Regular laxatives use tied to increased risk of dementia: Study

China: Regular use of laxatives is linked with a 50% higher risk of developing dementia, particularly in those who used osmotic laxatives or multiple laxative types, says a study published in Neurology, the medical journal of the American Academy of Neurology. The study does not prove that laxatives cause dementia. It only shows an association.

Laxatives are a common treatment for constipation. Osmotic laxatives are a type of laxative that attracts water to the colon to soften stool, which has an even greater risk. Other types of laxatives are bulk-forming, stool-softening, and stimulating. 

“Constipation and laxative use is common among middle-aged and older adults,” said study author Feng Sha, PhD, of the Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences in Guangdong, China. “However, regular laxative use may change the gut microbiome, 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.”

Sha noted that osmotic and stimulant laxatives are not recommended for regular use, yet some people use them regularly.

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.

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, 1,969 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.

However, 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.

“Finding ways to reduce a person’s risk of dementia by identifying risk factors that can be modified is crucial,” said Sha. “More research is needed to investigate further 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.”

Reference:

Zhirong Yang, Chang Wei, Xiaojuan Li, Jinqiu Yuan, Xuefeng Gao, Bingyu Li, Ziyi Zhao, Sengwee Toh, Xin Yu, Carol Brayne, Zuyao Yang, Feng Sha, Jinling Tang First published February 22, 2023, DOI: https://doi.org/10.1212/WNL.0000000000207081