Table 2.
Comparison of GH and IGF-1, and non-skeletal measures of IGF-1 action (fat distribution and cardiovascular risk markers) between subjects with low vs. high BFR on biopsy (mean ± SD)
| Variable | All subjects n = 34 | Low BFR N = 17 | High BFR N = 17 | p value | |
|---|---|---|---|---|---|
|
| |||||
| GH and IGF-1 | GH (ng/mL) | 2.24 ± 2.63 | 2.28 ± 3.11 | 2.19 ± 2.13 | 0.92 |
| IGF-1 (ng/mL) | 127.4 ± 40.4 | 140.8 ± 35.9 | 114.0 ± 41.2 | 0.05 | |
| IGF-1 Z score | − 0.35 ± 1.09 | 0.15 ± 1.06 | − 0.86 ± 0.88 | 0.005 | |
| IGF-BP1 (pg/mL) | 34,295 ± 24,962 | 29,232 ± 20,775 | 39,357 ± 28,268 | 0.24 | |
| IGF-BP2 (ng/mL) | 245.9 ± 86.8 | 224.3 ± 85.4 | 267.5 ± 85.3 | 0.15 | |
| IGF-BP3 (μg/mL) | 6.21 ± 1.26 | 6.42 ± 1.13 | 5.99 ± 1.38 | 0.33 | |
| IGF-1/IGF-BP3 Molar ratio | 0.078 ± 0.020 | 0.083 ± 0.017 | 0.073 ± 0.022 | 0.15 | |
| Body composition | Height (cm) | 162.6 ± 7.6 | 161.8 ± 8.1 | 163.5 ± 7.1 | 0.52 |
| Weight (kg) | 58.2 ± 10.2 | 61.3 ± 11.7 | 55.1 ± 7.7 | 0.07 | |
| BMI (kg/m2) | 22.1 ± 3.6 | 23.5 ± 4.1 | 20.6 ± 2.4 | 0.02 | |
| DXA body composition | |||||
| Whole body fat (% Fat) | 35.0 ± 6.8 | 36.4 ± 6.5 | 33.6 ± 7.0 | 0.23 | |
| Trunk fat (% Fat) | 30.2 ± 7.7 | 32.2 ± 7.0 | 28.2 ± 8.1 | 0.13 | |
| Compartmental fat: CT slice at L4 | |||||
| Subcutaneous fat (mm2) | 20,383 ± 9633 | 22,578 ± 10,133 | 17,639 ± 8595 | 0.19 | |
| Visceral fat (mm2) | 5218±2135 | 5437 ± 2135 | 4943±2196 | 0.56 | |
| Marrow fat fraction assessed by MRS (N = 20) | Spine (L3; %) | 43.4 ± 13.1 | 42.2 ± 11.6 | 45.0 ± 15.4 | 0.67 |
| Femoral neck (%) | 71.1 ± 13.9 | 68.4 ± 12.7 | 74.4 ± 15.2 | 0.35 | |
| Serum markers associated with fat distribution | Leptin (ng/mL) | 19.3 ± 11.7 | 21.8 ± 12.9 | 16.8 ± 10.0 | 0.21 |
| Adiponectin (ng/mL) | 10,141 ± 3657 | 9209 ± 3251 | 11,074 ± 3894 | 0.14 | |
| CRP (mg/L) | 3.59 ± 14.20 | 6.06 ± 20.0* | 1.12 ± 1.87 | 0.32 | |
| IL-6 (pg/mL) | 1.97 ± 3.08 | 2.79 ± 4.13 | 1.16 ± 1.04 | 0.13 | |
| Total cholesterol (mg/dL) | 186 ± 35 | 183 ± 42 | 189 ± 27 | 0.66 | |
| HDL (mg/dL) | 77 ± 19 | 73 ± 15 | 82 ± 21 | 0.16 | |
| Triglycerides (mg/dL) | 76 ± 30 | 85 ± 33 | 68 ± 25 | 0.10 | |
| LDL (calculated; mg/dL) | 95 ± 32 | 94 ± 37 | 96 ± 28 | 0.86 | |
| Homocysteine (umol/L) | 9.1 ± 4.7 | 9.4 ± 6.5 | 8.8 ± 2.1 | 0.71 | |
| HOMA-IR | 0.977 ± 0.733 | 1.027 ± 0.668 | 0.926 ± 0.802 | 0.70 | |
GH growth hormone, IGF-1 insulin-like growth factor 1, BP binding protein, BMI body mass index, DXA dual-energy x-ray absorptiometry, MRS magnetic resonance spectroscopy, CRP C-reactive protein, IL-6 interleukin-6, HDL high-density lipoprotein, LDL low-density lipoprotein, HOMA-IR homeostatic model assessment of insulin resistance.
One subject with very high CRP of 83.5 mg/L contributed to the substantial variability in the Low BFR group; results of the between groups comparison did not differ after removal of this subject. With outlier removed mean CRP 1.17 ± 1.56; mean in Low BFR group: 1.12 ± 1.20 mg/L