.
D.the attack rates for disease X in those who did and did not drink from each water supply.
The secondary attack rate among children aged two to four years is:
A.18%
B.20%
C.33%
D.50%
E.60%