Table 3.
Characteristics of included studies in the meta-analysis
| First author | Year | Country | No. of IBD (n)a | IBD male (n) | IBD age at diagnosis (years) | IBD type | No. of controls (n) | Control type | Quality score |
|---|---|---|---|---|---|---|---|---|---|
| This study | 2018 | China | 1392 | 634 | Mean 26.9 | Single center | 1392 | Patient | 7 |
| Jung | 2017 | Korea | 15,291 | 9743 | Mean 38.6 | Population | 1,529,100 | Normal | 7 |
| So | 2017 | China | 1603 | 893 | Median CD 40/UC 53 a | Population | 160,300 | Normal | 7 |
| Wadhwa | 2016 | USA | 289,935 | 125,635 | Mean 50.1 | Population | 315,145 | Patient | 7 |
| Jussila | 2013 | Finland | 21,964 | 11,810 | NM | Population | 2,196,400 | Normal | 7 |
| Yano | 2013 | Japan | 770 | 531 | Mean 23.1 | Single center | 77,000 | Normal | 6 |
| Sonu | 2013 | USA | 2686 | 913 | Mean 47.5 | Single center | 1638 | Patient | 6 |
| Jess | 2004 | Denmark | 374 | 157 | NM | Population | 37,400 | Normal | 7 |
aIBD inflammatory bowel disease, NM not mentioned, CD Crohn’s disease, UC ulcerative colitis