ALB and major depressive disorder: After adjusting for other potentially confounding factors, including smoking status, drinking, physical activity, BMI, albumin, serum iron, cholesterol, phosphorus, total protein, uric acid, serum vitamin D, sodium, potassium, hemoglobin, calcium intake, diabetes, arthritis, kidney failure, osteoporosis, thyroid disease, depression, the negative association remained significant (all P < 0.001).