Regular laxative use may increase dementia risk

People who regularly use laxatives, a common treatment for constipation, may have more than a 50% increased risk of developing dementia than people who do not use laxatives, according to a new study published in the journal Neurology. Researchers also found people who used only osmotic laxatives, a type of laxative that attracts water to the colon to soften stool, had an even greater risk.

The study involved 502,229 people in the UK Biobank database 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 regularly using over-the-counter laxatives; regular use was defined as using a laxative most days of the week during the month before the study. This is despite the fact that osmotic and stimulant laxatives are not recommended for regular use.

Over an average of 10 years, 218 of those who regularly used laxatives, or 1.3%, developed dementia. Of those who did not regularly use laxatives, 1969 people, or 0.4%, developed dementia. After adjusting for factors such as age, sex, education, 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 regularly use laxatives.

The risk of dementia also increased with the number of laxative types used. 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. Among people using only one type, only those taking osmotic laxatives had a heightened risk, with a 64% increase compared to those who did not use laxatives.

“Constipation and laxative use are common among middle-aged and older adults,” said study author Dr Feng Sha, from the Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences. “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.

“Finding ways to reduce a person’s risk of dementia by identifying risk factors that can be modified is crucial,” Sha said. “More research is needed to further investigate the link our research found between laxatives and dementia. If our findings are confirmed, medical professionals could encourage people to treat constipation by making lifestyle changes such as drinking more water, increasing dietary fibre and adding more activity into their daily lives.”

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