Table 1. Physical and biochemical characteristics of the 24 monozygotic twin pairs.
| Pairs discordant for weight (n = 14) | Pairs concordant for weight (n = 10) | ||||
| Normal weight pairs (n = 5) | Overweight pairs (n = 5) | ||||
| Non-obese co-twin | Obese co-twin | p * | Both co-twins | Both co-twins | |
| BMI (kg/m2) | 25.4 (24.5, 26.1) | 30.4 (28.4, 32.5) | 0.001 | 21.5 (20.8, 23.7) | 29.3 (26.9, 30.4) |
| Percent body fat | 27.1 (23.3, 38.5) | 37.2 (32.6, 43.0) | 0.001 | 19.0 (13.9, 20.7) | 34.8 (29.9, 45.8) |
| Subcutaneous fat (cm3) | 2698 (2406, 3966) | 4846 (4376, 5821) | 0.001 | 1445 (1234, 1600) | 4162 (3675, 5917) |
| Intra-abdominal fat (cm3) | 527 (380, 685) | 1010 (827, 1183) | 0.001 | 452 (361, 614) | 1059 (626, 1500) |
| M value (mg·kg fat free mass−1·min−1) | 8.6 (6.6, 10.4) | 6.6 (4.9, 7.3) | 0.01 | 8.4 (6.2, 9.8) | 6.9 (5.7, 8.0) |
| Serum insulin (mU/l) | 5.0 (3.0, 8.0) | 9.0 (6.0, 11.0) | 0.02 | 5.5 (4.0, 6.0) | 9.5 (7.0, 10.0) |
| Serum total cholesterol (mmol/l) | 4.6 (4.1, 5.0) | 4.7 (4.3, 5.1) | 0.41 | 4.4 (3.9, 5.1) | 4.7 (4.4, 5.5) |
| Serum LDL-cholesterol (mmol/l) | 2.5 (2.1, 3.0) | 2.6 (2.4, 3.2) | 0.030 | 2.5 (1.5, 2.9) | 2.7 (2.3, 3.0) |
| Serum HDL-cholesterol (mmol/l) | 1.3 (1.2, 1.7) | 1.3 (1.0, 1.4) | 0.012 | 1.4 (1.1, 2.0) | 1.2 (1.1, 1.8) |
| Serum triglycerides (mmol/l) | 1.0 (0.7, 1.2) | 1.4 (0.9, 1.6) | 0.028 | 1.0 (0.8, 1.1) | 1.6 (0.7, 2.1) |
| Serum high sensitivity CRP (mg/l) a | 0.9 (0.2, 1.1) | 2.0 (0.9, 3.4) | 0.003 | 0.2 (0.1, 0.2) | 1.4 (0.5, 4.0) |
| Serum leptin (ng/ml) b | 15.1 (7.2, 25.3) | 24.1 (18.5, 39.1) | 0.003 | 4.8 (3.6, 6.1) | 17.7 (11.1, 39.4) |
| Serum adiponectin (µg/ml) b | 12.7 (9.0, 14.9) | 10.8 (6.8, 12.6) | 0.013 | 10.7 (9.2, 11.9) | 7.9 (6.9, 9.1) |
Data are median (interquartile range). *obese vs. non-obese co-twins, paired Wilcoxon's test. a n = 19 pairs. b n = 21 pairs.