Titre :
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Controls who experienced hypothetical causal intermedi hould not be excluded from case-control studies. (1999)
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Auteurs :
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C. POOLE
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Type de document :
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Article
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Dans :
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American journal of epidemiology (vol. 150, n° 6, 1999)
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Pagination :
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547-551
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Langues:
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Anglais
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Mots-clés :
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Cancer
;
Rectum
;
Tabagisme
;
Facteur risque
;
Epidémiologie
;
Méthodologie
;
Homme
;
Appareil digestif [pathologie]
;
Intestin [pathologie]
;
Tumeur bénigne
;
Côlon
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Résumé :
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[BDSP. Notice produite par INIST R0xwkH27. Diffusion soumise à autorisation]. It has been suggested that controls with adenematous polyps of the colon and rectum should be excluded from case-control studies of cigarette smoking and colorectal cancer. A claim has been made that the presence of such controls creates a bias toward the null. The polyps are an intermediate step in a hypothetical causal pathway between the exposure and the disease. Thus, the recommendation logically extends to the exclusion of all controls who experienced hypothetical causal intermediates from all case-control studies. It is shown, in the simple case of an exposure that acts solely through the pathway involving the intermediate, that such exclusions create a bias away from the null. The rationale for recommending the detrimental exclusions appears to stem from a variant of the "trohoc fallacy" : the mistaken view of case-control studies as comparisons between diseased and healthy groups and not as comparisons between groups that differ by exposure.
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