Figure 1.
Model of the potential mediating effect of BMI on the association betweensmoking categories and atopic sensitization. The figure shows how to estimate the indirect effects through the potential mediator, of one smoking category (X1, X2, X3 and X4) on atopic sensitization compared to non-smoking category. Total effects (c paths) represent the overall association of a smoking category with atopic sensitization. Mediating effect occurred when the overall association could be partially (or fully) explained by the potential mediator (BMI). Association of the potential mediator with each smoking category (a paths) and the association with atopic sensitization independent of each smoking category were estimated. The products of abs (a1b, a2b, a3b, a4b) were used for estimating the indirect effects of BMI on the association between each smoking category and atopic sensitization. The “c” paths’ represent the direct effects of each smoking category and atopic sensitization.