LOS ANGELES — Former smokers and people with a family history of inflammatory bowel disease are at increased risk for developing ulcerative colitis, data from a case-control study of more than 1,400 patients have confirmed.
Family history of inflammatory bowel disease (IBD) was associated with the highest risk for developing ulcerative colitis.
Those patients with one relative with IBD had an adjusted odds ratio (OR) of 2.48 of having ulcerative colitis; those with two such relatives were at even higher risk (OR 6.8), Dr. Richard Gearry of the department of gastroenterology at Christchurch Hospital in New Zealand said at the annual Digestive Disease Week.
Other risk factors that were significantly associated with development of ulcerative colitis included being a former smoker at diagnosis (OR 1.82) and having used more than four courses of antibiotics a year as an adolescent (OR 1.71).
Factors that appeared to lower the risk included having had an appendectomy (OR 0.45) and being breast-fed for more than 3 months (OR 0.71).
The study included more than 1,400 IBD patients, representing nearly all the IBD patients in the Canterbury, New Zealand, region.
Dr. Gearry and his colleagues recruited 668 patients with ulcerative colitis, 715 patients with Crohn's disease, and 599 sex and age frequency-matched controls.
All participants were asked to complete a self-administered survey containing questions that focused on more than 70 possible environmental risk factors.
About 95% of ulcerative colitis patients, 94% of Crohn's disease patients, and 84% of control subjects completed the survey.
Many of the risk factors identified in the study occurred during childhood, making it critical that researchers and clinicians be watchful of what is happening during that critical time before the development of IBD, Dr. Gearry said.