Table 2.
Baseline and changes over 12 months in DXA, HRpQCT, and finite element analysis measures
| Baseline measures | Within group change over 12 months [mean (95% confidence interval)] | P-values comparing changes between groups over 12 months | |||||
|---|---|---|---|---|---|---|---|
| AN-IGF-1− | AN-IGF-1+ | AN-IGF-1− | AN-IGF-1+ | Unadjusted | Adjusted for baseline age, height, and bone measure | Adjusted for baseline age, height, bone measure, and 12-month weight change | |
| DXA | n = 36 | n = 37 | n = 21 | n = 12 | |||
| 1/3 radius BMD (g/cm2) | 0.677 ± 0.009 | 0.664 ± 0.007 | 0.004 (−0.003, 0.011) | 0.000 (−0.015, 0.015) | 0.736 | 0.932 | 0.936 |
| 1/3 radius BMD Z-score | −0.133 ± 0.173 | −0.413 ± 0.129 | −0.005 (−0.114, 0.104) | −0.027 (−0.273, 0.219) | 0.276 | 0.772 | 0.810 |
| FN BMD (g/cm2) | 0.757 ± 0.020 | 0.775 ± 0.018 | 0.011 (−0.010, 0.032) | 0.014 (−0.014, 0.041) | 0.849 | 0.420 | 0.396 |
| FN BMD Z-score | −1.24 ± 0.19 | −1.09 ± 0.17 | −0.016 (−0.262, 0.231) | 0.101 (−0.146, 0.347) | 0.470 | 0.350 | 0.278 |
| Total hip BMD (g/cm2) | 0.861 ± 0.019 | 0.882 ± 0.017 | 0.024 (0.007, 0.040) | 0.016 (−0.007, 0.038) | 0.487 | 0.898 | 0.967 |
| Total hip BMD Z-score | −0.786 ± 0.169 | −0.614 ± 0.145 | 0.155 (−0.005, 0.315) | 0.091 (−0.101, 0.282) | 0.555 | 0.790 | 0.914 |
| LS BMD (g/cm2) | 0.862 (0.742 to 0.960) | 0.896 (0.807 to 0.953) | 0.043 (0.025, 0.061) | 0.010 (−0.004, 0.024) | 0.004 | 0.018 | 0.035 |
| LS BMD Z-score | −1.31 ± 0.22 | −1.08 ± 0.17 | 0.280 (0.085, 0.475) | 0.045 (−0.083, 0.174) | 0.028 | 0.064 | 0.109 |
| WB BMD (g/cm2) | 0.998 ± 0.015 | 1.01 ± 0.01 | 0.019 (0.009, 0.030) | 0.008 (−0.007, 0.024) | 0.283 | 0.469 | 0.321 |
| WB BMD Z-score | −1.21 ± 0.19 | −1.16 ± 0.13 | 0.110 (−0.059, 0.279) | 0.009 (−0.170, 0.188) | 0.547 | 0.670 | 0.503 |
| HRpQCT | n = 35 | n = 33 | n = 19 | n = 12 | |||
| Distal radius | |||||||
| Bone geometry | |||||||
| Cort. area (mm2) | 43.0 (36.0 to 50.0) | 43.9 (40.8 to 49.9) | 3.8 (0.9, 6.7) | 2.4 (0.0, 4.8) | 0.401 | 0.965 | 0.861 |
| Trab. area (mm2) | 215.7 (194.8 to 242.7) | 197.2 (170.1 to 223.9)a | −3.7 (−7.9, 0.4) | −1.8 (−4.2, 0.7) | 0.839 | 0.390 | 0.890 |
| Cort. thickness (mm) | 0.650 (0.550 to 0.774) | 0.700 (0.590 to 0.795) | 0.053 (0.011, 0.094) | 0.039 (−0.002, 0.080) | 0.599 | 0.623 | 0.517 |
| Bone microarchitecture | |||||||
| Cort. porosity (%) | (n = 34) 1.13 (0.67 to 1.39) | 1.29 (0.68 to 1.78) | −0.74 (−2.10, 0.62) | 0.00 (−0.20, 0.19) | 0.568 | 0.684 | 0.853 |
| Trab. number (1/mm) | 1.92 ± 0.05 | 1.91 ± 0.05 | −0.02 (−0.12, 0.07) | −0.10 (−0.18, −0.02) | 0.202 | 0.318 | 0.344 |
| Trab. separation (mm) | 0.444 (0.402 to 0.518) | 0.452 (0.413 to 0.493) | 0.005 (−0.020, 0.030) | 0.023 (−0.002, 0.048) | 0.301 | 0.360 | 0.400 |
| Trab. thickness (mm) | 0.067 (0.060 to 0.078) | 0.066 (0.062 to 0.074) | 0.002 (−0.002, 0.005) | 0.002 (−0.007, 0.010) | 0.714 | 0.598 | 0.670 |
| vBMD | |||||||
| Cort. vBMD (mgHA/cm3) | 812.9 (780.9 to 844.8) | 827.4 (789.1 to 859.8) | 26.1 (12.0, 40.1) | 16.9 (5.0, 28.9) | 0.530 | 0.620 | 0.636 |
| Trab. vBMD (mgHA/cm3) | 160.0 ± 6.7 | 155.3 ± 5.2 | 1.5 (−2.3, 5.3) | −5.1 (−23.3, 13.1) | 0.394 | 0.642 | 0.626 |
| Total vBMD (mgHA/cm3) | 284.0 ± 9.0 | 294.1 ± 8.6 | 10.4 (1.4, 19.5) | 5.7 (−16.1, 27.5) | 0.855 | 0.997 | 0.928 |
| Strength estimates | |||||||
| Stiffness (kN/mm) | 65.6 (54.1 to 83.1) | 65.1 (57.1 to 74.2) | 2.3 (−1.2, 5.8) | 0.8 (−3.3, 4.9) | 0.584 | 0.745 | 0.790 |
| Failure load (kN) | 3.58 ± 0.16 | 3.35 ± 0.93 | 0.10 (0.00, 0.24) | 0.03 (−0.12, 0.19) | 0.417 | 0.679 | 0.759 |
| Distal tibia | (n = 36) | (n = 33) | n = 21) | (n = 12) | |||
| Bone geometry | |||||||
| Cort. area (mm2) | 102.7 (90.5 to 119.9) | 102.2 (96.2 to 118.5) | 1.4 (−0.1, 2.9) | 3.1 (−1.1, 7.2) | 0.574 | 0.309 | 0.365 |
| Trab. area (mm2) | 539.1 ± 12.2 | 509.9 ± 14.4 | −0.8 (−2.2, 0.5) | −2.9 (−6.1, 0.2) | 0.203 | 0.371 | 0.890 |
| Cort. thickness (mm) | 1.06 ± 0.03 | 1.09 ± 0.03 | 0.02 (−0.00, 0.03) | 0.04 (−0.01, 0.08) | 0.409 | 0.294 | 0.336 |
| Bone microarchitecture | |||||||
| Cort. porosity (%) | 2.56 (2.05 to 3.14) | 2.51 (1.81 to 3.27) | −0.07 (−0.20, 0.07) | 0.01 (−0.49, 0.51) | 0.750 | 0.778 | 0.738 |
| Trab. number (1/mm) | 1.77 ± 0.04 | 1.82 ± 0.05 | 0.03 (−0.02, 0.08) | −0.04 (−0.17, 0.09) | 0.297 | 0.474 | 0.534 |
| Trab. separation (mm) | 0.474 (0.443 to 0.531) | 0.461 (0.414 to 0.515) | −0.009 (−0.022, 0.005) | 0.005 (−0.037, 0.047) | 0.708 | 0.674 | 0.749 |
| Trab. thickness (mm) | 0.087 ± 0.002 | 0.087 ± 0.003 | −0.002 (−0.004, 0.001) | −0.001 (−0.008, 0.006) | 0.837 | 0.663 | 0.731 |
| vBMD | |||||||
| Cort. vBMD (mgHA/cm3) | 863.2 ± 5.2 | 867.4 ± 5.5 | 10.1 (5.8, 14.4) | 9.0 (2.4, 15.6) | 0.762 | 0.712 | 0.722 |
| Trab. vBMD (mgHA/cm3) | 183.7 ± 5.9 | 186.8 ± 5.8 | 0.1 (−2.9, 3.1) | −4.4 (−13.4, 4.6) | 0.155 | 0.236 | 0.264 |
| Total vBMD (mgHA/cm3) | 297.2 ± 6.8 | 305.8 ± 7.3 | 2.8 (−1.3, 6.9) | 1.9 (−6.9, 10.6) | 0.940 | 0.680 | 0.695 |
| Strength estimates | |||||||
| Stiffness (kN/mm) | 203.0 ± 5.6 | 194.8 ± 5.9 | −1.0 (−4.2, 2.2) | −0.1 (−8.2, 8.1) | 0.812 | 0.774 | 0.827 |
| Failure load k(N) | 10.2 ± 0.3 | 9.8 ± 0.3 | 0.0 (−0.2, 0.1) | 0.0 (−0.3, 0.3) | 0.845 | 0.829 | 0.812 |
Baseline data are presented as mean ± standard error of the mean or median (interquartile range); changes over 12 months are presented as mean (95% confidence interval). Bolded change over 12 months denotes significant within-group difference. Bolded P-value denotes significant between-group difference.
Abbreviations: BMD, bone mineral density; Cort, cortical; DXA, dual energy X-ray absorptiometry; FN, femoral neck; HRpQCT, high resolution peripheral quantitative computed tomography; LS, lumbar spine; Trab, trabecular; vBMD, volumetric bone mineral density; WB, whole body.
a Denotes significant baseline between-group difference.