Table 2.
Association between serum Mg and knee chondrocalcinosis in the Xiangya Hospital Health Management Center Study (n = 12,631)
| Tertiles of serum Mg (mmol/L) | P for trend | |||
|---|---|---|---|---|
| 1 (≤0.86) | 2 (0.87–0.91) | 3 (≥0.92) | ||
| Total | ||||
| N for knee* | 9263 | 7438 | 8497 | - |
| Knee chondrocalcinosis (%) | 1.3 | 0.8 | 0.6 | - |
| Model 1 (95% CI) | 1.00 (reference) | 0.59 (0.40, 0.87) | 0.49 (0.33, 0.72) | <0.001 |
| Model 2 (95% CI) | 1.00 (reference) | 0.59 (0.39, 0.89) | 0.53 (0.36, 0.78) | 0.001 |
| Model 3 (95% CI) | 1.00 (reference) | 0.69 (0.36, 1.32) | 0.38 (0.20, 0.71) | 0.002 |
| Model 4 (95% CI) | 1.00 (reference) | 0.60 (0.41, 0.89) | 0.48 (0.33, 0.71) | <0.001 |
| Model 5 (95% CI) | 1.00 (reference) | 0.58 (0.39, 0.88) | 0.52 (0.35, 0.78) | 0.001 |
| Model 6 (95% CI) | 1.00 (reference) | 0.57 (0.38, 0.86) | 0.49 (0.33, 0.73) | <0.001 |
| Model 7 (95% CI) | 1.00 (reference) | 0.60 (0.41, 0.89) | 0.48 (0.33, 0.72) | <0.001 |
| Model 8 (95% CI) | 1.00 (reference) | 0.83 (0.43, 1.58) | 0.46 (0.23, 0.90) | 0.021 |
| Male | ||||
| N for knee* | 5065 | 4279 | 5058 | - |
| Knee chondrocalcinosis (%) | 1.4 | 0.7 | 0.5 | - |
| Model 1 (95% CI) | 1.00 (reference) | 0.56 (0.33, 0.95) | 0.43 (0.25, 0.74) | 0.002 |
| Model 2 (95% CI) | 1.00 (reference) | 0.54 (0.31, 0.96) | 0.45 (0.26, 0.78) | 0.003 |
| Model 3 (95% CI) | 1.00 (reference) | 0.65 (0.27, 1.56) | 0.37 (0.16, 0.84) | 0.017 |
| Model 4 (95% CI) | 1.00 (reference) | 0.57 (0.34, 0.98) | 0.42 (0.24, 0.73) | 0.002 |
| Model 5 (95% CI) | 1.00 (reference) | 0.54 (0.30, 0.94) | 0.45 (0.26, 0.78) | 0.003 |
| Model 6 (95% CI) | 1.00 (reference) | 0.54 (0.31, 0.94) | 0.41 (0.24, 0.72) | 0.001 |
| Model 7 (95% CI) | 1.00 (reference) | 0.57 (0.33, 0.98) | 0.42 (0.24, 0.73) | 0.002 |
| Model 8 (95% CI) | 1.00 (reference) | 0.92 (0.40, 2.11) | 0.51 (0.21, 1.24) | 0.134 |
| Female | ||||
| N for knee* | 4198 | 3159 | 3494 | - |
| Knee chondrocalcinosis (%) | 1.2 | 0.9 | 0.8 | - |
| Model 1 (95% CI) | 1.00 (reference) | 0.64 (0.36, 1.13) | 0.54 (0.30, 0.96) | 0.034 |
| Model 2 (95% CI) | 1.00 (reference) | 0.65 (0.36, 1.19) | 0.60 (0.33, 1.09) | 0.094 |
| Model 3 (95% CI) | 1.00 (reference) | 0.78 (0.29, 2.13) | 0.41 (0.14, 1.21) | 0.091 |
| Model 4 (95% CI) | 1.00 (reference) | 0.65 (0.37, 1.15) | 0.54 (0.31, 0.96) | 0.035 |
| Model 5 (95% CI) | 1.00 (reference) | 0.65 (0.36, 1.18) | 0.59 (0.33, 1.07) | 0.081 |
| Model 6 (95% CI) | 1.00 (reference) | 0.65 (0.35, 1.19) | 0.60 (0.33, 1.10) | 0.096 |
| Model 7 (95% CI) | 1.00 (reference) | 0.65 (0.36, 1.14) | 0.54 (0.30, 0.96) | 0.034 |
| Model 8 (95% CI) | 1.00 (reference) | 0.67 (0.24, 1.88) | 0.37 (0.13, 1.12) | 0.073 |
Model 1 included age (40–49, 50–59, 60–69, ≥70 years), body mass index (BMI) (<25, ≥25 kg/m2) and sex (age and BMI for the sex subgroup) (n = 12,631)
Model 2 added serum iron (tertiles) on the basis of model 1 (n = 12,149)
Model 3 added serum ferritin (tertiles) on the basis of model 1 (n = 5113)
Model 4 added serum calcium (tertiles) on the basis of model 1 (n = 12,479)
Model 5 added serum zinc (tertiles) on the basis of model 1 (n = 12,154)
Model 6 added serum copper (tertiles) on the basis of model 1 (n = 12,153)
Model 7 added serum phosphorus (tertiles) on the basis of model 1 (n = 12490)
Model 8 added education (high school or above, lower than high school) and occupation (manual labor, non-manual labor) on the basis of model 1 (n = 5844)
*Five right knees and four left knees with Kellgren-Lawrence grade 4were excluded from analysis (data from the contralateral knees were retained)
Mg magnesium, N number, CI confidence interval