TUESDAY, Feb. 22 (HealthDay News) -- People with inflammatory bowel disease have double the risk of developing a potentially deadly blood clot (venous thromboembolism) in the legs or lungs as do people in the general public, a new study finds.

Inflammatory bowel disease includes Crohn's disease and ulcerative colitis, both of which can cause abdominal pain, vomiting, diarrhea, weight loss and other problems.

Venous thromboembolism (VTE) -- which includes deep vein thrombosis, pulmonary embolism and superior sagittal sinus thrombosis -- affects about two in every 1,000 people a year in the United States and other developed nations.

Researchers compared the number of new cases of VTE diagnosed between 1980 and 2007 in nearly 50,000 adults and children with IBD and more than 477,000 members of the general public.

After they factored in known VTE risk factors such as a broken bone, cancer, surgery and pregnancy, the researchers concluded that people with IBD were two times more likely to develop VTE than those in the general public.

In general, VTE is more common in older people, whether or not they have inflammatory bowel disease. But this study found that the risk of VTE in people with inflammatory bowel disease was highest in younger age groups, compared with the general population.

In people aged 20 or younger, the risk of pulmonary embolism was six times higher for those with IBD.

Even after adjusting for cardiovascular disease, diabetes, congestive heart failure, hormone replacement therapy or antipsychotic drugs, all of which are known to raise the likelihood of VTE, the risk still remained up to 80 percent higher.

The findings, published online Feb. 21 in the journal Gut, suggest that IBD may be an independent risk factor for clot formation, said the researchers.

More information

The U.S. National Heart, Lung, and Blood Institute has more about deep vein thrombosis.