Table 1.
Anthropometric and metabolic characteristics
| Nonobese | Obese | ||||||
|---|---|---|---|---|---|---|---|
| NGT n = 73 | IGT n = 28 | T2DM n = 97 | NGT n = 31 | IGT n = 29 | T2DM n = 110 | P value obese vs. nonobese | |
| Sex | 0.12 | ||||||
| Female | 42 | 14 | 36 | 19 | 17 | 64 | |
| Male | 31 | 14 | 61 | 12 | 12 | 46 | |
| Race/ethnicity | 0.11 | ||||||
| Caucasian | 38 | 13 | 37 | 17 | 10 | 35 | |
| Mexican American | 35 | 15 | 60 | 14 | 19 | 75 | |
| Age (years) | 40 ± 2 | 50 ± 2* | 53 ± 1* | 37 ± 2 | 41 ± 3# | 51 ± 1*§ | 0.73 |
| BMI (kg/m2) | 25.9 ± 0.3 | 27.5 ± 0.4* | 27.0 ± 0.2* | 37.0 ± 0.9# | 34.3 ± 0.6# | 35.4 ± 0.6# | <0.0001 |
| Waist (cm)† | 87.6 ± 1.5 | 98.4 ± 2.1* | 94.9 ± 1.1* | 109.7 ± 5.2 | 107.5 ± 3.1 | 109.3 ± 1. ± 2 | <0.0001 |
| HbA1c (%) | 4.9 ± 0.2 | 5.2 ± 0.4 | 7.8 ± 0.2*§ | 4.5 ± 0.4 | 4.9 ± 0.6 | 8.2 ± 0.2*§ | 0.007 |
| FPG (mg/dL) | 93 ± 1 | 104 ± 2 | 177 ± 5*,§ | 95 ± 1 | 99 ± 2 | 170 ± 4*§ | <0.02 |
| FPI (μU/mL) | 7.3 (3.1) | 10.8 (7.3)* | 12.3 (9.1)*§ | 11.8 (12.6)# | 13.4 (5.6)# | 18.4 (10.5)*§# | <0.0001 |
| F–C-peptide (ng/mL) | 1.4 ± 0.1 | 2.1 ± 0.2* | 2.2 ± 0.1* | 2.5 ± 0.3# | 2.3 ± 0.2 | 3.1 ± 0.1*§# | <0.0001 |
| F-FFA (mmol/L) | 0.62 ± 0.03 | 0.70 ± 0.05 | 0.69 ± 0.03 | 0.77 ± 0.04# | 0.75 ± 0.04 | 0.79 ± 0.02# | <0.0001 |
| HOMA-IR (mU/L × mmol/L) | 1.6 (0.6) | 2.8 (1.8)* | 5.2 (4.1)*§ | 2.5 (2.7)# | 3.3 (1.3) | 7.4 (4.3)*§# | <0.0001 |
| Rd (mg/kg ⋅ min) | 3.7 ± 0.3 | 2.9 ± 0.4* | 2.5 ± 0.1*§ | 2.3 ± 0.3# | 1.9 ± 0.2*# | 1.9 ± 0.1*§# | <0.0001 |
| Rd/SSPI (mg/kg ⋅ min/units/L) | 68 (36) | 45 (18)* | 34 (27)*§ | 31 (41)# | 31 (15)# | 25 (13)*§# | <0.0001 |
| Hepatic IR (EGP × FPI) | 13 (9) | 18 (15)* | 22 (17)* | 20 (14)# | 21 (8)# | 29 (15)*§# | <0.0001 |
| Adipose IR (FPI × F-FFA) | 4.2 (3.7) | 6.6 (5.3)* | 7.6 (6.8)* | 9.0 (11.7)# | 8.7 (5.3)# | 13.6 (7.6)*§# | <0.0001 |
| ISR-basal (pmol/min ⋅ m2) | 59 (46) | 81 (65)* | 90 (65)* | 102 (78)# | 112 (55)# | 127 (83)*§,# | <0.0001 |
| ISR-total (nmol/min ⋅ m2) | 35 (24) | 39 (22) | 20 (15)*§ | 49 (31)# | 41 (26) | 27 (21)*§# | 0.001 |
| ΔISR/ΔG ÷ IR | 47.2 (41.8) | 16.6 (8.6)* | 2.8 (3.7)*§ | 16.7 (31.0)# | 17.2 (12.4) | 2.6 (3.2)*§ | <0.0007 |
| ΔI/ΔG ÷ IR | 12.5 (10.9) | 5.1 (4.7)* | 0.9 (0.7)*§ | 9.2 (10.4) | 5.2 (2.7)* | 1.1 (0.9)*§# | 0.038 |
| MCRI clamp (L/min ⋅ m2) | 0.73 ± 0.02 | 0.62 ± 0.02* | 0.68 ± 0.02* | 0.60 ± 0.03# | 0.64 ± 0.02 | 0.67 ± 0.02* | <0.05 |
| Exogenous MCRI during clamp (L/min ⋅ m2) | 0.69 ± 0.02 | 0.56 ± 0.02* | 0.63 ± 0.02* | 0.55 ± 0.03# | 0.58 ± 0.02 | 0.61 ± 0.01* | <0.003 |
| MCRI fasting (L/min ⋅ m2) | 1.45 ± 0.1 | 1.30 ± 0.1 | 1.34 ± 0.1 | 1.29 ± 0.1 | 1.29 ± 0.1 | 1.17 ± 0.1 | 0.02 |
| MCRI OGTT (L/min ⋅ m2) | 0.91 ± 0.04 | 0.93 ± 0.08 | 1.28 ± 008*§ | 0.73 ± 0.06# | 0.76 ± 0.05 | 0.93 ± 0.04*§# | <0.0001 |
| RdIns (pmol/min ⋅ m2) | 285 ± 15 | 306 ± 23 | 185 ± 12*§ | 428 ± 38 | 386 ± 38 | 261 ± 18*§ | <0.002 |
Entries represent mean ± SEM or median (interquartile range) depending whether the variable was normally or not normally distributed. F-, fasting; FPG, fasting plasma glucose.
*
P < 0.05 vs. NGT.
§
P < 0.05 vs. IGT within nonobese and obese groups.
#
P < 0.05 obese vs. nonobese in each glucose tolerance group.
†
Data were available for 91 nonobese and 95 obese subjects.