In Model 3, IL-6 levels were significantly associated with FAB score with adjustment for age (β = −0.16; 95% CI: −0.19 to −0.14), sex, educational level (β = 0.41; 95% CI: 0.37 to 0.45), BMI (β = −0.04; 95% CI: −0.07 to −0.01), depression (β = −0.76; 95% CI: −1.2 to −0.32), LDL Cholesterol, AST and RBC. This evidence concerns the gene IL6 and major depressive disorder.