HP_200_Risk_Factors

HP_200_Risk_Factors - 1 Risk Factors: What are they Risk...

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Unformatted text preview: 1 Risk Factors: What are they Risk Factors: What are they and what do they mean? and what do they mean? HP 200 September 5, 2006 GM Roybal, M.D., M.P.H. Overview: Overview: What is a risk factor? How are risk factors determined? Case Control Study Cohort Study Examples from the literature. Objective: Objective: To determine whether there is an excess risk/decreased risk of a certain disease in association with a certain exposure or characteristic. Risk - To expose to hazard or danger Risk = Incidence Risk Factor: Risk Factor: A reliable association between some factor (behavior, condition, etc.) and a given, disease, injury, or illness 2 Absolute Risk: Absolute Risk: The incidence of a disease in a population. Absolute Risk: Absolute Risk: Includes all people--both the exposed and the unexposed. Does not tell us whether the exposure in question is associated with increased risk of disease. Health, United States, 1996-7 Absolute Risk: Examples Absolute Risk: Examples 1995 USA Age-Adjusted 1995 USA Age-Adjusted Strokes 26.7 deaths/100,000 population Breast Cancer 21.0 deaths/100,00 population women Prostate Cancer 15.4 deaths/100,000 population men Heart Attacks 89.5 deaths/100,000 population How do we determine whether How do we determine whether a disease is associated with a a disease is associated with a certain exposure? certain exposure? 3 Use data from studies Use data from studies designed to answer question. designed to answer question. Case Control Studies Cohort Studies Cohort Studies: Cohort Studies: Investigator selects a group of exposed individuals and a group of non-exposed individuals and follows both groups to compare the incidence of disease over time. Can determine whether temporal link exists between exposure and disease. Cohort Studies: Cohort Studies: Cohort = Exposure Example: Example: Select 10,000 people 5,000 Smokers 5,000 Non-smokers Follow them over time--50 years. Determine the incidence of lung cancer over the study period in each group. 4 Lung Cancer in Smokers Lung Cancer in Smokers Cohort Cohort + Disease Disease Lung Lung Cancer Cancer- Disease Disease No Cancer No Cancer Total Total Exposed Exposed Smokers Smokers 1,200 1,200 (a) (a) 3,800 3,800 (b) (b) 5,000 5,000 (a+b) (a+b) Not- Not- Exposed Exposed Non- Non- Smokers Smokers 500 500 (c) (c) 4,500 4,500 (d) (d) 5,000 5,000 (c+d) (c+d) Lung Cancer in Smokers Lung Cancer in Smokers Cohort Cohort + Disease Disease Lung Lung Cancer...
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This note was uploaded on 02/28/2010 for the course HP 200 taught by Professor Roybal during the Fall '05 term at USC.

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HP_200_Risk_Factors - 1 Risk Factors: What are they Risk...

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