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Relative Asbestos Effect Essay

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In addition to the multiplicativity index, the Relative Asbestos Effect (RAE) was used to evaluate the multiplicative interaction between smoking and asbestos. The RAE is the effect of smoking on the asbestos effect expressed as the ratio of the risk ratio due to asbestos exposure in non-smokers (RR01) to that in smokers (RR11). This measure is used to examine the heterogeneity of asbestos effect across categories of smoking status, to determine if there is effect-measure modification. If the asbestos effect is the same for non-smokers as for smokers, then the RAE is equal to one, whereas a value greater than one indicates that the effect of asbestos is greater in non-smokers than in smokers (negative multiplicative interaction), and vice versa (27). The equation of RAE is: RAE=RR01/RR11 …show more content…

For the interaction term, an odds ratio (95% CI) which is significantly greater (or less) than one, indicates a multiplicative interaction (29). The multiplicative interaction may also be evaluated with the likelihood ratio test comparing logistic regression models (or cox regression) with or without the interaction term (7,30). In epidemiologic studies, researchers examine the additive interaction or multiplicative interaction only for empirical reasons; and usually use the one that shows a better fit to the observations. In fact, statistical interactions are mostly evaluated as departure from multiplicativity, due to the statistical models used in the analyses (e.g. logistic regression), and that the models generate the multiplicative interactions results immediately. Usually, if authors are interested in the evaluation of the statistical interaction, they should report results as departure from additivity and

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