Increased risk for all-cause dementia in people who abstain from alcohol

Alcohol abstinence increases the risk for dementia in later life, according to a recent study published in the journal Addiction. Furthermore, neuroimaging records suggest that even low alcohol consumption levels could harm brain health, as does the dose-response relationship between alcohol use and systemic diseases, such as metabolic diseases and certain cancers. 

Study: The relationship between alcohol use and dementia in adults aged more than 60 years: a combined analysis of prospective, individual-participant data from 15 international studies. Image Credit: Ground Picture / Shutterstock

Background

Dementia generally affects the elderly and geriatric patients. It is a group of symptoms characterized by diminished cognition, memory, attention, communication, reasoning, and visual perception. The syndrome impairs the patient's quality of life and imposes severe physical, psychological, social, and economic burdens.

The global prevalence of dementia has been rising over the last two decades, and the projected numbers by 2050 are more than seven times the cases recorded in 1990. Dementia is preventable; nearly 40% of the cases can be prevented and delayed by modifying its 12 key risk factors – according to a 2020 report published in Lancet Commission for Dementia Prevention, Intervention and Care.

One of the critical risk factors mentioned in the report was excessive alcohol consumption in mid-life – owing to the significant neurotoxic effects of ethanol on the brain. In addition, population-based studies have also associated heavy alcohol use with dementia. 

However, some reports suggest that light-to-moderate alcohol use can reduce alcohol risk among abstainers. In other words, individuals who regularly consume alcohol in low doses could be at a lower risk for dementia than those who do not intake alcohol at all.

The study

This review included data from prospective epidemiological cohort studies conducted across six continents to examine the relationship between alcohol and dementia. The aim was to bridge the gap between findings from high-income countries and low- to middle-income countries. 

The study included 15 epidemiological cohort studies – members of the Cohort Studies of Memory in an International Consortium (COSMIC) collaboration. Individuals with dementia diagnosis at baseline, those without follow-up after dementia assessment, and those with no alcohol use records were excluded. 

The study included individuals above 60 years of age. Most of the cohorts hailed from high-income countries; among the low- and middle-income countries, cohorts from Brazil and the Republic of Congo were included. 

Findings

The final sample analyzed comprised 24,478 individuals with a mean age of 71.8 years at baseline. Among these, 58.3% were females, and 54.2% were current drinkers. 

Notably, the risk of dementia was greater among alcohol abstainers than occasional, light- to moderate-, and moderate- to heavy drinkers. This result was consistent among the female subjects and the fully adjusted and competing risk models. However, in fully adjusted models and in those adjusted for competing for risk for death among females, no association was found between alcohol use and dementia.

Neither lifetime abstainers nor past drinkers had a different dementia risk.

Consistently, there was no difference in the competing risk of death in the subsample and adjusted model analyses.

Moderate drinking – alcohol intake of up to 40 g/day was associated with lower dementia risk relative to lifetime abstinence. These findings were consistent among men and women and in the adjusted models.

The dose-response analysis conducted among current drinkers did not show any significant variation in dementia risk based on the amount of alcohol consumed. Based on current alcohol intake status, neither men nor women showed any variation in dementia susceptibility after adjusting for demographic and clinical characteristics.

Furthermore, dementia risk did not differ between daily drinkers and occasional drinkers. The same was true in comparison between lifetime abstainers and current drinkers.

Continent-wise analyses for the association between alcohol use and dementia risk, including – Europe, Oceania (Australia), North America, and Asia (Korea), revealed non-linear relationships for Europe, North America, and Asia. However, a statistically significant difference could not be established. Meanwhile, results from Oceania depicted a preventive effect of alcohol use in moderation relative to lifetime abstinence.

Among current users, minimal drinking – up to 0.3 mg per day, posed a lower dementia risk among Europeans. Whereas, populations in Oceania gained a protective effect from alcohol use in all moderations and North American light-moderate drinkers had a higher dementia preponderance compared to the minimal drinkers. Alcohol consumption, however, did not change Asians' dementia predisposition.

It was suggested that the findings must be balanced against investigational evidence that confirms the harmful effects of alcohol use, even in moderation, on brain health. 

Written by

Nidhi Saha

I am a medical content writer and editor. My interests lie in public health awareness and medical communication. I have worked as a clinical dentist and as a consultant research writer in an Indian medical publishing house. It is my constant endeavor is to update knowledge on newer treatment modalities relating to various medical fields. I have also aided in proofreading and publication of manuscripts in accredited medical journals. I like to sketch, read and listen to music in my leisure time.