Table 2.
Multiple Linear Regression Results*: Narrow Neck
| Outcomes and covariates |
Base model |
Model II |
Model III |
|||
| Percent difference (95% CI) | p | Percent difference (95% CI) | p | Percent difference (95% CI) | p | |
| BMD (g/cm2) | ||||||
| Fat mass, 10 kg | −1.0 (−2.6, 0.6) | 0.21 | ||||
| Lean mass, 10 kg | 7.9 (6.0, 9.7) | <0.001 | 8.7 (6.3, 11.0) | <0.001 | ||
| Race/ethnicity, age = 50 yr | <0.001 | <0.001 | <0.001 | |||
| Black | 11.2 (8.5, 13.9) | 9.0 (6.3, 11.7) | 8.6 (5.8, 11.4) | |||
| Hispanic | 5.1 (2.2, 8.1) | 4.8 (2.2, 7.4) | 4.6 (2.0, 7.2) | |||
| White | Ref | Ref | Ref | |||
| Age, 10 yr | <0.001 | <0.001 | <0.001 | |||
| Black | −3.1 (−4.9, −1.2) | −2.7 (−4.3, −1.0) | −2.5 (−4.2, −0.9) | |||
| Hispanic | −5.1 (−6.5, −3.7) | −4.5 (−5.9, −3.1) | −4.4 (−5.8, −3.0) | |||
| White | −2.1 (−3.5, −0.8) | −1.7 (−2.9, −0.4) | −1.6 (−2.8, −0.3) | |||
| Height (cm) | 0.4 (0.2, 0.6) | <0.001 | −0.04 (−0.2, 0.1) | 0.63 | −0.1 (−0.2, 0.1) | 0.47 |
| PASE, 100 units | 1.7 (0.7, 2.8) | 0.002 | 1.6 (0.5, 2.6) | 0.003 | 1.4 (0.4, 2.5) | 0.01 |
| CSA (cm2) | ||||||
| Fat mass, 10 kg | −2.7 (−4.2, −1.1) | 0.001 | ||||
| Lean mass, 10 kg | 10.2 (8.2, 12.3) | <0.001 | 12.2 (9.8, 14.7) | <0.001 | ||
| Race/ethnicity, age = 50 yr | <0.001 | <0.001 | 0.001 | |||
| Black | 8.5 (5.8, 11.2) | 6.0 (3.4, 8.5) | 5.0 (2.3, 7.6) | |||
| Hispanic | 2.5 (0.5, 5.5) | 2.1 (−0.4, 4.5) | 1.5 (−0.9, 4.0) | |||
| White | Ref | ref | Ref | |||
| Age, 10 yr | <0.001 | <0.001 | <0.001 | |||
| Black | −2.4 (−4.2, −0.6) | −1.8 (−3.2, −0.3) | −1.4 (−2.8, 0.1) | |||
| Hispanic | −4.3 (−5.7, −2.8) | −3.5 (−4.8, −2.3) | −3.3 (−4.6, −2.0) | |||
| White | −1.9 (−3.4, −0.5) | −1.3 (−2.6, −0.03) | −1.0 (−2.3, 0.2) | |||
| Height (cm) | 0.8 (0.6, 1.0) | <0.001 | 0.2 (−0.003, 0.4) | 0.05 | 0.1 (−0.1, 0.3) | 0.18 |
| PASE, 100 units | 1.4 (0.2, 2.6) | 0.02 | 1.2 (0.1, 2.3) | 0.04 | 0.9 (−0.2, 2.0) | 0.13 |
| Z (cm3) | ||||||
| Fat mass, 10 kg | −4.6 (−6.6, −2.6) | <0.001 | ||||
| Lean mass, 10 kg | 11.4 (8.8, 14.0) | <0.001 | 14.9 (11.7, 18.1) | <0.001 | ||
| Race/ethnicity, age = 50 yr | 0.001 | 0.07 | 0.29 | |||
| Black | 6.3 (2.8, 9.8) | 3.6 (0.2, 6.9) | 1.8 (−1.6, 5.3) | |||
| Hispanic | 0.6 (−3.0, 4.2) | 0.1 (−3.0, 3.3) | −0.8 (−3.9, 2.3) | |||
| White | Ref | ref | ref | |||
| Age, 10 yr | 0.02 | 0.06 | 0.19 | |||
| Black | −1.6 (−3.7, 0.5) | −0.8 (−2.6, 0.9) | −0.2 (−1.9, 1.6) | |||
| Hispanic | −3.2 (−5.5, −1.0) | −2.4 (−4.2, −0.7) | −2.0 (−3.8, −0.2) | |||
| White | −0.7 (−2.5, 1.2) | 0.02 (−1.7, 1.7) | 0.5 (−1.2, 2.2) | |||
| Height (cm) | 1.1 (0.9, 1.4) | <0.001 | 0.5 (0.2, 0.8) | <0.001 | 0.4 (0.1, 0.7) | 0.01 |
| PASE, 100 units | 1.6 (−0.1, 3.4) | 0.07 | 1.4 (−0.3, 3.1) | 0.10 | 0.9 (−0.8, 2.6) | 0.31 |
| ABR | ||||||
| Fat mass, 10 kg | −1.3 (−3.6, 1.0) | 0.26 | ||||
| Lean mass, 10 kg | −6.1 (−8.7, −3.5) | <0.001 | −5.1 (−8.6, −1.6) | 0.005 | ||
| Race/ethnicity, age = 50 yr | <0.001 | <0.001 | <0.001 | |||
| Black | −15.0 (−19.0, −11.1) | −13.1 (−17.2, −9.1) | −13.6 (−17.8, −9.4) | |||
| Hispanic | −10.3 (−14.6, −6.1) | −10.2 (−14.3, −6.1) | −10.4 (−14.6, −6.3) | |||
| White | Ref | ref | ref | |||
| Age, 10 yr | <0.001 | <0.001 | <0.001 | |||
| Black | 4.3 (2.4, 6.1) | 4.0 (2.1, 5.9) | 4.2 (2.3, 6.1) | |||
| Hispanic | 6.0 (3.9, 8.0) | 5.5 (3.4, 7.5) | 5.6 (3.5, 7.7) | |||
| White | 3.7 (1.6, 5.7) | 3.3 (1.2, 5.4) | 3.5 (1.4, 5.6) | |||
| Height (cm) | 0.004 (−0.2, 0.2) | 0.97 | 0.3 (0.1, 0.6) | 0.02 | 0.3 (0.02, 0.6) | 0.04 |
| PASE, 100 units | −2.5 (−3.9, −1.0) | 0.001 | −2.3 (−3.8, −0.9) | 0.002 | −2.5 (−4.0, −1.0) | 0.001 |
*Point estimates and CIs reflect percentage differences in indices of bone strength. Percentages are derived by dividing regression effects by the global mean of the relevant parameters, as in Fig. 2. Models allow both geometry parameters and their cross-sectional age trends to differ by race/ethnicity. Moving from left to right, changes in the magnitude and significance of effects reflect the impact of controlling for lean (model II), and for fat and lean (model III), mass in successive models.