The LS means of SMI in the quartiles of total protein density (<13.2%, 13.2%~15.0%, 15.0%~17.2% and ≥17.2%) and vegetable protein density (<5.8%, 5.8%~7.5%, 7.5%~9.4% and ≥9.4%) were calculated after adjusting for total energy, fat density, age, gender, BMI, waist, albumin, hemoglobin, lymphocyte, smoking, alcohol use, exercise, diabetes mellitus, and hypertension. The gene discussed is ALB; the disease is diabetes mellitus.