The Epidemiological Approach Flashcards
Distinguish between epidemiology and clinical medicine.
What are the 2 ways we could investigate the relationship between smoking and lung cancer? Which is better?
Epidemiology: finding causes of disease and preventing disease. (Jump from individual to group - find other people with the same disease to see what makes them different)
Clinical medicine: diagnosis and treatment
Prospective (cohort) study: ID 4000 ppl and follow-up for 10yrs to see if smokers have higher incidence of LC BUT expensive, lengthy, numbers still too small to draw a firm conclusion. Can use retrospective (case-control) study: ask ppl with and without LC about smoking habits
Look at the data. What could you say about the liklihood of being a non-smoker and having or not having lung cancer?
People without LC are 15 x more likely to be a non-smoker than people with LC. (And thus people with LC are 15 x more likely to be a smoker than people without LC)
Heart disease can be prevented with three drugs:
anti-platelet drug (aspirin) prevents 30%
cholesterol lowering drug (statin) prevents 60%
blood pressure lowering drug prevents 20%
What % of the disease would be prevented if all 3 drugs were given together and they act independantly?
100 cases of disease. 30 would be prevented by aspirin leaving 70, of which 42 (60%) would be prevented by the statin, leaving 28 of which 6 (20%) would be prevented by the blood pressure lowering drug, leaving 22. So 78% would be prevented (30 + 42 + 6).
Define the cause of a disease.
A factor that is associated with the disease so that if the intensity or frequency of the factor in a population is changed, the frequency of the disease also changes.
