People who regularly use laxatives may be more than 50% more likely to develop dementia than those who do not use the common constipation treatment, new research suggests.
The study also found that people who used multiple laxatives, or only osmotic laxatives, a type of laxative that attracts water to the colon to soften stool, had an even greater risk.
Other types of laxatives are bulk-forming, stool-softening, and stimulating.
The findings do not prove that laxatives cause dementia, but do suggest an association, the researchers say.
Our research found regular use of over-the-counter laxatives was associated with a higher risk of dementia, particularly in people who used multiple laxative types or osmotic laxatives
Feng Sha, Chinese Academy of Sciences
However, the scientists say that if their findings are confirmed through further studies, doctors could encourage people to treat constipation by making lifestyle changes such as drinking more water, eating more fibre and adding more activity into their daily lives.
Study author Feng Sha, of the Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences in Guangdong, China, said: “Constipation and laxative use are common among middle-aged and older adults.
“However, regular laxative use may change the microbiome of the gut, possibly affecting nerve signalling from the gut to the brain or increasing the production of intestinal toxins that may affect the brain.
“Our research found regular use of over-the-counter laxatives was associated with a higher risk of dementia, particularly in people who used multiple laxative types or osmotic laxatives.”
Researchers also found that while osmotic and stimulant laxatives are both not recommended for regular use, there were many regular users of the medications in this study.
The study involved 502,229 people in the UK biobank – a database of genetic and health information from 500,000 participants nationwide – with an average age of 57 who did not have dementia at the start of the study.
Of this group, 18,235 people, or 3.6%, reported using over-the-counter laxatives most days of the week during the month before the study.
This was considered regular use.
The research, published in the Neurology journal, found that over an average of 10 years, 218 of those who regularly used laxatives, 1.3%, developed dementia.
Of those who did not regularly use laxatives, 1,969 people, or 0.4%, developed dementia.
After taking into consideration factors, including age, other illnesses and medication use, and a family history of dementia, researchers found people who regularly used laxatives had a 51% increased risk of overall dementia compared to people who did not.
For people using one type of laxative, there was a 28% increased risk, compared to a 90% increased risk for people taking two or more types of laxatives.
However, among those only taking osmotic laxatives, there was a 64% increase compared to those who did not use laxatives.
The researchers say more studies are needed to further investigate the link they found between laxatives and dementia.
