Exam 7: Observational Studies

-Which term most accurately describes the following definition? "Analysis based on aggregated or grouped data; errors in inference may result because associations may be artifactually created or masked by the aggregation process." [Porta M,ed.A Dictionary of Epidemiology.New York: Oxford University Press; 2014.]

A researcher study of Baltimore neighborhoods showed that those with lower median household income experience a higher teen pregnancy rate.After reading this,someone concludes that a teenager with low income is more likely to get pregnant.What is the name of this mistaken conclusion?

A researcher study of Baltimore's neighborhoods showed that those neighborhoods with lower median household income experienced a higher teen pregnancy rate.What type of study design was used?

Which of the following biases is the most accurate explanation of the following situation? Epidemiologists are studying the possible relationship of cholera infections to drinking water.They conduct a case-control study and interview patients with cholera infection (cases) and persons without cholera infection (controls).A patient who was diagnosed with cholera often tries to identify all kinds of information related to drinking water.However,controls who were not diagnosed with cholera may not remember water they drink which is not from an unhygienic source.

To determine the prevalence of smoking among new students in a university,researchers conduct an anonymous survey at the first day of classes.They find that 22% of women and 28% of men were smokers.What type of study design was used?

Which term most accurately describes the following definition? "The observational epidemiological study of persons with the disease (or another outcome variable) of interest and a suitable control group of persons without the disease (comparison group,reference group)." [Porta M,ed.A Dictionary of Epidemiology.New York: Oxford University Press; 2014.]

A group of physicians working in the same hospital noticed a rare presentation of male young patients,free of typical risks factors,who presented to the hospital with rapidly progressing acute kidney failure.They documented their findings and described in detail the progression of disease.What is the study design described here?

Researchers wanted to provide additional support for a causal association between human papillomavirus (HPV) and oropharyngeal cancers.They performed an epidemiologic study of 100 patients with newly diagnosed oropharyngeal cancer and 200 control patients without cancer to evaluate associations between HPV infection and oropharyngeal cancer.[D'souza G,Kreimer AR,Viscidi R,et al.A study of human papillomavirus and oropharyngeal cancer.N Engl J Med.2007;356(19):1944-1956.] What kind of study design is this?

In the paper [Gold E,Gordis L,Tonascia J,et al.Risk factors for brain tumors in children.Am J Epidemiol.1979;109(3):309-319],investigators conducted a case-control study to identify risk factors for brain tumors in children.Children with brain tumors were compared with two groups of controls: The first control group,called normal controls,consisted of children with no known malignant disease.The second control group,called cancer controls,consisted of children with malignancies other than brain tumors.What is the benefit of using multiple controls in case-control studies?

Which term most accurately describes the following definition? "A study that examines the relationship between diseases (or other health outcomes) and other variables of interest as they exist in a defined population at one particular time." [Porta M,ed.A Dictionary of Epidemiology.New York: Oxford University Press; 2014.]

Epidemiologists tried to examine the distribution of multimorbidity,and of comorbidity of physical and mental health disorders,in relation to age and socioeconomic deprivation.They extracted data on 40 morbidities from a database of 1,751,841 people registered with 314 medical practices in Scotland as of March 2007.They analyzed the data according to the number of morbidities,disorder type (physical or mental),sex,age,and socioeconomic status.They defined multimorbidity as the presence of two or more disorders.[From Barnett K,Mercer SW,Norbury M,et al.Epidemiology of multimorbidity and implications for health care,research,and medical education.Lancet.2012;380(9836):37-43.] What is the proper classification for this study?

Which of the following statements is not the accurate description of selection bias in case-control studies?