Table 2.
Baseline characteristics by level of the insulinogenic index.
| Positive insulinogenic index | Nonpositive insulinogenic index | |||
|---|---|---|---|---|
| Insulinogenic index ≥ 0.4 (n = 828) |
Insulinogenic index < 0.4 (n = 561) |
ΔGlu0–30 ≤ 0 (n = 42) |
ΔIns0–30 ≤ 0 (n = 30) |
|
| Age (years) | 51.6 ± 7.0 | 52.9 ± 6.7∗ | 50.6 ± 7.1 | 50.2 ± 8.5 |
| Male gender (%) | 65.3 | 79.5∗ | 42.9∗† | 63.3 |
| Body mass index (kg/m2) | 24.3 ± 3.3 | 23.6 ± 2.9∗ | 22.4 ± 2.7∗ | 24.8 ± 4.3‡ |
| Fasting plasma glucose (mg/dL) | 92/96/101 | 94/99/106∗ | 88/91/95∗† | 92/98/108‡ |
| 30 min plasma glucose (mg/dL) | 126/143/162 | 150/168/186∗ | 76/81/88∗† | 132/163/182‡ |
| 1-hour plasma glucose (mg/dL) | 106/131/159 | 146/178/205∗ | 72/92/101∗† | 112/151/192∗‡ |
| 2-hour plasma glucose (mg/dL) | 96/109/126 | 105/123/146∗ | 81/92/111∗† | 90/120/142‡ |
| Fasting insulin (μIU/mL) | 3.1/4.3/6.2 | 2.6/3.3/4.3∗ | 2.8/4.2/4.7 | 2.4/3.3/6.2 |
| 30 min insulin (μIU/mL) | 29.2/40.2/58.3 | 13.7/19.1/24.1∗ | 13.7/20.1/32.9∗ | 0.8/1.4/2.1∗†‡ |
| 120 min insulin (μIU/mL) | 16.3/24.6/39.7 | 14.5/21.5/34.9∗ | 9.1/15.3/21.9∗ | 10.6/23.0/39.1 |
| HbA1c (%) | 5.2 ± 0.3 | 5.3 ± 0.4∗ | 5.1 ± 0.3† | 5.3 ± 0.4 |
| Glucose tolerance | ||||
| Normal glucose tolerance (%) | 62.2 | 39.4∗ | 92.9∗† | 46.7‡ |
| Impaired fasting glucose (%) | 32.1 | 49.8 | 7.2∗† | 43.3 |
| Impaired glucose tolerance (%) | 13.2 | 30.9∗ | 2.4 | 30.0 |
| Current smokers (%) | 17.5 | 25.0∗ | 19.0 | 20.0 |
| Drinkers (%) | 59.9 | 71.3∗ | 42.9† | 63.3 |
| Antihypertensive medications (%) | 13.6 | 14.6 | 7.1 | 10.0 |
| Lipid-lowering medications (%) | 6.9 | 7.3 | 2.4 | 6.7 |
Data are expressed as mean ± standard deviation, 25/50/75th percentile values, or %. Characteristics among groups were compared using one-way ANOVA for continuous variables and chi-square tests for categorical variables with Bonferroni correction for multiple comparisons. ∗p < 0.05 compared to insulinogenic index ≥ 0.4, †p < 0.05 compared to insulinogenic index < 0.4, ‡p < 0.05 compared to ΔGlu0–30 ≤ 0. ΔGlu0–30 and ΔIns0–30, change in glucose and in insulin, respectively, over the first 30 min on the oral glucose tolerance test.