Table 1.
Demographics and clinical characteristics of study subjects
| Case–control cohorts | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Sweden |
Italy |
US (Mayo) |
US (UCLA) |
Total |
||||||
| IBS | CTRL | IBS | CTRL | IBS | CTRL | IBS | CTRL | IBS | CTRL | |
| N | 387 | 355 | 319 | 255 | 187 | 114 | 138 | 132 | 1031 | 856 |
| Mean age, year | 42 | 42.5 | 39.6 | 34.8 | 47.9 | 46.6 | 35.0 | 33.5 | 41.4 | 39.4 |
| % F:M | 82:18 | 43:57 | 73:27 | 68:32 | 91:9 | 67:33 | 75:25 | 58:42 | 80:20 | 56:44 |
| IBS-D | 127 | 159 | 89 | 42 | 417 | |||||
| IBS-C | 95 | 128 | 56 | 45 | 324 | |||||
| IBS-M | 162 | 32 | 41 | 34 | 269 | |||||
| IBS-U | 3 | 0 | 1 | 17 | 321 | |||||
| PopCol | Total | IBS* | CTRL* | Microbiota | Diary | |||||
| N | 250 | 30 | 163 | 136 | 133 | |||||
| Mean age, year | 53.6 | 51.6 | 54.7 | 54.8 | 54.7 | |||||
| % F:M | 64:36 | 60:40 | 59:41 | 62:38 | 65:35 | |||||
| IBS-D | 11 | |||||||||
| IBS-C | 5 | |||||||||
| IBS-M | 9 | |||||||||
| IBS-U | 5 | |||||||||
*IBS cases (IBS) and asymptomatic controls (CTRL) were identified based on questionnaire data according to Rome criteria.
Diary, subjects with available daily recordings of defaecation patterns used for correlation analysis with the Val15Phe variant and stool frequency; Microbiota, subjects with available faecal 16S sequencing data; IBS-C, constipation-predominant IBS; IBS-D, diarrhoea-predominant IBS; IBS-M, IBS mixed phenotype; IBS-U, unclassified IBS; PopCol, Population-based Colonoscopy Study; UCLA, University of California, Los Angeles.