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Regular laxative use correlated with higher dementia risk in U.K. study

Laxative suppositories on a bathroom counter. Overall, people who used laxatives regularly were 51 percent more likely to develop dementia than their counterparts, according to a study in the journal Neurology. (iStock)

Regular laxative use may be correlated with dementia, according to research published in the journal Neurology in February.

The study looked at a cohort of 502,229 British adults participating in UK Biobank, a long-term initiative that gathered extensive genetic and health information from 40- to 69-year-olds in England, Wales and Scotland between 2006 and 2010. The participants had no history of dementia. Researchers compared those who reported no regular laxative use with those who said they used laxatives most days of the week for the past four weeks in surveys.

The study adjusted for factors that might influence the outcome of the analysis, such as age, diseases, family history of dementia and more. The analysis showed that, over about a 10-year period, 1.3 percent of the participants who regularly used laxatives were diagnosed with dementia, compared with 0.4 percent who didn’t regularly use laxatives. Overall, people who used laxatives regularly were 51 percent more likely to develop dementia than their counterparts.

The type of laxative affected the outcome: People who regularly used osmotic laxatives, which attract water into the colon, were 64 percent more likely to be diagnosed with dementia than their counterparts; they were also more likely to develop vascular dementia than those who used stimulants or bulk-forming laxatives. Those who regularly used more than one type of laxative were at higher risk, too: They had a 28 percent higher risk of developing dementia, and those who regularly used two or more had a 90 percent higher risk.

Researchers write that their analysis supports a hypothesis that laxative use may change the gut microbiome, affecting gut nerves’ signaling ability or possibly producing toxic substances that affect the brain.

The research did not show that laxatives caused dementia, but the association is cause for more research, the scientists write.

“Finding ways to reduce a person’s risk of dementia by identifying risk factors that can be modified is crucial,” Feng Sha, a health statistician and associate professor at the Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences in Guangdong, China, who co-authored the study, said in a news release. “If our findings are confirmed, medical professionals could encourage people to treat constipation by making lifestyle changes such as drinking more water, increasing dietary fiber and adding more activity into their daily lives.”

According to the National Institutes of Health, about 16 percent of U.S. adults and a third of adults over age 60 have constipation symptoms, and up to 18 percent of American adults regularly use laxatives.