Comparison of disease type in familial patients with inflammatory bowel disease stratified by smoking habit
| CD (n (%)) | UC (n (%)) | OR in favour of CD (95% CI) | p Value | |
|---|---|---|---|---|
| An odds ratio of greater than 1 favours the development of Crohn's disease (CD), and less than 1 favours the development of ulcerative colitis (UC). | ||||
| *Favouring UC 2.37 (1.69–3.34). | ||||
| †Favouring UC 5.05 (2.46–11.41). | ||||
| OR, odds ratio; 95% CI, 95% confidence interval. | ||||
| All patients | 333 | 277 | ||
| Never smoked (A) | 124 (37.2) | 162 (58.5) | 0.42 (0.3–0.58)* | <0.0001 |
| Ever smoked (B) | 209 (62.8) | 115 (41.5) | 2.37 (1.69–3.34) | <0.0001 |
| Smoked at diagnosis (B1) | 180 (54.5) | 69 (24.9) | 3.55 (2.51–5.02) | <0.0001 |
| Smoked pre-diagnosis (B2) | 10 (3) | 39 (14.1) | 0.19 (0.09–0.39)† | <0.0001 |
| Smoked post-diagnosis (B3) | 19 (5.7) | 7 (2.5) | 2.33 (0.97–5.62) | 0.053 |