Table 1.
Characteristics of studies included in the meta-analysis.
| Reference | Geographic area | IBS subtype | Case number | Control number | Cases |
Controls |
HWE |
Quality score | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SS | LS | LL | SS | LS | LL | χ² | P | ||||||
| Wang 2004 | Tianjin | IBS-C, IBS-D, IBS-M | 78 | 44 | 21 | 25 | 32 | 10 | 17 | 17 | 1.89 | 0.169 | 7 |
| Zhang 2006 | Fujian | IBS-C, IBS-D, IBS-M | 145 | 48 | 64 | 49 | 32 | 24 | 20 | 4 | 0.00 | 0.954 | 8 |
| Li 2007 | Guangzhou | IBS-C, IBS-D, IBS-M | 87 | 96 | 46 | 27 | 14 | 55 | 34 | 7 | 0.30 | 0.586 | 8 |
| Wang 2012 | Tianjin | IBS-C, IBS-D, IBS-M | 254 | 120 | 97 | 67 | 90 | 49 | 35 | 36 | 20.15 | 0.000 | 8 |
| Zhang 2012 | Jiangxi | IBS-C | 84 | 103 | 43 | 20 | 21 | 59 | 36 | 8 | 0.56 | 0.453 | 8 |
| Yuan 2014 | Yunnan | IBS-C, IBS-D, IBS-M | 106 | 167 | 45 | 31 | 30 | 20 | 8 | 139 | 108.32 | 0.000 | 8 |
HWE, Hardy–Weinberg equilibrium; IBS, irritable bowel syndrome; IBS-C, constipation-predominant; IBS-D, diarrhea-predominant; IBS-M, mixed.