Risk factor

A risk factor is a variable associated with an increased risk of diseaseor infectionbut risk factors are not necessarily causal. For example, being young cannot be said to cause measles, but young people are more at risk as they are less likely to have developed immunity during a previous epidemic.

Risk factors are evaluated by comparing the risk of those exposed to the potential risk factor to those not exposed. Let's say that at a wedding, 74 people ate the chicken and 22 of them were ill, while of the 35 people who had the fish or vegetarian meal only 2 were ill. Did the chicken make the people ill?

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Risk = \frac {\mbox{number of persons experiencing event (food poisoning)}} {\mbox{number of persons exposed to risk factor (food)}} </math>

So the chicken eaters' risk = 22/74 = 0.297
And non-chicken eaters' risk = 2/35 = 0.057.

Those who ate the chicken had a risk over five times as high as those who did not, suggesting that eating chicken was the cause of the illness. Note, however, that this is not proof. Statisticalmethods would be used in a less clear cut case to decide what level of risk the risk factor would have to present to be able to say the risk factor "causes" the disease (for example in a studyof the link between smoking and lung cancer).

The term "risk factor" was first coined by heart researcher Dr. Thomas R. Dawberin a landmark scientific paper in 1961, where he attributed specific conditions (blood pressure, cholesterol, smoking) to heart disease.

• Definitions of "risk factor" (web)de:Risikofaktor

es:Factor de riesgo lt:Rizikos veiksnys pt:Fator de risco cardiovascular

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Risk+factor Wikipedia article Risk factor.