Characteristics of the study population*
| Characteristics | NFG | IFG | Type 2 diabetes |
| n (%) | 1897 (59.5) | 858 (26.9) | 434 (13.6) |
| Age (years) | 58.4±6.0 | 58.6±6.0 | 59.7±5.7 |
| Men, n (%) | 789 (41.6) | 414 (48.3) | 216 (49.8) |
| Beijing residents, n (%) | 727 (38.3) | 564 (65.7) | 282 (65.0) |
| Urban residents, n (%) | 931 (49.1) | 402 (46.9) | 254 (58.5) |
| BMI (kg/m2) | 23.8±3.5 | 25.4±3.6 | 25.4±3.5 |
| Family history of diabetes†, n (%) | 181 (9.5) | 110 (12.8) | 142 (32.7) |
| Smoking status, n (%) | |||
| Non-smoker | 1230 (64.8) | 484 (56.4) | 263 (60.6) |
| Ex-smoker | 152 (8.0) | 111 (12.9) | 61 (14.1) |
| Current smokers | 515 (27.1) | 263 (30.7) | 110 (25.3) |
| Alcohol drinking, n (%) | 470 (24.8) | 302 (35.2) | 133 (30.6) |
| Physical activity | |||
| Low | 136 (7.2) | 74 (8.6) | 25 (5.8) |
| Moderate | 817 (43.1) | 324 (37.8) | 198 (45.6) |
| High | 944 (49.8) | 460 (53.6) | 211 (48.6) |
| Fasting glucose (mmol/l) | 5.06±0.36 | 6.01±0.34 | 8.94±3.02 |
| Fasting insulin (pmol/l) | 12.9 (9.4−17.5) | 15.1 (11.1−20.4) | 14.8 (10.3−22.4) |
| HbA1c (%) | 5.64±0.42 | 5.85±0.45 | 7.81±2.01 |
| Adiponectin (μg/ml) | 14.9 (9.0−23.3) | 12.4 (7.6−20.6) | 10.1 (5.5−17.2) |
| RBP4 (μg/ml) | 39.1±11.4 | 41.3±12.2 | 41.3±11.9 |
| PAI-1 (ng/ml) | 6.68 (2.25−15.4) | 11.8 (4.45−23.8) | 13.3 (5.5−25.6) |
| Resistin (μg/ml) | 8.56 (5.67−13.9) | 8.56 (5.92−14.4) | 8.86 (6.03−13.7) |
| CRP (mg/l) | 0.57 (0.30−1.27) | 0.79 (0.36−1.76) | 0.97 (0.46−2.37) |
| IL-6 (ng/l) | 0.96 (0.62−1.48) | 1.12 (0.72−1.65) | 1.26 (0.81−1.89) |
| TNF-αR2 (μg/l) | 1.62 (1.28−2.01) | 1.61 (1.22−1.99) | 1.64 (1.30−2.12) |
| Ferritin (g/l) | 0.12 (0.08−0.17) | 0.15 (0.10−0.20) | 0.17 (0.12−0.24) |
| Biomarkers risk score | 5.21 (3.40−7.18) | 6.74 (4.77−8.60) | 7.62 (5.86−9.26) |
* Data are means±SD, medians (IQR) or n (%), unless otherwise indicated.
† First-degree relatives (parents or siblings) had a history of diabetes.
BMI, body mass index; CRP, C-reactive protein; IFG, impaired fasting glucose; IL, interleukin; NFG, normal fasting glucose; PAI-1, plasminogen activator inhibitor-1; RBP4, retinol-binding protein 4; TNF-αR2, tumour necrosis factor α receptor 2.