People with inflammatory bowel disease twice as likely to develop dementia than those without it: Study
Inflammatory bowel disease (IBD) -- a chronic inflammatory condition consisting mainly of ulcerative colitis and Crohn’s disease -- has now been associated with more than doubling in the risk of developing dementia. Moreover, dementia was diagnosed around seven years earlier in people with IBD than it was in those without this gut condition, according to the findings of a large population-based study. “This population-based cohort study demonstrates significant association between IBD and subsequent development of dementia. Dementia was diagnosed at an earlier age among patients with IBD, and disease risk appeared to increase with IBD chronicity. These findings highlight the need for future research to elucidate the relationship between IBD and dementia,” say researchers in the study published in the journal Gut. The team had researchers from the University of California, San Francisco, US; Taipei Veterans General Hospital, Taiwan; and National Yang-Ming University, Taipei.
According to experts, evidence suggests that communication between the gut, its resident bacteria (microbiome), and the central nervous system, known as the 'gut-brain axis,' is implicated in various aspects of health and disease. While the cause of inflammatory bowel disease is not clear, it is thought to develop from an impaired immune response to changes in the gut microbiome. The research team says that recently published research suggests that IBD may have a role in the development of another neurodegenerative disorder, Parkinson's disease. But it was not clear if IBD may also be linked to a heightened risk of dementia. To understand this further, the researchers drew on data for 1,742 people, aged 45 and above, who had been diagnosed with either ulcerative colitis or Crohn's disease between 1998 and 2011 and registered with the Taiwan National Health Insurance program. This was set up in 1995 and is compulsory for all Taiwanese residents.
The team tracked their cognitive health for 16 years following their IBD diagnosis and compared with that of 17,420 people who were matched for sex, age, access to healthcare, income, and underlying conditions, but who did not have IBD. During the monitoring period, a larger proportion of those with inflammatory bowel disease developed dementia (5.5%), including Alzheimer's disease, than those without it (1.4%). Additionally, people with IBD were diagnosed with dementia an average of seven years earlier (76) than those without IBD (83).
After taking account of potentially influential factors, including age and underlying conditions, the team concludes that people with IBD were more than twice as likely to develop dementia as those without. Neither sex nor type of IBD had any bearing on the findings. But the risk of dementia seemed to be associated with increasing the length of time a person had IBD. Among dementia types, the risk for Alzheimer's disease was the greatest: those with IBD were six times as likely to develop this as were those without IBD. “Overall incidence of dementia among patients with IBD was significantly elevated (5.5% versus 1.4% among controls). Patients with IBD were diagnosed with dementia at 76.24 years old on average, compared with 83.45 among controls. The hazard ratio of developing dementia among patients with IBD was 2.54,” says the study.
The researchers were not able to gather information on potentially influential lifestyle factors, such as diet and exercise, or assess the impact of anti-inflammatory drugs prescribed. But they point to previously published research, indicating chronic inflammation and an imbalance in gut bacteria as potential contributors to cognitive decline. The authors say that the clinical implications of their findings include vigilance of dementia among elderly patients with IBD, support, and education for patients with IBD and their caregivers, and early detection and timely medical care. “Global disease burden of IBD and prevalence of dementia continue to rise alongside the world population’s average life expectancy. The identification of increased dementia risk and earlier onset among patients with IBD suggest that this population may benefit from education and increased clinical vigilance through a multidisciplinary approach,” says the research team.