Definition (NCI)

The ratio of the odds of an event occurring in one group to the odds of it occurring in another group, or to a samplebased estimate of that ratio.

Definition (NCI_NCIGLOSS)

A measure of the odds of an event happening in one group compared to the odds of the same event happening in another group. In cancer research, odds ratios are most often used in casecontrol (backward looking) studies to find out if being exposed to a certain substance or other factor increases the risk of cancer. For example, researchers may study a group of individuals with cancer (cases) and another group without cancer (controls) to see how many people in each group were exposed to a certain substance or factor. They calculate the odds of exposure in both groups and then compare the odds. An odds ratio of one means that both groups had the same odds of exposure and, therefore, the exposure probably does not increase the risk of cancer. An odds ratio of greater than one means that the exposure may increase the risk of cancer, and an odds ratio of less than one means that the exposure may reduce the risk of cancer.

Definition (MSH)

The ratio of two odds. The exposureodds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The diseaseodds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalenceodds ratio refers to an odds ratio derived crosssectionally from studies of prevalent cases.

Concepts 
Quantitative Concept
(T081)

MSH 
D016017

English 
Cross Product Ratio, CrossProduct Ratio, CrossProduct Ratios, Odds Ratios, Odds, Relative, Ratio, CrossProduct, Ratio, Risk, Ratios, CrossProduct, Ratios, Risk, Relative Odds, Risk Ratio, Risk Ratios, RELAT ODDS, odd ratio, odds ratio, risk ratio, Odds Ratio, relative odds 
Swedish 
Oddskvot

Finnish 
Kerroinsuhde

French 
OR (Odds Ratio), Rapport de chances, Risque relatif approximatif, Odds ratio 
Russian 
REZUL'TATOV PEREKRESTNYKH KOEFFITSIENT, KOEFFITSIENT RAZLICHII V CHASTOTE SLUCHAEV, RISKA KOEFFITSIENT, КОЭФФИЦИЕНТ РАЗЛИЧИЙ В ЧАСТОТЕ СЛУЧАЕВ, РЕЗУЛЬТАТОВ ПЕРЕКРЕСТНЫХ КОЭФФИЦИЕНТ, РИСКА КОЭФФИЦИЕНТ 
Japanese 
オッズ比, 乗積比, 危険比 
Italian 
Odds relativo, Rapporto crociato, Odds ratio 
Czech 
podíl šancí, poměr rizik, poměr šancí 
Polish 
Wskaźnik ryzyka, Iloraz szans 
Norwegian 
Odds ratio, Forholdet mellom to odds, Kryssproduktforhold, Oddsforhold, OR 
Spanish 
Desigualdad Relativa, Razón de Diferencia, Oportunidades Relativas, Razón de Posibilidades, Posibilidades Relativas, RO, Razón de Oportunidades, Odds Ratio, Producto Cruzado, Razón de Odds, Razón del Producto Cruzado, Cociente de Probabilidades Relativas, Posibilidad Relativa, Razón de Oposiciones, Razón de Productos Cruzados, Oportunidad Relativa, Razón de Riesgo, Relación ReferenciaProducto 
Portuguese 
Razão de Diferença, Odds Ratio, Razão de Produtos Cruzados, Taxa de Risco, Razão de Chances 
German 
CrossProduct Ratio, Odds Ratio, Risikoquotient 
Dutch 
Oddsratio, Ratio, crossproduct, Risicoratio 