New research published in the journal Gut has found that inflammatory bowel disease (IBD) can more than double the risk of developing dementia. This new study adds to the mounting evidence, which suggests that communication between the gut and the central nervous system, known as the ‘gut-brain axis,’ is implicated in various aspects of health and disease.
The term inflammatory bowel disease (IBD) describes a group of disorders in which the intestines become inflamed. It includes ulcerative colitis and Crohn’s disease, which can cause inflammation of the colon and rectum (large bowel or large intestine) with similar symptoms. The cause of inflammatory bowel disease is unclear, yet experts believe that it is thought to develop from an impaired immune response to changes in the gut microbiome.
Microbiome and the Nervous System
To explore the relationship between the resident bacteria (microbiome) and the central nervous system, researchers drew data from 1,742 people aged 45 and above who had been diagnosed with ulcerative colitis or Crohn’s disease between 1998 and 2011. All participants were part of the Taiwan National Health Insurance program, which was set up in 1995 and is compulsory for all Taiwanese residents.
Each participant’s cognitive health was tracked for 16 years following their IBD diagnosis and compared with 17,420 people who didn’t have IBD. The compared group were matched for sex, age, access to healthcare, income, and underlying conditions. During this monitoring period, researchers found that 5.5 percent of the participants with IBD developed dementia. This was compared to 1.5% who developed dementia and didn’t have IBD. Additionally, people with IBD were diagnosed an average of seven years earlier than those without this gut condition.
After accounting for potentially influential factors, people with IBD were found to be twice as likely to develop dementia compared to those without. Researchers also found that of all the dementias, the risk for Alzheimer’s disease was highest.
It was concluded that neither sex nor type of IBD had any bearing on the findings, but the risk of dementia did seem to be associated with the increasing length of time a person had IBD.
Researchers stated, “The identification of increased dementia risk and earlier onset among patients with IBD suggest that they might benefit from education and increased clinical vigilance,” to slow cognitive decline and improve quality of life.
As an observational study, they do stress that the findings could not establish cause and effect. However, it does add to the mounting evidence suggesting that chronic inflammation and an imbalance in the gut bacteria may be potential contributors to cognitive decline.