Table 2 Subgroup analysis
Group | Number of studies | Pooled RR | 95% CI | P (heterogeneity) | I2 (%) |
|---|---|---|---|---|---|
All studies | 22 | 2.02 | 1.59-2.57 | 0.000 | 86.3% |
Location | |||||
 America | 8 | 1.44 | 1.16-1.78 | 0.000 | 81.1% |
 Asia | 9 | 2.93 | 1.52-5.65 | 0.000 | 90.7% |
 Europe | 5 | 2.44 | 1.01-5.86 | 0.0033 | 61.8% |
Gender | |||||
 Female | 3 | 1.64 | 1.20-2.25 | 0.117 | 53.4% |
 Male | 4 | 1.18 | 0.96-1.44 | 0.026 | 67.6% |
Exposure | |||||
 CAL | 10 | 2.66 | 1.80-3.94 | 0.000 | 82.5% |
 Others | 12 | 1.65 | 1.20-2.27 | 0.000 | 87.3% |
Study quality | |||||
 High | 12 | 2.29 | 1.61-3.25 | 0.000 | 91.0% |
 Low and moderate | 10 | 1.66 | 1.20-2.29 | 0.001 | 66.5% |
Number of participants | |||||
  > 1000 | 9 | 1.46 | 1.16-1.83 | 0.000 | 76.8% |
  < 1000 | 13 | 2.69 | 1.68-4.30 | 0.000 | 88.3% |