Model 2 was further adjusted for hypertension and diabetes, physical activity level, anxiety and depression, smoking and drinking status, social support, energy intake, and dietary pattern derived from IL-6 (p-for-trend = 0.026), and it was found that the third quartile of DP2 significantly increased the CI risk compared to patients in the first quartile of DP2 (AOR 14.54, 95% CI 1.40–151.13). This evidence concerns the gene IL6 and major depressive disorder.