Search results
Results from the WOW.Com Content Network
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 ...
Sun Hudson case: United States Texas 2004 An infant is removed from life support against his mother's wishes. Baby K: United States Virginia: 1992 The mother of an anencephalic baby wishes to keep the child on life support perpetually. Jesse Koochin: United States Salt Lake City: 2004 Parents wish to keep a child on life support. Spiro ...
There are various types of epidemiological studies in use: case-control studies, cohort studies, experimental controlled randomised trials (RCTs). Experimentation, in general, is a general scientific method of testing causal hypotheses by means of an intervention (controlled influence) in the natural course of the phenomenon under study.
Recall bias is of particular concern in retrospective studies that use a case-control design to investigate the etiology of a disease or psychiatric condition. [ 3 ] [ 4 ] [ 5 ] For example, in studies of risk factors for breast cancer , women who have had the disease may search their memories more thoroughly than members of the unaffected ...
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.
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 ]
Epidemiological (and other observational) studies typically highlight associations between exposures and outcomes, rather than causation. While some consider this a limitation of observational research, epidemiological models of causation (e.g. Bradford Hill criteria) [7] contend that an entire body of evidence is needed before determining if an association is truly causal. [8]
Notable bias (spin) has been reported in the interpretation of results of randomized control trials, although these study designs rank top in the level-of-evidence hierarchy. [36] [37] [38] Contrastingly, a study found low prevalence of bias in the conclusions of non-randomized control trials published in high-ranking orthopedic publications. [39]