Table 4 . The results of heterogeneity test (I squares) and Estimated OR for related SEFs .
| No | Variable | Practical definition | Number of studies | Model of metaanalyses | Estimated OR | 95% CI of OR | Results of heterogeneity test (I squares) |
| 1 | Sex | Female vs. male | 3 | Random-effect meta-analysis model | 2.06 | 1.45- 2.93 | 88.9%, p=0.00 |
| 2 | Age | 30< vs. ≤30 yo | 4 | Random-effect meta-analysis model | 1.66 | 1.24- 2.22 | 99.2%, p=0.00 |
| 3 | Marital status | Ever married vs. never married | 6 | Random-effect meta-analysis model | 2.14 | 1.36- 3.38 | 97.7%, p=0.00 |
| 4 | Education | High education (more than 12yos) vs. low education | 7 | Random-effect meta-analysis model | 0.60 | 0.43- 0.83 | 92.9%, p=0.00 |
| 5 | Living place | Urban vs. rural residence | 5 | Random-effect meta-analysis model | 1.58 | 1.18- 2.11 93.4%, | p=0.00 |