EPI 320 Lecture Notes - Lecture 11: Trisomy, Plasmodium Falciparum, Cardiovascular Disease
Document Summary
Epidemiologic def of a cause: factor without which some of the disease would not occur, rarely say an exposure the cause, but a cause. Both necessary and sufficient: no disease occurs without e, no other exposures are needed for disease to occur / every exposed gets the disease, down syndrome and trisomy 21 rare case. Necessary, but not sufficient: no disease occurs without e, other exposures needed / not everyone exposed gets the disease, ex: fetal alcohol syndrome. Sufficient but not necessary: exposure is capable of causing disease by itself, yet is not present in all cases of disease, ex: dna damage due to radiation male infertility. Neither necessary nor sufficient: not present in every case; don"t cause the disease in everyone exposed or without other exposures. 3: without, some disease wouldn"t occur, still are causes, in fact the most common category of cause, ex: type ii diabetes limb loss, smoking lung cancer.
