Figure 3 shows the linear relationship (P for nonlinearity: overall = 0.318, CRP ≥ 5 mg/L = 0.007, CRP < 5 mg/L = 0.753, men = 0.381, women = 0.214) between serum magnesium and depression, which was statistically significant in the overall sample, in subjects with CRP levels ≥ 5 mg/L, and in men (p value: overall = 0.030, CRP ≥ 5 mg/L = 0.039, men = 0.016, respectively). Here, CRP is linked to major depressive disorder.