Table 1.
Baseline and changes over 12 months in clinical characteristics, body composition and biochemical parameters
| Baseline measures | Within group change over 12 months [mean (95% confidence interval)] | P-value comparing changes between groups over 12 months | |||
|---|---|---|---|---|---|
| AN-IGF-1− (n = 37) | AN-IGF-1+ (n = 38) | AN-IGF-1− (n = 21) | AN-IGF-1+ (n = 12) | ||
| Clinical characteristics | |||||
| Age (years) | 19.4 ± 0.4 | 19.4 ± 0.3 | — | — | — |
| Bone age (years) | 18.0 (16.6 to 18.0) | 18.0 (16.3 to 18.0) | — | — | — |
| Height (cm) | 165.9 ± 1.0 | 163.1 ± 0.9a | 0.1 (−0.3, 0.4) | 0.8 (−0.0, 1.5) | 0.061 |
| Race (% white /% African American /% more than 1 race) | 89.2/0.0/10.8 | 89.5/2.6/7.9 | — | — | — |
| Ethnicity (% non-Hispanic/% Hispanic) | 89.2/10.8 | 97.4/2.6 | — | — | — |
| Weight (kg) | 51.4 ± 0.9 | 49.7 ± 0.8 | 3.1 (1.0, 5.1) | 1.7 (−1.5, 4.9) | 0.627 |
| BMI (kg/m2) | 18.7 ± 0.3 | 18.7 ± 0.3 | 1.1 (0.3, 1.9) | 0.5 (−0.8, 1.7) | 0.562 |
| BMI Z-Score | −0.92 (−1.54 to −0.56) | −0.96 (−1.81 to −0.54) | 0.45 (0.07, 0.83) | −0.02 (−0.67, 0.63) | 0.489 |
| % median BMI for age | 87.4 ± 1.4 | 87.2 ± 1.2 | 4.6 (0.8, 8.4) | 1.6 (−4.1, 7.2) | 0.562 |
| Age of menarche (years) | 13.0 (12.0 to 14.0) | 13.0 (12.0 to 14.0) | — | — | — |
| Duration of amenorrhea (months) | 4.00 (0.00 to 11.50) | 3.00 (0.00 to 8.50) | — | — | — |
| Weight-bearing exercise activity (hours per week) | 3.33 (1.52 to 6.47) | 3.65 (1.23 to 6.45) | 0.16 (−4.38, 4.69) | −2.90 (−7.59, 1.80) | 0.669 |
| DXA measures of body composition | |||||
| Lean mass (kg) | 37.5 ± 0.6 | 36.7 ± 0.6 | 1.5 (0.5, 2.5) | 0.6 (−0.5, 1.6) | 0.185 |
| Lean mass (%) | 71.9 ± 0.9 | 72.0 ± 0.8 | −2.0 (−4.3, 0.2) | −0.2 (−3.3, 2.9) | 0.307 |
| Fat mass (kg) | 13.1 ± 0.6 | 12.7 ± 0.5 | 2.0 (0.3, 3.6) | 0.9 (−1.6, 3.4) | 0.464 |
| Fat mass (%) | 24.6 ± 0.9 | 24.6 ± 0.8 | 2.1 (−0.2, 4.5) | 0.2 (−3.1, 3.5) | 0.319 |
| Biochemical parameters | |||||
| 25(OH) vitamin D (ng/mL) | 33.0 (27.5 to 45.3) | 30.5 (24.4 to 39.5) | −6.7 (−12.6, −1.3) | −0.6 (−8.3, 7.0) | 0.082 |
| Calcium (mg/dL) | 9.44 ± 0.05 | 9.42 ± 0.07 | −0.16 (−0.34, 0.03) | 0.19 (−0.24, 0.63) | 0.111 |
| Phosphorus (mg/dL) | 4.09 ± 0.08 | 4.01 ± 0.08 | −0.26 (−0.51, 0.00) | −0.25 (−0.90, 0.39) | 0.878 |
| IGF-1 (ng/mL) | 266.8 ± 14.3 | 249.7 ± 15.3 | −32.9 (−67.4, 1.7) | 101.9 (11.3, 192.5) | 0.004 |
| IGF-1 Z-score | −0.1 (−1.0 to 0.4) | −0.3 (−1.0 to 0.2) | −0.1 (−0.5, 0.3) | 1.1 (0.1, 2.0) | 0.019 |
| IGF-BP3 (ng/mL) | 5073.7 ± 172.3 | 4988.5 ± 172.2 | −517.0 (−625.0, −408.9) | −251.9 (−1045.3, 541.5) | 0.441 |
| IGF-1/IGF-BP3 | 0.054 (0.041 to 0.062) | 0.053 (0.037 to 0.063) | −0.002 (−0.009, 0.006) | 0.030 (0.003, 0.057) | 0.011 |
| P1NP (μg/L) | 86.7 (63.3 to 131.7) | 98.7 (62.5 to 147.5) | −12.1 (−33.4, 9.3) | −39.5 (−89.2, 10.1) | 0.280 |
| NTX (nM BCE) | 14.5 (10.8 to 19.1) | 15.4 (10.5 to 19.8) | −3.5 (−6.8, −0.1) | −1.0 (−7.7, 5.6) | 0.167 |
| PTH (pg/mL) | 21.5 ± 9.2 | 17.4 ± 1.7 | −0.2 (−5.9, 5.4) | 10.6 (2.9, 18.2) | 0.021 |
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.
Abbreviations: BCE, bone collagen equivalents; IGF-1, insulin like growth factor-1, IGFBP-3: insulin like growth factor binding protein 3; NTX: N-telopeptide; P1NP: N-terminal propeptide of type 1 procollagen; PTH: parathyroid hormone
a Denotes significant baseline between-group difference.