Table 3.
Basic characteristics of the study population in XO Study I (n = 1316)
| Tertiles of serum Mg (mmol/L) | |||
|---|---|---|---|
| 1 (≤0.89) | 2 (0.90-0.95) | 3 (≥0.96) | |
| Number | 490 | 400 | 426 |
| Median Mg level (mmol/L) | 0.85 | 0.92 | 1.00 |
| Sex (female, %) | 48.6 | 50.3 | 55.2 |
| Age (years) | 63.6 ± 8.9 | 63.3 ± 8.4 | 61.6 ± 8.5 |
| 50–59 (%) | 37.1 | 36.3 | 46.4 |
| 60–69 (%) | 36.3 | 40.0 | 34.9 |
| ≥70 (%) | 26.7 | 23.8 | 18.7 |
| BMI (kg/m2) | 24.1 ± 3.5 | 24.3 ± 3.9 | 24.3 ± 3.4 |
| < 25 (%) | 67.6 | 61.0 | 59.9 |
| ≥25 (%) | 32.4 | 39.0 | 40.1 |
| Knee injury (yes, %) | 5.5 | 3.8 | 5.2 |
| Serum PTH (μmol/L) | 52.5 ± 38.0 | 54.8 ± 23.1 | 51.3 ± 20.2 |
| Serum iron (μmol/L) | 20.2 ± 8.6 | 19.8 ± 7.2 | 20.3 ± 7.8 |
| Serum TIBC (μmol/L) | 58.3 ± 11.3 | 59.1 ± 11.6 | 60.2 ± 11.4 |
| Serum UIBC (μmol/L) | 38.2 ± 13.5 | 39.5 ± 13.2 | 40.0 ± 13.1 |
| Serum calcium (mmol/L) | 2.3 ± 0.1 | 2.3 ± 0.1 | 2.3 ± 0.1 |
| Serum 25(OH)D (μg/L) | 25.8 ± 11.3 | 24.9 ± 9.9 | 25.9 ± 10.9 |
| Serum zinc (μmol/L) | 17.3 ± 3.5 | 18.5 ± 3.7 | 19.9 ± 6.1 |
| Serum copper (μmol/L) | 16.3 ± 3.2 | 16.4 ± 3.7 | 16.8 ± 3.5 |
| Serum phosphorus (mmol/L) | 1.2 ± 0.2 | 1.2 ± 0.2 | 1.2 ± 0.2 |
| Education (educated, %) | 70.2 | 66.5 | 67.8 |
| Occupation (farmer, %) | 85.5 | 87.3 | 85.7 |
Mg magnesium, BMI body mass index, PTH parathyroid hormone, TIBC, total iron binding capacity, UIBC unsaturated iron-binding capacity