Table 3.
Subgroup analysis of MetS for the highest vs. lowest dietary copper level category.
| Stratification | Number of studies | Pooled RR | 95% CI | P- value | Heterogeneity |
|---|---|---|---|---|---|
| All studies | 7 | 0.85 | 0.78, 0.93 | P < 0.001 | P = 0.39; I2 = 5% |
| Study design | |||||
| Cross-sectional | 7 | 0.85 | 0.78, 0.93 | P < 0.001 | P = 0.39; I2 = 5% |
| Cohort | / | / | / | / | / |
| Race | |||||
| Asian | 4 | 0.87 | 0.78, 0.97 | P = 0.01 | P = 0.10; I2 = 49% |
| American | 3 | 0.81 | 0.69, 0.95 | P = 0.008 | P = 1.00; I2 = 0% |
| Diagnostic criteria of MetS | |||||
| NCEP ATP III/IDF | 4 | 0.87 | 0.78, 0.97 | P = 0.01 | P = 0.10; I2 = 49% |
| Other | 3 | 0.81 | 0.69, 0.95 | P = 0.008 | P = 1.00; I2 = 0% |
| Sample size | |||||
| <1,000 | 2 | 0.64 | 0.40, 1.02 | P = 0.06 | P = 0.57; I2 = 0% |
| >1,000 | 5 | 0.86 | 0.78, 0.94 | P = 0.001 | P = 0.35; I2 = 10% |
| Exposure assessment | |||||
| FFQ | 1 | 0.81 | 0.70, 0.94 | / | / |
| 24 h or 3 days recall | 6 | 0.87 | 0.78, 0.98 | P = 0.02 | P = 0.35; I2 = 10% |
| Population | |||||
| Adults | 5 | 0.85 | 0.78, 0.93 | P < 0.001 | P = 0.14; I2 = 41% |
| Adolescents | 2 | 0.82 | 0.46, 1.46 | P = 0.50 | P = 0.99; I2 = 0% |