Table 4.
Ethnic differences at the tibia using pQCT parameters.
| Mean ± SD |
Group differences (p-values) |
|||||
|---|---|---|---|---|---|---|
| White (n = 216) | Black (n = 42) | South Asian (n = 61) | White vs Black | White vs South Asian | South Asian vs Black | |
| 4% Tibia | ||||||
| Total vBMD (mg/cm3) | ||||||
| Unadjusted | 321.2 ± 43.0 | 334.4 ± 62.7 | 315.4 ± 42.2 | 0.27 | 1.00 | 0.13 |
| Adjusted | 322.8 ± 45.8 | 331.0 ± 45.1 | 312.2 ± 46.8 | 0.86 | 0.40 | 0.12 |
| Trabecular vBMD (mg/cm3) | ||||||
| Unadjusted | 243.8 ± 36.6 | 238.7 ± 49.2 | 226.5 ± 31.8 | 1.00 | 0.006 | 0.33 |
| Adjusted | 244.6 ± 38.2 | 237.1 ± 37.7 | 224.9 ± 39.1 | 0.73 | 0.003 | 0.33 |
| CSA (mm2) | ||||||
| Unadjusted | 1269.7 ± 168.9 | 1198.5 ± 161.4 | 1140.9 ± 128.3 | 0.03 | < 0.0001 | 0.23 |
| Adjusted | 1251.6 ± 143.9 | 1217.9 ± 141.9 | 1192.4 ± 147.2 | 0.50 | 0.02 | 1.00 |
| 38% Tibia | ||||||
| Ct. vBMD (mg/cm3) | ||||||
| Unadjusted | 1172.9 ± 39.0 | 1225.9 ± 20.2 | 1212.6 ± 26.2 | < 0.0001 | < 0.0001 | 0.18 |
| Adjusted | 1173.2 ± 35.4 | 1225.2 ± 34.9 | 1212.1 ± 36.2 | < 0.0001 | < 0.0001 | 0.18 |
| Ct. Thickness (mm) | ||||||
| Unadjusted | 5.9 ± 0.8 | 6.2 ± 0.7 | 5.5 ± 0.6 | 0.03 | 0.007 | < 0.0001 |
| Adjusted | 5.9 ± 0.7 | 6.1 ± 0.7 | 5.5 ± 0.7 | 0.11 | 0.002 | < 0.0001 |
| CSA (mm2) | ||||||
| Unadjusted | 477.1 ± 53.1 | 515.2 ± 58.4 | 452.9 ± 46.5 | < 0.0001 | 0.008 | < 0.0001 |
| Adjusted | 472.4 ± 46.2 | 519.4 ± 45.6 | 469.4 ± 47.3 | < 0.0001 | 1.00 | < 0.0001 |
| Ct. Area (mm2) | ||||||
| Unadjusted | 344.8 ± 44.0 | 376.5 ± 45.1 | 321.1 ± 36.6 | < 0.0001 | 0.001 | < 0.0001 |
| Adjusted | 343.3 ± 39.8 | 376.0 ± 39.2 | 326.7 ± 40.7 | < 0.0001 | 0.019 | < 0.0001 |
| Medullary Area (mm2) | ||||||
| Unadjusted | 132.7 ± 39.8 | 138.7 ± 39.2 | 133.1 ± 32.6 | 1.00 | 1.00 | 1.00 |
| Adjusted | 129.2 ± 37.0 | 143.3 ± 36.5 | 142.5 ± 37.9 | 0.07 | 0.05 | 1.00 |
| CSMI (mm4) | ||||||
| Unadjusted | 16,843.3 ± 3625.3 | 19,735.4 ± 4306.8 | 15,102.9 ± 3020.3 | < 0.0001 | 0.003 | < 0.0001 |
| Adjusted | 16,547.9 ± 3187.6 | 19,936.8 ± 3143.1 | 16,010.1 ± 3259.2 | < 0.0001 | 0.80 | < 0.0001 |
| SSI (mm3) | ||||||
| Unadjusted | 1628.2 ± 466.3 | 1155.8 ± 386.0 | 1140.3 ± 386.0 | < 0.0001 | < 0.0001 | 1.00 |
| Adjusted | 1622.7 ± 394.1 | 1158.5 ± 388.6 | 1157.7 ± 403.0 | < 0.0001 | < 0.0001 | 1.00 |
All values are mean ± SD. Adjusted mean ± SD from a linear regression model with adjustments for age (yr), weight (kg) and height (cm), bold indicates p < 0.05. vBMD, volumetric bone mineral density; CSA, cross-sectional area; Ct, cortical; CSMI, cross-sectional moment of inertia; SSI, stress strain index.