Table 1. Characteristics of included studies selected for meta-analysis.
| Study | Year | Country | Ethnicity | Age, mean ± SD, year |
Body mass index (kg/m2) |
Type of study | Sample size |
Control source | Genotype distributions in cases/controls |
Genotyping method | Quality score | HWE* | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Case | Control | Case | Control | Case | Control | 11 | 12 | 22 | |||||||||
| rs2241766 | |||||||||||||||||
| Machado GH | 2014 | Brazil | Caucasian | 26 ± 4.5 | 24 ± 4 | 27.53 ± 5.15 | 22.80 ± 2.7 | Case-control | 113 | 169 | HB | 81/139 | 29/29 | 3/1 | PCR | 8 | 0.697 |
| Machado PE | 2014 | Brazil | Caucasian | 27 ± 4.5 | 24 ± 5 | 26.28 ± 4.8 | 22.80 ± 2.7 | Case-control | 127 | 169 | HB | 97/139 | 26/29 | 4/1 | PCR | 8 | 0.697 |
| Jiang HT | 2014 | China | Mongolian | 68.8 ± 6.7 | 67.1 ± 7.1 | 24.5 ± 4.3 | 23.1 ± 3.3 | Case-control | 202 | 166 | PB | 102/91 | 86/65 | 14/10 | PCR | 10 | 0.720 |
| Jiang HT + DM | 2014 | China | Mongolian | 68.2 ± 6.1 | 67.1 ± 7.2 | 26.0 ± 3.7 | 23.1 ± 3.3 | Case-control | 169 | 166 | PB | 90/91 | 67/65 | 12/10 | PCR | 10 | 0.720 |
| Kang | 2013 | China | Mongolian | NA | NA | 22.57 ± 2.27 | 21.53 ± 2.17 | Case-control | 153 | 126 | HB | 63/75 | 68/40 | 22/11 | PCR | 8 | 0.105 |
| Leu HT | 2011 | China | Mongolian | 41.4 ± 0.7 | 46.7 ± 0.8 | 25.4 ± 0.3 | 23.5 ± 0.1 | Family-based | 159 | 446 | PB | 74/233 | 70/181 | 15/32 | PCR | 10 | 0.696 |
| Leu HT + Mets | 2011 | China | Mongolian | 41.7 ± 0.6 | 57.5 ± 1.0 | 28.3 ± 0.3 | 27.1 ± 0.3 | Family-based | 192 | 165 | PB | 92/78 | 81/75 | 19/12 | PCR | 9 | 0.696 |
| Youpeng | 2010 | China | Mongolian | 30.9 ± 6.0 | 30.0 ± 4.5 | 22.05 ± 2.65 | 20.1 ± 1.8 | Case-control | 107 | 81 | HB | 74/53 | 26/27 | 7/1 | PCR | 7 | 0.228 |
| Wang | 2008 | China | Mongolian | 46.4 ± 14.0 | 46.8 ± 15.4 | 26.82 ± 2.44 | 22.43 ± 3.99 | Case-control | 80 | 160 | HB | 41/87 | 34/60 | 5/13 | PCR | 8 | 0.561 |
| Tang | 2008 | China | Mongolian | 63.5 ± 6.5 | 60.5 ± 7.1 | NA | NA | Case-control | 151 | 100 | HB | 99/63 | 32/28 | 20/9 | PCR | 8 | 0.036 |
| Jeng | 2007 | China | Mongolian | 51.6 ± 14.7 | 50.7 ± 12.1 | 25.7 ± 3.6 | 23.8 ± 3.4 | Case-control | 212 | 356 | HB | 82/126 | 99/173 | 31/57 | PCR | 9 | 0.853 |
| Yan | 2006 | China | Mongolian | 49 ± 9 | 48 ± 10 | 30.8 ± 2.5 | 22.4 ± 1.8 | Case-control | 482 | 497 | HB | 201/222 | 186/203 | 95/72 | PCR | 9 | 0.024 |
| rs1501299 | |||||||||||||||||
| Machado GH | 2014 | Brazil | Caucasian | 26 ± 4.5 | 24 ± 4 | 27.53 ± 5.15 | 22.80 ± 2.7 | Case-control | 113 | 161 | HB | 59/68 | 46/74 | 8/19 | PCR | 8 | 0.868 |
| Machado PE | 2014 | Brazil | Caucasian | 27 ± 4.5 | 24 ± 5 | 26.28 ± 4.8 | 22.80 ± 2.7 | Case-control | 127 | 161 | HB | 66/68 | 47/74 | 14/19 | PCR | 8 | 0.868 |
| Kang | 2013 | China | Mongolian | NA | NA | 22.57 ± 2.27 | 21.53 ± 2.17 | Case-control | 153 | 126 | HB | 100/82 | 46/38 | 7/6 | PCR | 8 | 0.560 |
| Leu HT | 2011 | China | Mongolian | 41.4 ± 0.7 | 46.7 ± 0.8 | 25.4 ± 0.3 | 23.5 ± 0.1 | Family-based | 159 | 446 | PB | 85/228 | 60/178 | 14/40 | PCR | 9 | 0.536 |
| Leu HT + Mets | 2011 | China | Mongolian | 41.7 ± 0.6 | 57.5 ± 1.0 | 28.3 ± 0.3 | 27.1 ± 0.3 | Family-based | 192 | 165 | PB | 117/93 | 68/56 | 7/16 | PCR | 9 | 0.089 |
| Youpeng | 2010 | China | Mongolian | 30.9 ± 6.0 | 30.0 ± 4.5 | 22.05 ± 2.65 | 20.1 ± 1.8 | Case-control | 107 | 81 | HB | 19/19 | 60/49 | 28/13 | PCR | 7 | 0.051 |
| Wang | 2008 | China | Mongolian | 46.4 ± 14.0 | 46.8 ± 15.4 | 26.82 ± 2.44 | 22.43 ± 3.99 | Case-control | 80 | 160 | HB | 41/74 | 28/73 | 11/13 | PCR | 8 | 0.392 |
| Yan | 2006 | China | Mongolian | 49 ± 9 | 48 ± 10 | 30.8 ± 2.5 | 22.4 ± 1.8 | Case-control | 482 | 497 | HB | 259/274 | 184/187 | 39/36 | PCR | 9 | 0.599 |
| Iwashima | 2004 | Japan | Mongolian | 59.4 ± 0.5 | 57.1 ± 0.6 | 24.4 ± 0.1 | 23.1 ± 0.2 | Case-control | 446 | 312 | HB | 225/165 | 180/124 | 41/23 | PCR | 9 | 0.964 |
| rs266729 | |||||||||||||||||
| Machado GH | 2014 | Brazil | Caucasian | 26 ± 4.5 | 24 ± 4 | 27.53 ± 5.15 | 22.80 ± 2.7 | Case-control | 113 | 161 | HB | 61/93 | 36/57 | 16/11 | PCR | 8 | 0.577 |
| Machado PE | 2014 | Brazil | Caucasian | 27 ± 4.5 | 24 ± 5 | 26.28 ± 4.8 | 22.80 ± 2.7 | Case-control | 127 | 161 | HB | 81/93 | 27/57 | 19/11 | PCR | 8 | 0.577 |
| Leu HT | 2011 | China | Mongolian | 41.4 ± 0.7 | 46.7 ± 0.8 | 25.4 ± 0.3 | 23.5 ± 0.1 | Family-based | 198 | 159 | PB | 85/84 | 90/64 | 23/11 | PCR | 9 | 0.800 |
| Leu HT + Mets | 2011 | China | Mongolian | 41.7 ± 0.6 | 57.5 ± 1.0 | 28.3 ± 0.3 | 27.1 ± 0.3 | Family-based | 173 | 159 | PB | 93/84 | 68/64 | 12/11 | PCR | 9 | 0.800 |
| Zhang | 2010 | China | Mongolian | 52.39 ± 9.60 | 49.25 ± 10.84 | NA | NA | Case-control | 220 | 268 | HB | 138/163 | 70/84 | 12/21 | PCR | 8 | 0.035 |
For rs2241766 variant, 11, 12 and 22 represent TT, GT, GG, respectively; for rs1501299 variant, 11, 12 and 22 represent GG, TG and TT, respectively; for rs266729 variant, 11, 12 and 22 represent CC, CG, and GG.
GH = gestational hypertension; PE = pre-eclampsia; HT = hypertension; DM = type 2 diabetes; Mets = metabolic syndrome; HB = hospital based; PB = population based; NA = not available.
*P value for Hardy–Weinberg equilibrium test in controls.