Table 1.
Study population: demographic characteristics
| Study participants |
Subjects with follow-up data
for body weight |
|||||
|---|---|---|---|---|---|---|
| All subjects1, 2 (n = 35) |
Male (n = 24) |
Female (n = 11) |
All subjects2, 3 (n = 16) |
Male (n = 12) |
Female (n = 4) |
|
|
|
|
|||||
| Age, yr | 30.2 ± 7.73 | 30.4 ± 8.34 | 29.6 ± 6.54 | 27.9 ± 7.59 | 27.8 ± 8.48 | 28.4 ± 4.89 |
| Body weight, kg | 92.4 ± 17.2 | 92.7 ±17.6 | 91.7 ± 17.0 | 95.7 ± 17.6 | 91.4 ± 16.2 | 108.6 ± 17.0 |
| Body mass index, kg/m2 | 32.2 ± 5.22 | 30.7 ± 4.45 | 35.4 ± 5.52 | 33.2 ± 6.51 | 30.6 ± 4.33 | 41.2 ± 5.62 |
| Body fat, % | 32.3 ± 7.70 | 28.1 ± 4.79 | 41.4 ± 3.85 | 32.8 ± 8.29 | 29.3 ± 5.95 | 43.3 ± 3.99 |
| Fasting plasma glucose, mg/dl | 86.7 ± 10.4 | 85.3 ± 11.7 | 89.7 ± 6.1 | 83.9 ± 10.4 | 81.6 ± 10.4 | 90.8 ± 7.97 |
| 2h-plasma glucose, mg/dl | 128.0 ± 29.2 | 120.9 ± 27.7 | 143.5 ± 27.5 | 121.8 ± 31.9 | 119.8 ± 33.5 | 127.8 ± 30.1 |
| Fat mass, kg | 30.2 ± 9.89 | 26.6 ± 8.35 | 38.1 ± 8.54 | 32.2 ± 12.3 | 27.3 ± 8.91 | 47.0 ± 8.49 |
| Fat-free mass, kg | 62.2 ± 11.6 | 66.1 ± 10.2 | 53.6 ± 9.73 | 63.4 ± 9.27 | 64.1 ± 9.30 | 61.5 ± 10.3 |
| Glucose tolerance status4 | ||||||
| Normal glucose regulation | 23 (65.7%) | 20 (83.3%) | 3 (27.3%) | 12 (75%) | 10 (83.3%) | 2 (50%) |
| Impaired glucose regulation | 12 (34.3%) | 4 (16.7%) | 8 (72.3%) | 4 (25%) | 2 (16.7%) | 2 (50%) |
| Energy intake, kj/d5 (kcal/d) |
9402 ± 997 (2246 ± 238) |
9603 ± 949 (2294 ± 227) |
8970 ± 1029 (2143 ± 246) |
9536 ± 976 (2278 ± 233) |
9527 ± 1110 (2276 ± 265) |
9567 ± 470 (2286 ± 112) |
| 24h-respiratory quotient6 | 0.86 ± 0.04 | 0.86 ± 0.03 | 0.85 ± 0.06 | 0.86 ± 0.03 | 0.87 ± 0.03 | 0.85 ± 0.03 |
| 24h-energy expenditure,
kJ/d (kcal/d) |
9642 ± 1007 (2304 ± 241) |
9946 ± 682 (2376 ± 163) |
8992 ± 1319 (2148 ± 315) |
9847 ± 796 (2352 ± 190) |
9788 ± 728 (2338 ± 174) |
10052 ± 1335 (2401 ± 319) |
| Sleeping metabolic rate,
kJ/d (kcal/d) |
7036 ± 849 (1682 ± 203) |
7203 ± 846 (1721 ± 202) |
6601 ± 768 (1577 ± 184) |
6992 ± 612 (1671 ± 146) |
6880 ± 638 (1644 ± 153) |
7348 ± 402 (1764 ± 96) |
| Awake-and-fed thermogenesis,
kJ/d (kcal/d)7 |
2075 ± 689 (496 ± 165) |
2155 ± 766 (515 ± 183) |
1867 ± 432 (446 ± 103) |
2073 ± 452 (495 ± 108) |
2007 ± 490 (480 ± 117) |
2307 ± 230 (551 ± 55) |
| Resting metabolic rate,
kJ/d (kcal/d) |
7823 ± 1091 (1877 ± 263) |
8182 ± 1041 (1963 ± 249) |
7040 ± 756 (1690 ± 183) |
7853 ± 1039 (1884 ± 249) |
8073 ± 1061 (1939 ± 256) |
7192 ± 749 (1725 ± 180) |
| Carbohydrate oxidation,
kJ/d (kcal/d)8 |
4621 ± 1456 (1104 ± 348) |
5117 ± 889 (1222 ± 213) |
3701 ± 1901 (884 ± 454) |
5087 ± 777 (1215 ± 186) |
5307 ± 834 (1268 ± 199) |
4536 ± 28.6 (1084 ± 6.00) |
| Fat oxidation, kJ/d8 (kcal/d) |
3478 ± 1593 (831 ± 381) |
3326 ± 993 (795 ± 237) |
3760 ± 2433 (898 ± 581) |
3502 ± 1290 (839 ± 308) |
3229 ± 1152 (772 ± 275) |
4536 ± 1837 (1000 ± 439) |
All data reported as frequency (percentage) or mean ± SD.
Only healthy, non-diabetic (2h-plasma glucose < 200 mg/dl) individuals between 18 – 55 years old were included. Student’s t-test assured no difference in sphingolipid concentrations between Native Americans of full versus half Southwestern heritage, thus data were analyzed in the whole group of Native Americans.
Maximum sample size reported. May differ by phenotyping due to data availability (see Subjects and Clinical Assessment).
Median follow-up time: 6.68 years (0.26 – 12.4 years) with a body weight gain of 4.77 ± 13.2 kg (P < 0.05, equivalent to + 7.05 ± 19.1% compared to initial body weight) and an annual weight gain of 0.92 ± 2.84%.
For normal glucose regulation, fasting plasma glucose < 100 mg/dl and 2h-plasma glucose < 140 mg/dl, impaired glucose regulation at fasting plasma glucose 100 – 126 mg/dl and/or 2h-plasma glucose 140 – 199 mg/dl, in accordance with the American Diabetes Association guidelines (1).
Meals served at 8 AM, 11 AM, 4 PM, and 7 PM. Total energy intake during a 24-hour stay in a respiratory chamber. The intercept of the regression line between EE and SPA values measured from 11 AM till 1 AM provided the EE in the inactive state.
Awake-and-fed thermogenesis (AFT) (2), reflective of an individual’s thermogenesis from the sleeping state to the non-active, awake and fed state, and derived from the difference between EE in the inactive state and SMR.
Twenty-four hour respiratory quotient (24h-RQ), derived from the ratio of 24-hour carbon dioxide production and oxygen consumption (l), was extrapolated from each 15-minute time period to 24-hours.
After accounting for all-day urinary nitrogen excretion as a measure of protein oxidation, 24-hour fat and carbohydrate oxidation rates were calculated from the 24h-RQ. A maximum of 35 subjects were analyzed for possible associations with RMR, and 34, 30, and 27 volunteers for associations with 24h-EE and 24h-RQ, SMR, and AFT, respectively. Population characteristics are reported as mean ± SD.
1. Seino Y, Nanjo K, Tajima N, Kadowaki T, Kashiwagi A, Araki E, et al. Report of the committee on the classification and diagnostic criteria of diabetes mellitus. Journal of diabetes investigation. 2010;1(5):212–28.
2. Piaggi P, Krakoff J, Bogardus C, Thearle MS. Lower “awake and fed thermogenesis” predicts future weight gain in subjects with abdominal adiposity. Diabetes. 2013;62(12):4043–51.