Table 1.
Characteristics of the study sample stratified by oral glucose tolerance test (OGTT) classification: normal glucose tolerance (NGT), isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (i-IGT), combined IFG and IGT (IFG + IGT) and unknown type 2 diabetes (UT2D)
| Parameter | NGT | i-IFG | i-IGT | IFG + IGT | UT2D | p-value* |
|---|---|---|---|---|---|---|
| N (%) | 562 (56.1) | 237 (23.7) | 63 (6.29) | 90 (8.99) | 49 (4.90) | |
| Age (years) | 47 (39, 57) | 55 (46, 62) | 51 (41, 62) | 60 (52, 66) | 61 (54, 68) | < 0.001 |
| Women (%) | 52.7 | 32.5 | 55.6 | 31.1 | 34.7 | < 0.001 |
| Fasting serum glucose (mmol/l) | 5.1 (4.9, 5.3) | 5.9 (5.7, 6.2) | 5.2 (4.9, 5.4) | 6.0 (5.7, 6.3) | 7.2 (6.3, 7.5) | < 0.001 |
| 2-h postload serum glucose (mmol/l) | 5.3 (4.6, 6.2) | 6.0 (5.4, 6.8) | 8.4 (8.1, 9.1) | 8.8 (8.2, 9.5) | 11.6 (10.1, 13.9) | < 0.001 |
| Fasting insulin (µlU/ml) | 7.3 (5.2, 9.8) | 10.7 (7.3, 14.9) | 12.3 (7.1, 15.6) | 14.4 (10.8, 19.0) | 18.1 (13.5, 26.2) | < 0.001 |
| 2-h postload insulin (µlU/ml) | 37.0 (24.0, 57.0) | 50.0 (32.0, 73.9) | 97.6 (68.0, 160) | 131 (75.5, 167) | 132 (91.0, 187) | < 0.001 |
| Homeostasis model assessment-insulin resistance index (HOMA-IR) | 1.65 (1.18, 2.25) | 2.76 (1.91, 4.03) | 2.69 (1.68, 3.63) | 3.76 (2.86, 5.19) | 5.71 (3.51, 7.94) | < 0.001 |
| Glycated hemoglobin (%) | 5.2 (4.9, 5.4) | 5.4 (5.2, 5.6) | 5.3 (4.9, 5.6) | 5.6 (5.2, 5.9) | 6.0 (5.5, 6.4) | < 0.001 |
| Estimated glomerular filtration rate (ml/min/1.73 m2) | 93.9 (84.0, 103) | 89.5 (79.8, 97.4) | 87.7 (79.0, 100) | 84.9 (73.6, 96.3) | 88.1 (79.9, 96.1) | < 0.001 |
| Smoking (%) | ||||||
| Never | 40.8 | 38.4 | 41.3 | 40.0 | 49.0 | |
| Current | 23.5 | 18.6 | 11.1 | 14.4 | 14.3 | |
| Former | 35.8 | 43.0 | 47.6 | 45.6 | 36.7 | 0.080 |
| Alcohol consumption (g/day) | 4.25 (1.06, 13.4) | 8.79 (2.69, 22.9) | 2.90 (0.34, 12.9) | 6.33 (1.45, 17.8) | 4.69 (1.14, 12.9) | 0.003 |
| Weight (kg) | 76.2 (65.8, 85.4) | 84.4 (75.8, 94.0) | 81.9 (74.3, 95.0) | 89.3 (77.5, 96.1) | 90.9 (81.2, 98.5) | < 0.001 |
| Height (cm) | 171 (164, 179) | 174 (165, 180) | 170 (164, 175) | 172 (167, 178) | 173 (165, 176) | 0.064 |
| Body mass index (kg/m2) | 25.5 (23.3, 28.4) | 28.1 (25.8, 30.7) | 28.9 (26.6, 32.1) | 29.3 (27.1, 31.7) | 31.1 (27.7, 33.1) | < 0.001 |
| Body fat-free mass (kg) | 52.5 (45.4, 64.2) | 61.1 (51.6, 68.1) | 55.7 (50.0, 60.8) | 63.7 (53.2, 68.3) | 61.3 (51.9, 68.1) | < 0.001 |
| Body fat mass (kg) | 20.5 (16.5, 26.1) | 23.8 (19.5, 29.2) | 28.8 (20.3, 33.9) | 25.6 (20.9, 32.2) | 29.0 (23.2, 34.3) | < 0.001 |
| Waist circumference (cm) | 86.2 (78.0, 95.2) | 96.0 (88.1, 104) | 94.5 (89.5, 106) | 101 (94.0, 109) | 104 (93.2, 112) | < 0.001 |
| Systolic blood pressure (mmHg) | 120 (109, 130) | 126 (116, 137) | 128 (113, 139) | 133 (123, 144) | 137 (126, 150) | < 0.001 |
| Diastolic blood pressure (mmHg) | 74.0 (68.0, 80.0) | 77.5 (72.5, 83.5) | 78.5 (72.5, 86.0) | 81.5 (75.0, 89.0) | 80.5 (72.5, 86.5) | < 0.001 |
| Hypertension (%) | 23.1 | 45.2 | 52.4 | 67.8 | 77.6 | < 0.001 |
| Antihypertensive medications (%) | 14.1 | 33.3 | 25.4 | 44.4 | 55.1 | < 0.001 |
| Total cholesterol (mmol/l) | 5.40 (4.80, 6.07) | 5.60 (5.00, 6.38) | 5.70 (4.90, 6.07) | 4.16 (3.58, 4.80) | 5.70 (4.90, 6.50) | < 0.001 |
| Hypercholesterolemia (%) | 32.7 | 51.9 | 44.4 | 54.4 | 57.1 | < 0.001 |
| Lipid-lowering medication (%) | 4.27 | 10.6 | 14.3 | 3.33 | 18.4 | < 0.001 |
| Sedentarism (%) | 30.4 | 32.5 | 33.3 | 36.7 | 38.8 | 0.619 |
Data are medians (25th, 75th percentile) or percentage
Italic values indicate significance of p-value < 0.05
* p-values are based on the Chi-squared test for categorical variables and the Wilcoxon rank-sum (or Mann–Whitney) tests for continuous variables