Table 1. Baseline clinical characteristics of the subjects.
| Characteristic | Total subjects (n = 394) |
| Age (years) | 59.4±10.5 |
| Men, n (%) | 179 (45.4) |
| Diabetic duration (years) | 12.2±6.7 |
| Alcohol (yes, %) | 94 (23.9) |
| Smoking (yes, %) | 69 (17.5) |
| BMI (kg/m2) | 24.8±3.2 |
| Hypertension (yes, %) | 201 (51.0) |
| Diabetic retinopathy (yes, %) | 109 (27.7) |
| Diabetic neuropathic symptom (yes, %) | 86 (21.8) |
| Diabetic nephropathy (yes, %) | 132 (33.5) |
| Duration of metformin use (months) | 82.6±49.4 |
| Daily dose of metformin (mg) | 1305.5±449.4 |
| Hypertensive medication (yes, %) | 242 (61.4) |
| Use of statin (yes, %) | 212 (53.8) |
| Over-the-counter multivitamin(yes, %) | 46 (11.7) |
| Calcium supplement (yes, %) | 18 (4.6) |
| H2 blocker or PPI (yes, %) | 30 (7.6) |
| FBS (mg/dL) | 145.5±53.9 |
| Creatinine (mg/dL) | 0.8±0.2 |
| TC (mg/dL) | 166.9±37.4 |
| TG (mg/dL) | 131.5±115.9 |
| HDL-cholesterol (mg/dL) | 49.0±23.3 |
| LDL-cholesterol (mg/dL) | 95.9±40.7 |
| HbA1c (%) | 7.8±1.5 |
| Vitamin B12 deficiency, n (%) | 56 (14.2) |
| Vitamin B12 (pg/mL) | 638.0±279.6 |
| Serum folate (ng/mL) | 9.9±5.7 |
| Anemia*(yes, %) | 61 (15.5) |
| Hemoglobin (g/dL) | 13.9±5.3 |
| MCV (fL) | 89.0±5.0 |
| MCH (fL) | 30.7±1.8 |
| MCHC (fL) | 34.2±1.3 |
The data are shown as the means (SD) or n (%). *Hb<13 g/dL for men and <12 g/dL for women (WHO guidelines); BMI, body mass index; H2 blocker, histamine 2 receptor blocker; PPI, proton pump inhibitor; FBS, fasting blood sugar; TC, total cholesterol; TG, triglyceride; MCV, mean corpuscular volume; fL, femtoliter.