Crohn's and Colitis Linked to Doubled Risk of Dementia, Study Finds

People with inflammatory bowel disease (IBD) may have a higher risk of developing dementia, according to a study.

Scientists also found that participants with IBD developed dementia almost a decade before those without. The findings were published in the journal Gut.

The researchers believe the link may be down to the relationship between the digestive and nervous systems, known as the gut-brain axis. Past studies have linked psychiatric disorder such as anxiety and depression with IBD, but less work has been done on the condition and dementia.

To arrive at their findings, the team compared data on 1,742 patients with IBD and 17,420 people without, who were matched according to variables that could affect their health, including sex, their access to healthcare, income, and diagnoses with dementia-linked conditions. The information on the participants aged 45 years old and over came from the Taiwanese national health insurance research database.

IBD is an umbrella term for chronic inflammatory conditions including ulcerative colitis and Crohn's disease, characterized by symptoms such as abdominal pain, diarrhea, the sudden urge to use the bathroom, and bloody stools.

The team followed the group for 16 years to see if any individuals developed dementia. Patients with IBD were found to be more likely to have dementia compared with those who didn't, at 5.5 percent of the participants versus 1.4 percent of participants. The risk of developing dementia from the baseline was more than double in those with IBD.

Having IBD for a longer period of time was also linked with having dementia.

People with IBD had a higher chance of developing dementia at an earlier age, at 76 years old on average in patients with IBD, compared with 83 for the controls. Alzheimer's disease was the most common form of dementia among the participants.

There may be a number of explanations for the link between IBD and dementia, the authors said. For example, the long-term effects of chronic inflammation which characterize IBD may affect the brain. Or gut microbes which release certain chemicals may also be to blame.

Co-author Dr. Bing Zhang, a gastroenterologist at the University of California, San Francisco, told Newsweek that while the link may be worrying for those with IBD, he hopes it will stimulate more research to elucidate the shared mechanism between IBD and dementia, and new treatments centered around the gut-brain axis.

Dr Rosa Sancho, head of research at the research charity Alzheimer's Research UK, told Newsweek the methods of the study meant the team could only find an association between having a pre-existing inflammatory bowel condition and dementia, but couldn't explain why. More research is needed to explore this link.

"A better understanding of the dementia risk in people with inflammatory bowel disease may help improve dementia diagnoses and get treatments to people who need them at the earliest opportunity. Only through research like this, will we keep people connected to their families, their worlds and themselves for longer," said Sancho.