Table 1.
Descriptive Data on Collagen X Biomarker (CXM) and Parameters of Growth and Bone Mineralization, Strength, and Volume
| At 12 months of age | All (n = 256) | Girls (n = 146) | Boys (n = 110) |
|---|---|---|---|
| Mean (SD) | |||
| CXM (ng/mL) [range] | 40.2 (17.4) [1.6–136.6] | 38.7 (13.9) [3.5–92.0] | 42.1 (21.1) [1.6–136.6] |
| PTH (pg/mL) | 26.1 (15.8) | 26.1 (15.4) | 26.1 (16.3) |
| ICa (mmol/L) | 1.33 (0.04) | 1.34 (0.04) | 1.33 (0.03) |
| Length (cm) | 75.0 (2.6) | 74.1 (2.4) | 76.1 (2.4)*** |
| Length (SDS) | −0.64 (1.03) | −0.72 (1.01) | −0.53 (1.05) |
| Weight (kg) | 9.7 (1.1) | 9.3 (0.9) | 10.2 (1.1)*** |
| Weight (SDS) | −0.31 (0.98) | −0.39 (0.95) | −0.20 (1.02) |
| Growth rate in length (SD unit) | −0.01 (0.97) | −0.06 (1.03) | 0.06 (0.89) |
| Length velocity (cm/yr) | 24.7 (2.6) | 24.2 (2.5) | 25.3 (2.5)*** |
| Tibial length (mm) | 137 (7) | 136 (7) | 138 (6)* |
| BMC (mg/mm) | 35.8 (8.2) | 34.1 (8.0) | 38.0 (8.0)*** |
| vBMD (mg/cm3) | 303 (75) | 288 (70) | 322 (77)*** |
| CSA (mm2) | 123 (34) | 123 (34) | 123 (35) |
| PMI (mm4) | 2656 (1675) | 2666 (1626) | 2644 (1745) |
| PsC (mm) | 39.0 (5.2) | 39.0 (5.3) | 39.0 (5.1) |
| At 24 months of age | All (N = 270) | Girls (n = 157) | Boys (n = 113) |
|---|---|---|---|
| CXM (ng/mL) [range] | 38.1 (12.0) [15.7–93.5] | 38.9 (12.9) [15.7–93.51] | 37.1 (10.6) [17.1–73.0] |
| PTH (pg/mL) | 17.7 (8.9) | 18.5 (9.2) | 16.6 (8.5) |
| ICa (mmol/L) | 1.31 (0.04) | 1.32 (0.03) | 1.31 (0.04) |
| Length (cm) | 87.4 (3.2) | 86.6 (3.2) | 88.4 (3.0)*** |
| Length (SDS) | −0.35 (1.08) | −0.40 (1.10) | −0.28 (1.05) |
| Weight (kg) | 12.4 (1.4) | 12.1 (1.3) | 12.8 (1.3)*** |
| Weight (SDS) | −0.25 (1.00) | −0.30 (0.99) | −0.19 (1.01) |
| Growth rate in length (SD unit) | −0.04 (0.97) | 0.07 (1.01) | −0.19 (0.91)* |
| Length velocity (cm/yr) | 12.4 (1.6) | 12.6 (1.7) | 12.1 (1.4)* |
| Tibial length (mm) | 166 (9) | 166 (9) | 167 (9) |
| BMC (mg/mm) | 54.5 (8.2) | 52.8 (7.8) | 57.0 (8.1)*** |
| vBMD (mg/cm3) | 376 (75) | 365 (70) | 392 (79)** |
| CSA (mm2) | 149 (27) | 148 (27) | 149 (27) |
| PMI (mm4) | 3731 (1406) | 3713 (1423) | 3757 (1388) |
| PsC (mm) | 43.0 (3.9) | 43.0 (3.9) | 43.1 (3.9) |
CXM = collagen X biomarker; SDS = standard deviation score (based on Finnish sex‐ and age‐specific norms for child size); BMC = total bone mineral content; vBMD = total volumetric bone mineral density; CSA = total cross‐sectional area; PMI = total polar moment of inertia; PsC = periosteal circumference; PTH = parathyroid hormone; iCa = ionized calcium.
Independent samples t test used to determine statistical significance between sexes, where * indicates p < 0.05, ** indicates p < 0.01, and *** indicates p < 0.001.
Two values missing for the tibial length at 12 months, 10 values missing for PTH at 12 months, 4 values for iCa at 12 months, 24 values missing for iCa at 24 months.