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The greatest challenge in Epidemiology is establishing
causality. Given the limitations of epidemiologic studies, most of which cannot be
conducted in a laboratory setting, the best we can do is to establish epidemiologic
associations that would point to causality. In 1965, Sir A.B. Hill came up with 9 rules
for considering an association as causal. If an association can meet all 9 rules, then one
would have a stronger case for calling the association causal. These rules helped in
establishing a causal association between smoking and disease. |