Table 2.
Association between BMI (kg/m²) and total bone mineral density (g/cm2).
| Model 1β (95% CI) P-value | Model 2β (95% CI) P-value | Model 3β (95% CI) P-value | |
|---|---|---|---|
| Body mass index(kg/m²) | 0.014 (0.013, 0.014) <0.001 | 0.006 (0.005, 0.006) <0.001 | 0.005 (0.004, 0.005) <0.001 |
| Subgroup analysis stratified by gender | |||
| Males | 0.015 (0.014, 0.015) <0.001 | 0.005 (0.005, 0.006) <0.001 | 0.005 (0.003, 0.006) <0.001 |
| Females | 0.013 (0.012, 0.014) <0.001 | 0.006 (0.005, 0.006) <0.001 | 0.004 (0.003, 0.006) <0.001 |
| Subgroup analysis stratified by age | |||
| 8–9 years (n = 1,223) | 0.007 (0.006, 0.008) <0.001 | 0.007 (0.006, 0.008) <0.001 | 0.007 (0.006, 0.008) <0.001 |
| 10–11 years (n = 1,180) | 0.007 (0.006, 0.008) <0.001 | 0.007 (0.006, 0.008) <0.001 | 0.007 (0.006, 0.008) <0.001 |
| 12–13 years (n = 944) | 0.007 (0.006, 0.008) <0.001 | 0.006 (0.005, 0.007) <0.001 | 0.006 (0.004, 0.008) <0.001 |
| 14–15 years (n = 959) | 0.007 (0.006, 0.008) <0.001 | 0.007 (0.006, 0.008) <0.001 | 0.006 (0.004, 0.007) <0.001 |
| 16–17 years (n = 961) | 0.004 (0.003, 0.005) <0.001 | 0.004 (0.004, 0.005) <0.001 | 0.004 (0.003, 0.005) <0.001 |
| 18–19 years (n = 876) | 0.004 (0.002, 0.005) <0.001 | 0.003 (0.002, 0.004) <0.001 | 0.004 (0.002, 0.006) <0.001 |
| Subgroup analysis stratified by BMI | |||
| Q1, 18.1< | 0.040 (0.036, 0.044) <0.001 | 0.022 (0.019, 0.025) <0.001 | 0.020 (0.016, 0.024) <0.001 |
| Q2, 18.1-21.0 | 0.032 (0.024, 0.039) <0.001 | 0.014 (0.010, 0.019) <0.001 | 0.014 (0.009, 0.018) <0.001 |
| Q3, 21.1–23.4 | 0.014 (0.008, 0.020) <0.001 | 0.007 (0.004, 0.011) <0.001 | 0.012 (0.004, 0.020) 0.002 |
| Q4, >23.4 | 0.005 (0.004, 0.006) <0.001 | 0.001 (0.000, 0.002) <0.001 | 0.001 (0.001, 0.002) 0.042 |
| P for trend | <0.001 | <0.001 | <0.001 |
Model 1: No covariates were adjusted. Model 2: Age, gender, and race were adjusted. Model 3: Age, gender, race, education level, ratio of family income to poverty, activities status, diabetes status, ALT, ALP, AST, total calcium, total cholesterol, direct HDL cholesterol, LDL cholesterol, triglyceride, phosphorus, blood urea nitrogen, and serum glucose were adjusted. *In the subgroup analysis stratified by gender or race, the model is not adjusted for the stratification variable itself.