Table 2.
Univariate assessment for low BMD (Z-score ≤ −2 and Z-score ≤ −1) in patients with scoliosis.
| Z-Score ≤ −2 (n = 65) |
Z-Score > −2 (n = 733) |
p-Value * | Z-Score ≤ −1 (n = 299) |
Z-Score > −1 (n = 499) |
p-Value # | |
|---|---|---|---|---|---|---|
| Baseline characteristics | ||||||
| Age, y | 14.7 ± 1.3 | 13.9 ± 1.6 | 0.001 | 14.2 ± 1.6 | 13.9 ± 1.6 | 0.015 |
| Boy, n | 31 (22.1%) | 109 (77.9%) | <0.001 | 83 (59.3%) | 57 (40.7%) | <0.001 |
| Girls, n | 34 (5.2%) | 624 (94.8%) | 216 (32.8%) | 442 (67.2%) | ||
| BMI, kg/m2 | 16.7 ± 2.3 | 18.4 ± 2.9 | <0.001 | 17.3 ± 2.5 | 18.8 ± 2.9 | <0.001 |
| BMI Z-score | −1.6 ± 1.3 | −0.6 ± 1.1 | <0.001 | −1.1 ± 1.2 | −0.36 ± 1.1 | <0.001 |
| Cobb angle | 54.2 ± 12.8 | 53.7 ± 11.2 | 0.99 | 54.9 ± 12.2 | 53.1 ± 10.7 | 0.04 |
| Femoral neck BMD, g/cm2 | 0.66 ± 0.06 | 0.83 ± 0.11 | <0.001 | 0.72 ± 0.07 | 0.88 ± 0.10 | <0.001 |
| Femoral neck BMD Z-score | −2.4 ± 0.4 | −0.5 ± 0.8 | <0.001 | −1.6 ± 0.5 | −0.1 ± 0.7 | <0.001 |
| Laboratory values | ||||||
| Total calcium, mmol/L | 2.47 ± 0.14 | 2.43 ± 0.12 | 0.051 | 2.44 ± 0.13 | 2.43 ± 0.12 | 0.32 |
| Phosphorous, mmol/L | 1.46 ± 0.14 | 1.47 ± 0.16 | 0.50 | 1.49 ± 0.16 | 1.47 ± 0.16 | 0.020 |
| Potassium, mmol/L | 4.05 ± 0.28 | 4.12 ± 0.28 | 0.11 | 4.08 ± 0.27 | 4.13 ± 0.28 | 0.023 |
| Alkaline phosphatase, U/L | 172.8 ± 58.6 | 148.3 ± 72.9 | 0.027 | 170.5 ± 77.5 | 137.5 ± 65.2 | <0.001 |
| Albumin, g/L | 43.1 ± 2.8 | 42.4 ± 2.6 | 0.10 | 42.6 ± 2.9 | 42.4 ± 2.3 | 0.33 |
| Total cholesterol, mmol/L | 3. 51 ± 0.71 | 3.65 ± 0.67 | 0.16 | 3.60 ± 0.64 | 3.67 ± 0.69 | 0.27 |
| Triglyceride, mmol/L | 0.75 ± 0.21 | 0.82 ± 0.38 | 0.05 | 0.81 ± 0.30 | 0.81 ± 0.40 | 0.95 |
| Total bilirubin, umol/L | 11.91 ± 6.34 | 9.29 ± 4.56 | 0.009 | 10.2 ± 5.1 | 9.1 ± 4.6 | 0.007 |
| Creatinine, umol/L | 51.5 ± 13.4 | 47.5 ± 9.6 | 0.056 | 47.8 ± 11.0 | 47.9 ± 9.3 | 0.92 |
| Total bile acid, umol/L | 4.65 ± 3.61 | 4.70 ± 3.69 | 0.93 | 4.9 ± 4.1 | 4.6 ± 3.4 | 0.31 |
p-value * indicates the p-value of the comparison between the groups with and without BMD Z-scores of ≤−2. p-value # indicates the p-value of the comparison between the groups with and without BMD Z-scores of ≤−1. The continuous variables were presented as mean ± standard deviation (SD), and categorical variables were presented as counts (percentages). BMI, body mass index; BMD, bone mineral density. Age, BMI, BMD, and laboratory values were compared by Student’s t-test; Cobb angle was compared by Mann–Whitney U test. Sex was compared by chi-squared test.