Glucose, insulin and derived indexes during OGTT in study participants
| Characteristics | Non-drinkers (N=1389) | Tea drinkers (N=948) | Green tea drinkers (N=499) | ||
| Description | P value | Description | P value | ||
| Plasma glucose level during OGTT (mmol/L) | |||||
| FPG | 6.0 (1.38) | 6.5 (1.69) | <0.001 | 6.5 (1.78) | <0.001 |
| PG30min | 10.2 (2.30) | 10.9 (2.52) | <0.001 | 11.0 (2.58) | <0.001 |
| PG1h | 11.7 (3.62) | 12.7 (3.88) | <0.001 | 12.8 (3.90) | <0.001 |
| PG2h | 10.1 (4.33) | 11.1 (4.79) | <0.001 | 11.2 (4.84) | <0.001 |
| PG3h | 7.2 (3.64) | 7.4 (4.04) | 0.970 | 7.4 (4.09) | 0.953 |
| Plasma insulin level during OGTT (μIU/mL) | |||||
| FIN | 10.8 (7.72) | 11.5 (7.89) | 0.009 | 11.3 (7.55) | 0.167 |
| IN30min | 65.8 (56.81) | 64.3 (64.37) | 0.035 | 61.9 (54.79) | 0.014 |
| IN1h | 86.9 (64.25) | 88.5 (72.53) | 0.561 | 86.6 (72.25) | 0.095 |
| IN2h | 96.0 (75.09) | 96.6 (75.11) | 0.847 | 95.2 (72.95) | 0.556 |
| IN3h | 49.1 (47.17) | 44.1 (43.62) | 0.002 | 42.6 (44.66) | <0.001 |
| HbA1c | |||||
| mmol/mol | 42.3 (10.51) | 45.0 (12.04) | <0.001 | 45.5 (12.90) | <0.001 |
| % | 6.0 (0.96) | 6.3 (1.10) | <0.001 | 6.3 (1.18) | <0.001 |
| Glucose tolerance categories, n (%) | <0.001 | <0.001 | |||
| Normal glucose tolerance | 460 (33.12) | 233 (24.58) | 110 (22.04) | ||
| Pre-diabetes | 420 (30.24) | 286 (30.17) | 154 (30.86) | ||
| Newly diagnosed diabetes | 509 (36.65) | 429 (45.25) | 235 (47.09) | ||
| OGTT-derived indexes | |||||
| Modified Matsuda index | 67.9 (45.5, 105.0) | 63.2 (42.1, 91.5) | <0.001 | 63.4 (43.2, 92.4) | 0.008 |
| HOMA-IR | 2.4 (1.5, 3.8) | 2.7 (1.8, 4.1) | <0.001 | 2.6 (1.8, 4.0) | <0.001 |
| HOMA-β | 78.6 (49.5, 126.3) | 72.8 (47.1, 116.2) | 0.017 | 68.5 (44.5, 110.4) | 0.002 |
| Stumvoll first-phase index | 828.2 (287.3, 1265.4) | 720.6 (13.0, 1190.5) | <0.001 | 658.8 (−5.1, 1158.1) | <0.001 |
| Stumvoll second-phase index | 247.8 (122.1, 349.2) | 225.7 (69.9, 346.7) | 0.005 | 213.5 (59.6, 334.6) | 0.001 |
Data are presented as mean (SD) or median (IQR) for continuous variables and n (%) for categorical variables.
FIN, fasting serum insulin; FPG, fasting plasma glucose; HbA1c, glycosylated hemoglobin A1c; HOMA-IR, homeostasis model assessment of insulin resistance; HOMA-β, homeostasis model assessment of β-cell function; IN1h, 1-hour postprandial serum insulin; IN2h, 2-hour postprandial serum insulin; IN3h, 3-hour postprandial serum insulin; IN30min, 30 min postprandial serum insulin; OGTT, oral glucose tolerance test; PG1h, 1-hour postprandial plasma glucose; PG2h, 2-hour postprandial plasma glucose; PG3h, 3-hour postprandial plasma glucose; PG30min, 30 min postprandial plasma glucose.