And just when you thought things could not get any worse, a study was published last week showing that having IBS could cause you to be more at risk from dementia As far as the design was concerned, it was almost perfect. The scientists, all from Taiwan, studied the health insurance records of a million people and from these identified a cohort of 32,000 of patients over 20 years old with IBS that was newly diagnosed between 2000 and 2011 and a matched cohort of 129,000 who did not have IBS. They then followed them up every year for up to twelve years, looking for evidence of dementia. Significantly more people in the IBS cohort developed dementia. The numbers were not great; the difference was between 4.9 per 1000 patient years in the IBS versus 3.6 per 1000 patient years in the group that did not have IBS and was only statistically significant in those patients over the age of 50 upon enrolment. To put it into perspective, this indicates that slightly less than 5 patients out of every thousand with IBS are likely to develop dementia in any one year of the study compared with between 3 and 4 people out of every thousand people per year without IBS. Over the 12 year course of the study, this amounts to added risk of dementia for IBS of 15 out of a 1000 patients (1.5%). The risk of getting dementia is greater in those who had other established risk factors, such as head injury, stroke, diabetes, epilepsy and depression. Nevertheless the study also showed that people with IBS were also more likely to have these other conditions (co-morbidities).
It has been known for many years that depression and IBS were associated with each other. Last year a study was published from a group in Seattle, that showed that administering the antidepressant, amitriptyline to people over the age of 50, even at low dosage also increased the risk of dementia. Amitriptyline is advocated for depression and also at low dose for IBS.
The authors of this study point to the perturbations of the brain gut axis for the association between IBS and brain and mental illness, identifying the possibility that changes in the composition of gut bacteria might predispose to both. Although it is known that alterations in the colonic microbiome can alter brain function, scientists are are still a long way off knowing that specific microbial disturbances might give rise to IBS or dementia. On the other hand, it is well established that dementia is more likely after prolonged stress, depression and sleep disturbance, produced for example from severe and or repeated trauma.
If we look at the association between IBS, depression and dementia from the perspective of a post traumatic stress disorder, the evidence seems clear. While earlier studies had shown clearly that major trauma, childhood abuse, sexual abuse, conflict, incarceration could leave a residue of physical and mental symptoms, more recent observations indicate that frequent lifetime trauma, such as as death of a loved one, divorce, break up of a love affair, car accident, natural disaster and mental abuse are more was common among adults with IBS and may predispose to dementia. Depending on what happened, how prolonged, the meaning in relation to previous life experience, such occurrences may leave people vulnerable to long term illness and dementia.
Illness may be bad luck, but we can all influence our luck. We can be mindful of the risks of certain decisions, take time to weigh them up and get help if things go wrong. You have only one life. Guard it well.