Fig. 1From: Structural equation modeling of immunotoxicity associated with exposure to perfluorinated alkylatesStructural equation model for the association between the latent PFAS concentration and the antibody concentration adjusted for covariates (Additional file 1: Model 1). The model is shown for the relation between latent PFOA (circle) measured by the 5- and 7-year observed concentrations (left squares) and anti-diphtheria (right square). “Covariates” (middle square) are age, sex, and booster type that predicts the latent variable and the two antibody concentrations additively and linearlyBack to article page