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This informative guide explores causal relationships in epidemiology, including disease distribution and prevention measures. Understand the significance of associations and how to evaluate causation in public health research.
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RR = 7 Cause Is this association causal? Intro to Epidemiology – Investigation 3-2: Cause
Hypotheses 1 How is this disease distributed? 2 Is there an association? Why did the exposure and the disease turn up together? 3 Is the association causal? 4 What should be done to prevent the disease? 5 Did the prevention strategy work? Where are we and where are we going? What’s my hypothesis? Did the exposure and the disease turn up together? Why did the exposure and the disease turn up together? Intro to Epidemiology – Investigation 3-2: Cause
No Outcome Total Outcome Exposure b a d c No Exposure Is the association causal? Intro to Epidemiology – Investigation 3-2: Cause
IS ASSOCIATED WITH IN Is the association causal? Intro to Epidemiology – Investigation 3-2: Cause
Review What do epidemiologists and mean when they say that two things, an exposure a disease, are associated with each other? Intro to Epidemiology – Investigation 3-2: Cause
No Outcome Outcome Exposure No Exposure Review Relative Risk Risks Count % or a b c d 10% or Compare Divide What do epidemiologists mean when they say two things, an exposure and a disease, are associated with each other? Intro to Epidemiology – Investigation 3-2: Cause
Relative Risk No Outcome Outcome Count 100 100% 100 0 100 Exposure 100 100 1 1% 1 99 100 No Exposure 100 Compare Divide Review Risks or a b c d or Did the exposure and the outcome turn up together? Were the exposure and the outcome associated? Intro to Epidemiology – Investigation 3-2: Cause
Relative Risk No Outcome Outcome Count 30 30% Exposure 30 70 100 100 1 30 30% No Exposure 30 70 100 100 Compare Divide Review Risks or a b c d 90 or Did the exposure and the outcome turn up together? Were the exposure and the outcome associated? Intro to Epidemiology – Investigation 3-2: Cause
Relative Risk No Outcome Outcome Count 30 30% Exposure 30 70 100 100 3 10 10% No Exposure 10 90 100 100 Compare Divide Review Risks or a b c d 90 or Did the exposure and the outcome turn up together? Were the exposure and the outcome associated? Intro to Epidemiology – Investigation 3-2: Cause
Review 1. Cause 2. 3. 4. 5. Intro to Epidemiology – Investigation 3-2: Cause
Review Intro to Epidemiology – Investigation 3-2: Cause
Review Epi Speak Cause Anything that produces an effect. Intro to Epidemiology – Investigation 3-2: Cause
1 O NoO X NoX Identify the cells of the 2 x 2 table in which there would be people if the exposure caused the disease. 2 x 2 Table a a bc d d Intro to Epidemiology – Investigation 3-2: Cause
Cigarette Labels Intro to Epidemiology – Investigation 3-2: Cause
Cigarette Labels “… Smoking Causes Lung Cancer ….” Intro to Epidemiology – Investigation 3-2: Cause
2 NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes Label a 2 x 2 table to test the hypothesis that cigarette smoking causes lung cancer. Cigarette smoking causes lung cancer. a bc d Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes Cigarette smoking causes lung cancer. a b a bc d c d Label a 2 x 2 table to test the hypothesis that cigarette smoking causes lung cancer. Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes Cell b … anything that produces an effect. b a bc d Smoking Causes Lung Cancer Label a 2 x 2 table to test the hypothesis that cigarette smoking causes lung cancer. Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes Time Cigarette smoking causes lung cancer. … anything that produces an effect. b a bc d Smoking Causes Lung Cancer X O Intro to Epidemiology – Investigation 3-2: Cause
AIDS No AIDS HIV No HIV Time HIV causes AIDS. … anything that produces an effect. b a bc d HIV Causes AIDS HIV AIDS Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes Time Cigarette smoking causes lung cancer. … anything that produces an effect. b a bc d Smoking Causes Lung Cancer Cigarettes Lung Cancer Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes X + X causes O. … anything that produces an effect. b a bc d Smoking Causes Lung Cancer X O Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes Genetic Susceptibility + Cigarette smoking causes lung cancer. … anything that produces an effect. b a bc d Smoking Causes Lung Cancer Cigarettes Lung Cancer Intro to Epidemiology – Investigation 3-2: Cause
No Measles Measles Measles Virus Measles Virus Causes Measles No Measles Virus No Immunity + Measles Virus Measles Measles virus causes measles. … anything that produces an effect. b a bc d Intro to Epidemiology – Investigation 3-2: Cause
1. NoLung Cancer Lung Cancer a bc d Smoked Cigarettes Did Not Smoke Cigarettes b 2. X X + + Time Time Time 3. X causes O. X O X O X O Intro to Epidemiology – Investigation 3-2: Cause
NoLung Cancer Lung Cancer Smoked Cigarettes Did Not Smoke Cigarettes X Lung Cancer O X X Cell c … anything that produces an effect. Smoking Causes Lung Cancer a bc d c Cigarettes Asbestos Radon Intro to Epidemiology – Investigation 3-2: Cause
3 O NoO X a bc d NoX Label the 2 x 2 table and identify the cells in which there would be people, if the exposure caused the disease. X causes O. Intro to Epidemiology – Investigation 3-2: Cause
4 O NoO X a bc d NoX Compare your answers to Parts 1 and 3. X causes O. Intro to Epidemiology – Investigation 3-2: Cause
O NoO X a bc d NoX Cigarette smoking causes lung cancer. Have you identified cell a? Have you identified cells b and c? Have you identified cell d? Compare your answers to Parts 1 and 3. Intro to Epidemiology – Investigation 3-2: Cause
5 Describe how you can have people in cells b and c and still put a label on a pack of cigarettes that reads “… smoking causes lung cancer ….” Cigarette smoking causes lung cancer. Have you mentioned time delay between exposure and outcome? Have you mentioned the possible need for another exposure? SURGEON GENERAL’S WARNING:Smoking Causes Lung Cancer, Heart Disease, Emphysema, and May Complicate Pregnancy Intro to Epidemiology – Investigation 3-2: Cause
6 Label a 2 x 2 table and identify the cells in which there would be people if the exposure caused the disease. Lack of fitness and physical activity causes heart attacks. a bc d Intro to Epidemiology – Investigation 3-2: Cause
NoHeart Attack Heart Attack Lack of Fitness No Lack of Fitness 6 Lack of fitness and physical activity causes heart attacks. a b a bc d c d Label a 2 x 2 table and identify the cells in which there would be people, if the exposure caused the disease. Intro to Epidemiology – Investigation 3-2: Cause
Epi Speak Epi Speak Multiple Causes A combination of causes or an alternative cause that produces the effect. Intro to Epidemiology – Investigation 3-2: Cause
7 Label a 2 x 2 table and identify the cells in which there would be people if the exposure caused the disease. Lack of supervision of small children causes lead poisoning. a bc d Intro to Epidemiology – Investigation 3-2: Cause
NoLead Poisoning Lead Poisoning Lack of Supervision No Lack of Supervision 7 Lack of supervision of small children causes lead poisoning. a b a bc d c d Label a 2 x 2 table and identify the cells in which there would be people if the exposure caused the disease. Intro to Epidemiology – Investigation 3-2: Cause
Explanations for Finding an Association 1. Cause 2. 3. 4. 5. Why would an exposure and an outcome turn up together? Intro to Epidemiology – Investigation 3-2: Cause
Investigation 3-2 has ended. CDC Cause Intro to Epidemiology – Investigation 3-2: Cause