Table 2.
β-Coefficients and SD for Mixed Effects Models Predicting TBLH BMC-Velocity and Lumbar Spine aBMD Velocity Using HT and HT-Velocity, With Corresponding Equations for Calculating Predicted Annualized BMD/aBMD-Vel-Z –Score
| Model 1: HT & HT-Vel-adjusted | ||||
|---|---|---|---|---|
| Female |
Male |
|||
| TBLH BMC-Vel-Z | Tanner stage 1–2 | Tanner stage 3–5 | Tanner stage 1–2 | Tanner stage 3–5 |
| Age at beginning of interval | 12.1 | 7.8 | 8.0** | 76.1*** |
| (Age at beginning of interval)2 | −0.9 | −0.6 | −0.6 | −2.9 |
| TBLH-BMC at beginning of interval | 0.12*** | −0.02*** | 0.14*** | 0.01 |
| HT at beginning of interval | 0.22 | 3.6*** | 0.17 | 3.4*** |
| HV-Vel (cm/year) | 7.1*** | 21.4*** | 10.5*** | 28.4*** |
| Constant | −104** | −472.1*** | −110.7*** | −1,006*** |
| SD | 25.69 | 53.32 | 30.1 | 76.11 |
| Prediction equations: | ||||
| Females Tanner stage 1–2: [TBLH-BMC-Vel – ((12.1*age0) + (−0.9*age02) + (0.1*TBLH-BMC0) + (0.2*Ht0) + (7.1*Ht-Vel) − 104)]/26 Females Tanner stage 3–5: [TBLH-BMC-Vel – ((7.8*age0) + (−0.6*age02) + (−0.02*TBLH-BMC0) + (3.6*Ht0) + (21.4* Ht-Vel) − 472)]/53.3 Males Tanner stage 1–2: [TBLH-BMC-Vel – ((8.0*age0) + (−0.6*age02) + (0.1*TBLH-BMC0) + (0.2*Ht0) + (10.5*Ht-Vel) − 111)]/30.1 Males Tanner stage 3–5: [TBLH-BMC-Vel – ((76.1*age0) + (−2.9*age02) + (0.01*TBLH-BMC0) + (3.4*Ht0) + (28.4*Ht-Vel) – 1006)]/76.1 | ||||
| Female |
Male |
|||
| LS aBMD-Vel-Z | Tanner stage 1–2 | Tanner stage 3–5 | Tanner stage 1–3 | Tanner stage 4–5 |
| Age at beginning of interval | −0.0105* | 0.0087*** | −0.0127*** | 0.0315*** |
| (Age at beginning of interval)2 | 0.0007* | −0.0004*** | 0.0007*** | −0.0012*** |
| LSaBMD at beginning of interval | 0.0119 | −0.0093 | 0.0154 | 0.0085 |
| HT at beginning of interval | 0.0002 | 0.0011*** | 0.0004*** | 0.0007*** |
| HV-Vel (cm/year) | 0.0035*** | 0.0089*** | 0.0046*** | 0.0075*** |
| Constant | 0.0118 | −0.1770*** | −0.0057 | −0.3052*** |
| SD | 0.0212 | 0.0304 | 0.0214 | 0.0328 |
| Prediction equations: | ||||
| Females Tanner stage 1–2: [LSaBMD-Vel – ((−0.0105*age0) + (0.0007*age02) + (0.0119*LSABMD0) + (0.0002*Ht0) + (0.0035*Ht-Vel) + 0.0118)]/ 0.0212 Females Tanner stage 3–5: [LSaBMD-Vel – ((0.0087*age0) + (−0.0004*age2) + (−0.0093*LSaBMD0) + (0.0011*Ht0) + (0.0089*Ht-Vel) −0.177)]/0.0304 Males Tanner stage 1–3: [LSaBMD-Vel – ((−0.0127*age0) + (0.0007*age02) + (0.01544*LSaBMD0) + (0.0004*Ht0) + (0.0046*Ht-Vel) −0.0057)]/0.0214 Males Tanner stage 4–5: [LSaBMD-Vel – ((0.0315*age0) + (−0.0012*age02) + (0.0085*LSaBMD0) + (0.0007*Ht0) + (0.0075*Ht-Vel) −0.3052)]/0.0328 | ||||
aBMD = areal bone mineral density; BMC = bone mineral content; HT = height; HV = height velocity; LS = lumbar spine; TBLH = total body less head; Vel = velocity; Wt = weight.
*
p < 0.1
**
p < 0.05
***
p < 0.01.