Table 4.
Association between serum Mg and knee chondrocalcinosis of study population in the XO Study I (n = 1316)
| Tertiles of serum Mg (mmol/L) | P for trend | |||
|---|---|---|---|---|
| 1 (≤0.89) | 2 (0.90–0.95) | 3 (≥0.96) | ||
| Total | ||||
| N for knee* | 977 | 793 | 848 | - |
| Knee chondrocalcinosis (%) | 4.8 | 3.2 | 2.0 | - |
| Model 1 (95% CI) | 1.00 (reference) | 0.67 (0.34, 1.30) | 0.45 (0.21, 0.94) | 0.030 |
| Model 2 (95% CI) | 1.00 (reference) | 0.68 (0.35, 1.32) | 0.45 (0.22, 0.94) | 0.046 |
| Model 3 (95% CI) | 1.00 (reference) | 0.73 (0.37, 1.47) | 0.41 (0.18, 0.93) | 0.028 |
| Model 4 (95% CI) | 1.00 (reference) | 0.71 (0.35, 1.41) | 0.41 (0.18, 0.91) | 0.025 |
| Model 5 (95% CI) | 1.00 (reference) | 0.73 (0.37, 1.46) | 0.42 (0.19, 0.94) | 0.032 |
| Model 6 (95% CI) | 1.00 (reference) | 0.71 (0.36, 1.41) | 0.40 (0.18, 0.91) | 0.024 |
| Model 7 (95% CI) | 1.00 (reference) | 0.67 (0.34, 1.30) | 0.45 (0.21, 0.94) | 0.030 |
| Model 8 (95% CI) | 1.00 (reference) | 0.69 (0.35, 1.34) | 0.45 (0.21, 0.95) | 0.032 |
| Model 9 (95% CI) | 1.00 (reference) | 0.71 (0.36, 1.42) | 0.43 (0.20, 0.95) | 0.020 |
| Model 10 (95% CI) | 1.00 (reference) | 0.68 (0.35, 1.33) | 0.41 (0.19, 0.88) | 0.034 |
| Model 11 (95% CI) | 1.00 (reference) | 0.68 (0.35, 1.32) | 0.45 (0.21, 0.95) | 0.033 |
| Model 12 (95% CI) | 1.00 (reference) | 0.65 (0.33, 1.28) | 0.46 (0.21, 0.96) | 0.036 |
| Male | ||||
| N for knee* | 502 | 397 | 380 | - |
| Knee chondrocalcinosis (%) | 3.8 | 2.5 | 1.1 | - |
| Model 1 (95% CI) | 1.00 (reference) | 0.72 (0.26, 2.01) | 0.34 (0.08, 1.37) | 0.115 |
| Model 2 (95% CI) | 1.00 (reference) | 0.75 (0.28, 2.05) | 0.34 (0.08, 1.38) | 0.114 |
| Model 3 (95% CI) | 1.00 (reference) | 0.81 (0.29, 2.30) | 0.39 (0.09, 1.66) | 0.195 |
| Model 4 (95% CI) | 1.00 (reference) | 0.78 (0.28, 2.21) | 0.39 (0.09, 1.62) | 0.184 |
| Model 5 (95% CI) | 1.00 (reference) | 0.87 (0.31, 2.48) | 0.40 (0.10, 1.64) | 0.198 |
| Model 6 (95% CI) | 1.00 (reference) | 0.84 (0.30, 2.35) | 0.39 (0.09, 1.60) | 0.183 |
| Model 7 (95% CI) | 1.00 (reference) | 0.72 (0.26, 2.00) | 0.34 (0.09, 1.37) | 0.117 |
| Model 8 (95% CI) | 1.00 (reference) | 0.65 (0.19, 2.25) | 0.47 (0.11, 1.88) | 0.254 |
| Model 9 (95% CI) | 1.00 (reference) | 0.81 (0.27, 2.42) | 0.21 (0.04, 1.08) | 0.077 |
| Model 10 (95% CI) | 1.00 (reference) | 0.72 (0.26, 2.00) | 0.17 (0.04, 0.83) | 0.024 |
| Model 11 (95% CI) | 1.00 (reference) | 0.63 (0.23, 1.74) | 0.32 (0.08, 1.32) | 0.094 |
| Model 12 (95% CI) | 1.00 (reference) | 0.67 (0.24, 1.93) | 0.34 (0.08, 1.38) | 0.116 |
| Female | ||||
| N for knee* | 475 | 396 | 468 | - |
| Knee chondrocalcinosis (%) | 5.9 | 3.8 | 2.8 | - |
| Model 1 (95% CI) | 1.00 (reference) | 0.64 (0.27, 1.52) | 0.50 (0.20, 1.23) | 0.128 |
| Model 2 (95% CI) | 1.00 (reference) | 0.65 (0.27, 1.55) | 0.50 (0.20, 1.24) | 0.130 |
| Model 3 (95% CI) | 1.00 (reference) | 0.66 (0.27, 1.65) | 0.40 (0.15, 1.10) | 0.069 |
| Model 4 (95% CI) | 1.00 (reference) | 0.62 (0.25, 1.54) | 0.40 (0.14, 1.09) | 0.067 |
| Model 5 (95% CI) | 1.00 (reference) | 0.66 (0.26, 1.63) | 0.42 (0.15, 1.17) | 0.090 |
| Model 6 (95% CI) | 1.00 (reference) | 0.63 (0.25, 1.58) | 0.41 (0.15, 1.10) | 0.071 |
| Model 7 (95% CI) | 1.00 (reference) | 0.64 (0.27, 1.53) | 0.50 (0.20, 1.23) | 0.126 |
| Model 8 (95% CI) | 1.00 (reference) | 0.66 (0.27, 1.59) | 0.50 (0.20, 1.23) | 0.129 |
| Model 9 (95% CI) | 1.00 (reference) | 0.66 (0.27, 1.59) | 0.53 (0.21, 1.33) | 0.174 |
| Model 10 (95% CI) | 1.00 (reference) | 0.66 (0.27, 1.60) | 0.53 (0.21, 1.32) | 0.171 |
| Model 11 (95% CI) | 1.00 (reference) | 0.68 (0.29, 1.64) | 0.52 (0.21, 1.28) | 0.149 |
| Model 12 (95% CI) | 1.00 (reference) | 0.63 (0.26, 1.50) | 0.48 (0.19, 1.21) | 0.116 |
Model 1 included age (50–59, 60–69, ≥70 years), body mass index (BMI) (<25, ≥25 kg/m2) and sex (age and BMI for the sex subgroup) (n = 1316)
Model 2 added knee injury on the basis of model 1 (n = 1316)
Model 3 added serum parathyroid hormone (tertiles) on the basis of model 1 (n = 1250)
Model 4 added serum iron (tertiles) on the basis of model 1 (n = 1250)
Model 5 added serum total iron binding capacity (tertiles) on the basis of model 1 (n = 1241)
Model 6 added serum unsaturated iron binding capacity (tertiles) on the basis of model 1 (n = 1241)
Model 7 added serum calcium (tertiles) on the basis of model 1 (n = 1316)
Model 8 added serum 25(OH)D (tertiles) on the basis of model 1 (n = 1306)
Model 9 added serum zinc (tertiles) on the basis of model 1 (n = 1292)
Model 10 added serum copper (tertiles) on the basis of model 1 (n = 1292)
Model 11 added serum phosphorus (tertiles) on the basis of model 1 (n = 1316)
Model 12 added education (educated, non-educated) and occupation (farmer, non-farmer) on the basis of model 1 (n = 1316)
*Six right knees and eight left knees with Kellgren-Lawrence grade 4 were excluded from analysis (data from the contralateral knees were retained)
Mg magnesium, CI confidence interval