People with inflammatory bowel disease — either Crohn’s disease or ulcerative colitis — may be at increased risk for dementia, a new study has found.
Researchers matched 1,742 Taiwanese patients who were older than 45 and had inflammatory bowel disease, or I.B.D., with 17,420 controls free of the disease, following them for up to 16 years. The study is online in the journal Gut.
Over all, 5.5 percent of people with I.B.D. developed dementia, compared with 1.4 percent of controls. After adjusting for cerebrovascular disease, hypertension, traumatic brain injury, diabetes, smoking and other risk factors for dementia, they found that people with I.B.D. were almost three times as likely as the controls to develop vascular or other types of dementia, and more than six times as likely to develop Alzheimer’s disease.
Patients with I.B.D. developed dementia at an average age about seven years younger than that of the controls, and the longer they had I.B.D., the more likely they were to become demented.
The lead author, Dr. Bing Zhang, a clinical fellow at the University of California, San Francisco, said that there was an intimate connection between the gastrointestinal tract and the central nervous system, and it’s possible that toxic metabolites from an inflamed gut could pass into the brain.
Still, he said, this is an observational study, and “we could not establish the mechanistic relationship between I.B.D. and dementia.”