The link between bowel disease and dementia

IBD, characterised by abdominal pain and diarrhoea, seems to be associated with an increased risk of developing dementia. — TNS

Carried out by researchers at Taipei Veterans General Hospital and the National Yang-Ming University in Taipei, Taiwan, as well as the University of California, San Francisco, in the United States, a new study looked at data gathered from 1,742 adults aged 45 and above living in Taiwan, who had been diagnosed with one of two types of inflammatory bowel disease (IBD): ulcerative colitis or Crohn’s disease.

Following their diagnosis, the participants had their cognitive health assessed over a period of 16 years and compared to the cognitive health of 17,420 people who acted as a control group.

The control group was matched for various factors including sex, age and underlying health conditions, but didn’t have IBD.

The findings, published online June 25 (2020) in the journal Gut, showed that during the study, more people with IBD developed dementia (5.5%), including Alzheimer’s disease, than those without IBD (1.5%).

After taking into account potentially influential factors, including age and underlying conditions, those with IBD were more than twice as likely to develop dementia as those without IBD.

Their dementia was also diagnosed around seven years earlier than those who were IBD-free.

The researchers also found that out of all the dementias, the risk for Alzheimer’s disease was greatest; those with IBD were six times more likely to develop Alzheimer’s than those without IBD.

The researchers note that as this was an observational study, they cannot establish a cause-and-effect relationship between IBD and dementia.

However, they point out that there is a growing body of evidence to suggest that the bacteria in the gut, called the microbiome, and its communication with the central nervous system can impact our risk of certain health conditions, including cognitive decline.

The cause of IBD is still unclear; however, it is thought to be linked to an impaired immune response that occurs due to changes in the gut microbiome.

Diet and stress are also thought to aggravate the condition.

Ulcerative colitis causes long-lasting inflammation and ulcers in the colon and rectum, while Crohn’s disease causes inflammation of the lining of the digestive tract.

Severe diarrhoea, abdominal pain, fatigue and weight loss are common symptoms in both the conditions.

“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 help slow cognitive decline, conclude the researchers. – AFP Relaxnews