Association and Causation

University:
Franklin University
Course:
CAS BI 107 | Biology 1
Academic year:

2020
Views:

404

Pages:

12
Author:

NebulaNomad

PRINCIPLE OF EPIDEMIOLOGY ASSOCIATION AND CAUSATION Association and causation 2 frequent sequence of studies in human 3 The two-step process 4  We determine whether there is an association or correlation between an exposure and the risk of a disease  a. Studies of group characteristics: ecologic studies  b. Studies of individual characteristics: cohort, casecontrol, and other types of studies  If an association is demonstrated, we determine whether the observed association is likely to be a causal one. Confounding 5 Direct versus indirect causes 6 Types of Causal Relationships 7     (1) necessary and sufficient; very rare (2) necessary but not sufficient; e.g. tubercle bacillus (3) sufficient but not necessary; e.g. radiation or benzene exposure for leukemia (4) neither sufficient nor necessary; e.g. smoking for CHD NECESSARY AND SUFFICIENT 8 NECESSARY BUT NOT SUFFICIENT 9 SUFFICIENT BUT NOT NECESSARY 10 Evidence for a Causal Relationship 11 1. Temporal relationship 2. Strength of the association 3. Dose-response relationship 4. Replication of the findings 5. Biologic plausibility 6. Consideration of alternate explanations 7. Cessation of exposure 8. Consistency with other knowledge 9. Specificity of the association NEITHER SUFFICIENT NOR NECESSARY 12