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Interaction Contrast Disease Rates for Assessing Synergism (or Antagonism) in Multifactor—Multilevel Disease Risks
Author(s) -
Rao B. Raja,
Enterline Philip E.
Publication year - 1984
Publication title -
biometrical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 63
eISSN - 1521-4036
pISSN - 0323-3847
DOI - 10.1002/bimj.4710260702
Subject(s) - contrast (vision) , disease , econometrics , antagonism , mathematics , statistics , medicine , computer science , artificial intelligence , receptor
Abstract In the present paper, the two‐factor‐two‐level disease risk case is briefly reviewed. We have defined, what we call, the marginal effect of an agent. This is the effect of an agent in the presence of a second agent. It is noted that the two agents are synergistic (or that synergism is present) if the marginal effect of an agent exceeds its individual effect. The difference ME(A) — E(A alone) is called the effect S A of an agent. A simple relationship has been established between the effects S A and S B of the two agents and the HOGAN et al. (1978) measure D (also called the Interaction Contrast Disease Rate (ICDR) by HAMILTON (1979)). This relationship shows that there can be no assymmetries at the two dichotomous risk level. This discussion is extended to two disease risks each at several levels and to several disease risks each at several levels. In each case, a simple relationship has been established between the ICDR and the effects S Ai ( i = 1, 2,…, k ) of these disease risks. Several numerical examples are worked out to illustrate the result.