Table 2 Univariate and multivariate meta-regression analyses of potential source of heterogeneity

−0.078

0.114

−0.68

0.501

−0.313

0.157

0.189

0.068

2.78

0.016

0.042

0.335

−0.126

0.108

−1.17

0.529

−0.349

0.097

0.125

0.074

1.68

0.336

−0.040

0.290

−0.583

1.407

−0.41

0.682

−3.474

2.308

0.451

1.165

0.39

0.705

−2.067

2.968

−0.574

1.294

−0.44

0.983

−3.252

2.103

0.050

0.936

0.05

1.000

−2.035

2.136

−0.801

0.311

−2.58

0.016

−1.439

−0.163

−0.219

0.223

−0.98

0.344

−0.702

0.263

−0.896

0.327

−2.74

0.016

−1.571

−0.220

−0.086

0.178

−0.48

0.964

−0.483

0.312

0.647

0.866

0.75

0.462

−1.133

2.427

1.408

0.442

3.18

0.007

−0.452

2.364

0.649

0.792

0.82

0.807

−0.990

2.287

0.970

0.534

1.82

0.265

−0.220

2.161