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Table 4 Association between Cu/Zn ratio and knee chondrocalcinosis (n = 12,362)

From: Association between serum zinc and copper concentrations and copper/zinc ratio with the prevalence of knee chondrocalcinosis: a cross-sectional study

 

Tertiles of Cu/Zn ratio

P for trend

1 (≤ 1.07)

2 (1.08–1.38)

3 (≥ 1.39)

Total

 Knee chondrocalcinosis (%)

0.7

1.0

2.1

–

 N for kneea

8158

8406

8157

–

 Model 1 (95% CI)

1.00 (reference)

1.02 (0.61, 1.69)

2.23 (1.38, 3.59)

< 0.001

 Model 2 (95% CI)

1.00 (reference)

1.00 (0.60, 1.67)

2.12 (1.31, 3.42)

< 0.001

 Model 3 (95% CI)

1.00 (reference)

1.03 (0.62, 1.72)

2.27 (1.40, 3.68)

< 0.001

 Model 4 (95% CI)

1.00 (reference)

1.03 (0.62, 1.71)

2.26 (1.41, 3.63)

< 0.001

 Model 5 (95% CI)

1.00 (reference)

1.01 (0.61, 1.68)

2.20 (1.36, 3.55)

< 0.001

  1. Model 1 included age (40–49, 50–59, 60–69, ≥ 70 years), body mass index (< 28, ≥ 28 kg/m2) and sex (n = 12,362);
  2. Model 2 added serum iron (tertiles) on the basis of model 1 (n = 12,357);
  3. Model 3 added serum calcium (tertiles) on the basis of model 1 (n = 12,264);
  4. Model 4 added serum magnesium (tertiles) on the basis of model 1 (n = 12,362);
  5. Model 5 added serum phosphorus (tertiles) on the basis of model 1 (n = 12,264)
  6. aThree right knees with K-L 4 grade were excluded for analysis (data from the contralateral knees were retained)
  7. N number, CI confidence interval, Cu/Zn ratio the ratio of serum copper to zinc concentrations