OR determined with logistic regression for IBS in adoptees with an affected biological or adoptive parent (cohort design)
| Risk factors | Ref | Biological parents | Adoptive parents | ||
| Model 1* | Model 2† | Model 3* | Model 4† | ||
| IBS | 0 | 1.66 (1.17–2.35) | 1.63 (1.14–2.32) | 0.77 (0.44–1.34) | 0.75 (0.43–1.32) |
| Year of birth | 1.01 (1.00–1.02) | 1.01 (1.00–1.02) | 1.01 (1.00–1.02) | 1.01 (1.00–1.02) | |
| Sex | Male | 2.68 (2.29–3.14) | 2.61 (2.23–3.06) | 2.68 (2.29–3.14) | 2.61 (2.23–3.06) |
| County (region) | 1.00 (0.99–1.01) | 1.00 (0.99–1.01) | 1.00 (0.99–1.01) | 1.00 (0.99–1.01) | |
| Education | 1.25 (1.13–1.39) | 1.16 (1.04–1.29) | 1.25 (1.13–1.39) | 1.16 (1.04–1.29) | |
*Univariate model.
†Multivariate model.
IBS, irritable bowel syndrome; Ref, reference.