Studies of oral contraceptive usage in CD where isolated colonic disease was separately identified
| Author/ref | Study design | N (total CD) | n/% isolated colonic CD taking OC at onset | n/% all other CD taking OC at onset | OR/RR (95% CI) for OC use compared with healthy controls (when documented by disease location) | OC use in isolated colonic vs all other CD |
|---|---|---|---|---|---|---|
| Rhodes et al50 | Case-control matched for age and year of onset | 37 | 9/12 75% | 11/25 44% | – | NS increased p=0.09 |
| Vessey et al88 | Cohort study in patients attending family planning clinics | 18 | 4/7 57% | 4/11 36% | – | NS increased 0.63 |
| Lashner et al89 | Case-control | 51 (including 8 isolated colonic) | – | – | Isolated colonic OR 0.50 (0.05–5.26) Small bowel only 1.25 (0.34–4.64) Ileocolonic 0.56 (0.20–1.52) | NS reduced (and no significant association in this study between OC use and any CD) |
| Sandler et al90 | Case-control Age-matched and excluding onset before menarche | 184 (including 26 isolated colonic) | – | – | Isolated colonic OR 2.63 (1.00–7.11) Small bowel only 1.33 (0.70–2.53) Ileocolonic 1.52 (0.82–2.83) | NS increased |
| Persson et al91 | Case-control age-matched and sex-matched | 152 | – | – | Isolated colonic RR 3.6 (1.1–12.2) Small bowel only 0.8 (0.3–2.4) Ileocolonic 1.7 (0.8–4.0) | NS increased |
| Katschinski et al92 | Case-control premenopausal | 90 (including 30 isolated colonic) | – | – | Isolated colonic RR 3.2 (1.1–15.3) Small bowel only RR 4.7 (1.6–17.8) Ileocolonic RR 3.8 (1.3–17.0) | NS reduced |
| Khalili et al93 Khalili and Chan94 | Cohort—nurses’ health | 315 (including 141 isolated colonic) | – | – | Isolated colonic HR 4.13 (1.77–9.68) Ileal only HR 2.99 (1.06–8.49) | NS increased |
CD, Crohn's disease; NS, not significant; OC, oral contraceptive; RR, relative risk.