When depression score was treated as a binary variable, serum magnesium levels were statistically negatively associated with depression scores (OR = 0.37; 95% CI = 0.16, 0.87; p = 0.022), and individuals with CRP levels ≥ 5 mg/L (compared to those with CRP levels < 5 mg/L) had odds ratios (ORs) of depression greater than 1 (OR = 2.19; 95% CI = 1.35, 3.55; p = 0.002). This evidence concerns the gene CRP and major depressive disorder.