According to a recent study published in Gut, inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn disease, is associated with a more than doubled likelihood of developing dementia. The results also showed that patients with IBD were diagnosed with dementia earlier than those who do not have the disease.1,2

These findings add to the data supporting the connection between the microbiome of the gut and the central nervous system. This connection is commonly called the gut-brain axis, and it has been found to be associated with various dimensions of health and disease.1,2

Although the source of IBD remains unclear, it is believed to be caused by an impaired immune response to changes in the gut microbiome. Prior research also implicated IBD in the development of the neurodegenerative disorder Parkinson disease. However, at the time the research was conducted, it remained unclear whether IBD was linked with any heightened risk of dementia.1,2

For this reason, the researchers in the recently published study looked further into the potential connection between IBD and dementia.1,2

In order to conduct the study, the researchers analyzed data from 1742 people aged 45 years and older who were diagnosed with either ulcerative colitis or Crohn disease between 1998 and 2011. The researchers were able to access data from the Taiwan National Health Insurance program, which was established in 1995 and is a compulsory program for all Taiwanese residents, allowing for a wealth of data for the researchers to access.1,2

The cognitive health of the individuals in the study was then assessed looking at a period of 16 years following the individuals’ IBD diagnoses. Their information was then compared with 17,420 people without IBD who were matched with those with IBD based on their sex, age, access to health care, income, and underlying conditions.1,2

Over this 16-year period, the individuals with IBD developed dementia at a rate of 5.5%, whereas the individuals without IBD developed dementia at a rate of 1.5%. Additionally, those with IBD were diagnosed with dementia on average 7 years earlier than those without.1,2

Ultimately, the researchers found that people with IBD were more than twice as likely to develop dementia than those without, after taking into account other influential factors.1,2

Furthermore, the results showed that development of Alzheimer disease was 6 times more likely in those with IBD than those without.1,2

The researchers found that neither sex nor type of IBD influenced the risk of dementia; however, they did find that the risk of dementia was associated with the amount of time a patient had IBD.1,2

Although this study is observational and is not able to assert cause and effect in relation to IBD influencing dementia risk, the researchers did point to prior research conducted on the subject that showed an association between chronic inflammation and gut microbiome imbalance in connection with cognitive decline.1,2

The researchers made note that education and increased clinical vigilance may be necessary to support patients with IBD in order to manage the increased risk and earlier onset of dementia in these individuals.1,2

REFERENCES
  1. Zhang B, Wang HE, Bai Y, et al. Inflammatory bowel disease is associated with higher dementia risk: a nationwide longitudinal study. Gut. 2020;gutjnl-2020-320789. doi: 10.1136/gutjnl-2020-320789.
  2. Inflammatory bowel disease linked to doubling in dementia risk: And dementia diagnosed around 7 years earlier in those with this gut condition [news release]. BMJ. June 23, 2020. sciencedaily.com/releases/2020/06/200623185240.htm