Table 1.
Characteristics of the studies included in the statistical analyses
| First author, year, reference number | Country | Study design | IBS diagnostic criteria | Number of participants (IBS/HC) | Age (IBS/HC), years | Percentage of females (IBS/HC) |
|---|---|---|---|---|---|---|
| Bianchi Porro et al. (1983)35 | Italy | Case‐control | Unspecific abdominal complaint (primarily colicky abdominal pain and/or intermittent diarrhea or dyspepsia) for at least 1 year without any organic disease | 77/40 | Group 1: mean 42.2 (range: 19‐53); group 2: mean 41.2 (range: 18‐54)/mean 35.05 (range: 18‐55) | 51.9/52.5 |
| Gwee et al. (1996)36 | UK | Case‐control | Rome criteria | 22/53 | Median 34 (IQR: 23.5‐51)/median 36 (IQR: 27‐52) | 77/36 |
| Vesa et al. (1998)37 | Finland | Case‐control | Rome criteria | 63/364 | Mean 51 ± 9 SD/mean 50 ± 9 SD | 68/50 |
| Goldstein et al. (2000)38 | Israel | Case‐control | Rome criteria | 94/145 |
Women: mean 44.4 ± 17.5 SD; men: mean 42.7 ± 18.6 SD/women: mean 49.6 ± 18.9 SD men: mean 35.7 ± 15.7 SD |
No data |
| Vernia et al. (2001)27 | Italy | Case‐control | Rome criteria | 503/336 |
Women: mean 37.8 ± 13.9 SD men: mean 36.2 ± 13.9 SD / women: mean 36.1 ± 14.8 SD men: mean 32.1 ± 13.5 SD |
66.7/65.1 |
| Parry et al. (2002)39 | UK | Case‐control | Rome II | 16/18 | Mean 44.4 (range 25‐76) | No data/55.5 |
| Lanng et al. (2003)40 | Denmark | Case‐control | Kay and Jørgensen criteria: More than weekly experience of abdominal pain and distension and in addition either borborygmi or altering stool consistency | 32/26 | Mean 51.8/mean 52.8 | 75/53.8 |
| Farup et al. (2004)41 | Norway | Case‐control | Rome II | 82/105 | Mean 48.8/mean 46.3 | 68/78 |
| Saberi‐Firoozi et al. (2007)42 | Iran | Case‐control | Rome II | 215/1763 | Mean 49.9 ± 11.14 SD | 64.2 |
| Corlew‐Roath et al. (2009)43 | USA | Case‐control | Rome III | 66/55 | All participants over 18 years | 86/62 |
| Yakoob et al. (2011)44 | Pakistan | Case‐control | Rome III | 119 /115 | Mean 35 ± 13 SD (range: 18‐74)/mean 36 ± 15 SD (range: 18‐80) | 26.05/33.04 |
| Kumar et al. (2012)45 | India | Case‐control | Rome III | 150/252 | Mean 36.7 ± 11.8 SD/mean 37.2 ± 11.5 SD | 24/22 |
| Yang et al. (2013)26 | China | Case‐control | Rome III | 60/60 | Mean 40.8 ± 11.7 SD/mean 40.8 ± 15.2 SD | 51.6/48.3 |
| Xiong et al. (2017)46 | China | Case‐control | Rome III | 109/50 | Mean 36.0 ± 12.2 SD/mean 34.8 ± 13.3 SD | 47.7/48 |
HC, healthy control; IBS, irritable bowel syndrome; IQR, interquartile range; SD, standard deviation.