Table 1. Participant characteristics.
| Obese (n = 27) | Non-obese (n = 20) | Group Comparisons | |||||
|---|---|---|---|---|---|---|---|
| Mean (S.D.) | Range | Mean (S.D.) | Range | Test Statistic | p-value | Effect Size | |
| BMI (kg/m2) | 39.90 (4.76) | 33.2–51 | 22.42 (2.40) | 18.6–27.7 | U 45 = 217 | <0.001*** | 0.85 |
| PBF | 48.67 (4.04) | 39.7–55.6 | 32.74 (5.87) | 20.8–43.6 | U 45 = 217 | <0.01** | 0.83 |
| Age (years) | 31.5 (6.61) | 20–40.9 | 28.64 (5.28) | 21.0–39.7 | U 45 = 408 | 0.12 | 0.23 |
| Education (years) | 14.96 (1.91) | 12–18 | 15.90 (1.39) | 13–18 | U 45 = 578 | 0.11 | 0.22 |
| Disposition Index | 123.68 (71.95) | 54.4–288.8 | 276.61 (172.24) | 74.6–758.4 | F 1,41 = 24.22 | <0.001*** | 0.37 |
| Matsuda ISI | 4.05 (2.97) | 1.2–10.5 | 10.02 (5.97) | 3.3–21.4 | F 1,41 = 22.97 | <0.001*** | 0.36 |
| Phi Total | 36.36 (15.71) | 18.3–93.2 | 28.69 (7.46) | 16.0–41.2 | F 1,41 = 4.14 | 0.05* | 0.09 |
| Striatal D2R BP ND | 10.12 (1.34) | 8.2–13.4 | 10.20 (1.20) | 8.6–12.3 | F 1,38 = 1.98 | 0.17 | 0.05 |
| DRD AuC | .52 (.27) | .14–.98 | .55 (.29) | .05–.98 | F 1,39 = 0.00 | 0.97 | 0.00 |
| PRD AuC | .22 (.13) | .02–.50 | .20 (.11) | .02–.42 | F 1,39 = 0.56 | 0.46 | 0.01 |
| Gender Distribution | 23 Female, 4 Male | 15 Female, 5 Male | χ 2(1, N = 47) = 0.75 | 0.39 | 0.13 | ||
| Ethnic Distribution | 13 Wh, 13 Bl, 1 Hi | 16 Wh, 2 Bl, 1 Hi, 1 Biracial | χ 2(1, N = 47) = 3.41 | 0.07 † | 0.27 | ||
BMI, body mass index; ISI, insulin sensitivity index; DRD, delayed reward discounting; PRD, probabilistic reward discounting; D2R, dopamine D2 receptor; BPND, non-displaceable binding potential; NAc, nucleus accumbens; Wh, white; Bl, black; Hi, Hispanic.
*, p≤0.05
**, p≤0.01
***, p≤.001
†, p = 0.07 for comparison between obese and non-obese