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Although in classical case–control studies, it remains true that the odds ratio can only approximate the relative risk in the case of rare diseases, there is a number of other types of studies (case–cohort, nested case–control, cohort studies) in which it was later shown that the odds ratio of exposure can be used to estimate the relative ...
Case-control studies compare the past exposure of cases with the disease to the past exposure of cases that did not have the disease. Because cohort studies require the entire population, case-control studies are a more cost-effective approach, using only the sample of workers with the disease to compare to a control. [5] [17]
A nested case–control (NCC) study is a variation of a case–control study in which cases and controls are drawn from the population in a fully enumerated cohort. [1] Usually, the exposure of interest is only measured among the cases and the selected controls. Thus the nested case–control study is more efficient than the full cohort design.
Stateville Penitentiary Malaria Study – a controlled study of the effects of malaria on the inmates of Stateville Penitentiary near Joliet, Illinois. Tuskegee Study of Untreated Syphilis in the Negro Male – a clinical study, conducted between 1932 and 1972 in Tuskegee, Alabama studied the natural progression of the disease if left untreated.
This study was a retrospective, case-control study that compared smoking habits of 684 individuals with bronchogenic carcinoma to those without the condition. [12] The survey included questions about smoking: starting age, 20 year tobacco consumption, brands used; as well as inquires about exposure to hazardous agents in the workplace, alcohol use, and causes of death for family members.
2b: Individual cohort study or low quality randomized controlled trials (e.g. <80% follow-up) 2c: "Outcomes" Research; ecological studies; 3a: Systematic review (with homogeneity) of case-control studies; 3b: Individual case-control study; 4: Case series (and poor quality cohort and case-control studies)
The case control study can, however, calculate the exposure-odds ratio, which, mathematically, is supposed to approach the relative risk as prevalence falls. Sander Greenland showed that if the prevalence is 10% or less, the disease can be considered rare enough to allow the rare disease assumption. [ 2 ]
When choosing a study design, many factors must be taken into account. Different types of studies are subject to different types of bias. For example, recall bias is likely to occur in cross-sectional or case-control studies where subjects are asked to recall exposure to risk factors. Subjects with the relevant condition (e.g. breast cancer ...