Table 3 Summary of meta-analysis results and subgroups analysis
Groups | Studies | Test of association | Heterogeneity | |||||
|---|---|---|---|---|---|---|---|---|
RR (95% CI) | P value | Model | Z | Chi square | P value | I square | ||
Total studies | 48 | 1.71 (1.11–2.62) | 0.015 | Random | 2.44 | 26,313.92 | < 0.001 | 99.8% |
Subgroup analyses | ||||||||
Study design | ||||||||
 Cohort | 43 | 1.73 (1.10–2.72) | 0.018 | Random | 2.36 | 25,159.19 | < 0.001 | 99.8% |
 Case control | 5 | 1.46 (0.97–2.20) | 0.070 | Random | 1.81 | 28.38 | < 0.001 | 85.9% |
Time Period | ||||||||
 1999–2010 | 18 | 1.64 (1.31–2.05) | < 0.001 | Random | 4.29 | 117.09 | < 0.001 | 85.5% |
 2010–2017 | 30 | 1.74 (0.97–3.09) | 0.062 | Random | 1.87 | 25,671.51 | < 0.001 | 99.9% |
Region | ||||||||
 Asia | 11 | 1.71 (1.53–1.92) | < 0.001 | Random | 9.38 | 17.12 | 0.072 | 41.6% |
 Europe | 26 | 1.74 (0.95–3.21) | 0.075 | Random | 1.78 | 25,090.51 | < 0.001 | 99.9% |
 America | 11 | 1.78 (1.31–2.41) | < 0.001 | Random | 3.70 | 52.30 | < 0.001 | 80.9% |