Regular use of laxatives and new-onset dementia

A new study published online in the Feb. 22, 2023 issue of the journal Neurology has linked regular use of laxatives to more than 50% higher risk of incident dementia. The risk was particularly higher in those who used only osmotic laxatives.¹

For this study, researchers analyzed data of participants from the UK biobank database. Their average age was 57 years and more than half (~55%) were female. None of the selected participants had dementia at the time of their recruitment. Use of laxatives on most days of the week in the preceding month was considered as regular use for the purpose of the study. Out of the 502,229 people included in the study, 18,235 (3.6%) self-reported regular use of over-the-counter (OTC) laxatives.

A total of 218 subjects (1.3%) who regularly used laxatives developed all-cause dementia over a mean follow up duration of 9.8 years, whereas among those who were not regular users, incident dementia developed in 0.4% (n=1969).

Compared to those who did not regularly use laxatives, the risk of all-cause dementia and vascular dementia was increased among regular users of laxatives with hazard ratio (HR) of 1.51 and 1.65 respectively after adjusting for multiple variables such as age, sex, underlying disease conditions, lifestyle, use of medications and family history.  However, the association between regular use of laxatives and Alzheimer’s disease was non-significant with HR of 1.05. As the number of different laxatives used increased, the risk for all-cause dementia as well as vascular dementia proportionately increased.

Among the regular users, 5800 reported using only one type of laxative. Among those who used only one type of laxative, the risk was 28% higher. In this group, the risk of all-cause dementia increased by 64% among only those who regularly used osmotic laxatives with HR of 1.64. The risk of vascular dementia in this group of patients almost doubled with HR of 1.97. Those who used ≥2 types of laxatives, the risk increased by 90%.

When examining a patient for dementia, a history of regular use of laxatives should also be elicited along with other risk factors. Modifiable risk factors may reduce the risk of dementia and slow down the process. However, the authors point out that their findings do not prove causation and suggest the role of the microbiome-gut-brain axis in this association. They advocate further studies to investigate this association.

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