I would caution that risk factors, because they usually come from observational studies that  cannot prove cause and effect, are better defined as factors that are associated with an increase in risk. This may sound like epidemiology semantics, but I think it's an important distinction. Indeed, many risk factors could well be simply markers of increased risk, or confounders, just as prognostic factors are (There is also the issue of the causal pathway, which I won't get into here.) In addition, the term may reflect the fact that most non-infectious diseases (and some infectious ones as well) probably have multiple contributing risk factors.

Emily DeVoto, PhD

On Mon, Sep 15, 2008 at 10:17 AM, Cristian Baicus <[log in to unmask]> wrote:
A risk factor is always a causal factor, while a prognostic factor has only
to be associated with a prognosis, not necessary to cause it; it can be only
a "marker" of that prognosis (so it can be a ... confounder, too).

cristian baicus

dr. Cristian Baicus
Spitalul Colentina
Clinica de Medicina Interna
Sos. Stefan cel Mare 19-21
sect. 2
020125 BUCURESTI
Romania
Mobil: 0788302355
[log in to unmask]
www.baicus.ro

----- Original Message ----- From: "Christian Lerch" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, September 15, 2008 11:39 AM
Subject: Re: Examples of risk factors vs prognostic factors



A common (?) view is that risk factors alter (usually increase) the probability of developing or aquiring a disease, while prognostic factors alter (usually increase) the probability of having an unfavourabale outcome of this disease: death, higher morbidity, more adverse effects, recurrence...
Some risk factors are also prognostic factors.

Examples:
Presence of BRCA1/2 is a risk factor because it increases the probability of developing breast cancer.

Higher number of affected lymph nodes is a prognostic factor because it increases the probability of having an unfavourable outcome (death).

Age might be both a risk and a prognostic factor.

HTH,
Christian

On Mon, 15 Sep 2008 00:55:56 -0400
"Feddern-Bekcan, Tanya" <[log in to unmask]> wrote:

Hello, everyone.  Could you please give me some examples of risk factors
and prognostic factors and how to differentiate between the two?  For
example, having the breast cancer gene, having a family history of
breast cancer, being a heavy smoker, etc.  This is for PICO-writing.



Thank you,


Tanya

Tanya Feddern-Bekcan, MLIS, AHIP, MOT, OTR/L
http://www.geocities.com/nqiya/libraryarticles.html
<http://www.geocities.com/nqiya/libraryarticles.html>  formerly Tanya
Feddern
305.243.6648 - [log in to unmask] - 305.325.9670 (fax) EBM Theme
Co-Director & Reference and Education Librarian Louis Calder Memorial
Library - University of Miami Miller School of Medicine

"A library without a librarian is a reading room."-- Jenny Garcia of the
University of Wyoming, MLS, AHIP


dr. Cristian Baicus
Spitalul Colentina
Clinica de Medicina Interna
Sos. Stefan cel Mare 19-21
sect. 2
020125 BUCURESTI
Romania
Mobil: 0788302355
[log in to unmask]
www.baicus.ro



--
Emily DeVoto
Independent Health Care Consultant
http://health-counterspin.blogspot.com