In the logistic regression model of potential predictors of MDD, none of the inflammatory markers (IL-4 [p = 0.62] and IL-6 [p = 0.29]) or any other variables (cardiovascular diseases [p = 0.71], hypothyroidism [p = 0.39] or age [p = 0.05]) remained associated with MDD, with the single exception of DM2 (OR = 6.54; 95% confidence interval [95%CI] = 1.06-57.08; B = 2.05 ± 1.01; p = 0.03). This evidence concerns the gene IL4 and major depressive disorder.