Association between regular laxative use and incident dementia in UK Biobank participants

Abstract

AbstractBackgroundUse of OTC laxatives is common in the general population. The microbiome‐gut‐brain axis hypothesis suggests use of laxatives be associated with dementia. We aim to examine the association between regular use of laxatives and incidence of dementia.MethodThis prospective cohort study is based on 476,219 participants aged 40 to 69 years with no history of dementia. Regular use of laxatives is defined as self‐reported use in most days of the week for the last 4 weeks at baseline (2006‐2010). The outcomes are all‐cause dementia, Alzheimer’s disease and vascular dementia, identified from linked hospital admissions or death register (up to 2020).Result18,235 (3.6%) reported regular use of laxatives. Over a mean follow‐up of 9.8 years, 218 (1.3%) participants with regular use of laxatives and 1,969 (0.4%) with no regular use developed all‐cause dementia. Multivariable Cox regression models adjusting for sociodemographics, lifestyle factors, medical conditions and regular medication use showed that regular use of laxatives was associated with increased risk of all‐cause dementia (hazard ratio [HR] 1.51; 95% confidence interval 1.30‐1.75) and vascular dementia (HR 1.65; 1.21‐2.27), with no significant association observed for Alzheimer’s disease (HR 1.05; 0.79‐1.40). The risk of both all‐cause dementia and vascular dementia increased with the number of regularly used laxative types (P‐trend 0.001 and 0.04, respectively). Among the participants who clearly reported that they were using just one type of laxative (n = 5800), only those using osmotic laxatives showed a statistically significantly higher risk of all‐cause dementia (HR 1.64 [1.20‐2.24]) and vascular dementia (HR 1.97 [1.04‐3.75]). These results remained robust in various subgroup and sensitivity analyses.ConclusionRegular use of laxatives was associated with a higher risk of all‐cause dementia and vascular dementia, particularly in those who used multiple laxative types or osmotic laxative.