Summary: Researchers report abstaining from drinking alcohol can actually increase dementia risks. Low to moderate alcohol consumption may help to reduce dementia risks.
A recent study led by Dr. Louise Mewton at UNSW’s Centre for Healthy Brain Aging (CHeBA) has reignited the debate about whether low levels of drinking could be positive for health.
The review, published in Addiction, has shown that abstaining from alcohol completely can actually increase the risk of dementia.
In recent decades, the estimated global prevalence of dementia has nearly tripled, from 20.2 million in 1990 to 57.4 million in 2019. By 2050, the projection is that there will be 152 million people globally living with dementia.
According to researchers, risk factor reduction is a fundamental strategy for prevention of dementia—particularly in light of the absence of disease-modifying treatments for dementia. A 2020 report from The Lancet Commission for Dementia Prevention, Intervention and Care estimated that 40% of global dementia cases could be prevented or delayed if 12 key modifiable risk factors for dementia were eliminated—with excessive or harmful alcohol use in midlife newly listed as one of those factors.
Dr. Mewton, who is Leader of the Risk Factors Group at CHeBA, said the inclusion of alcohol as a key risk factor for dementia was based on consistent and robust evidence indicating that chronic heavy alcohol use is associated with dementia and cognitive decline.
“There is controversy over the impact of more moderate levels of alcohol use on the incidence of dementia. Even low levels of alcohol use have been associated with poorer health outcomes, including increased cancer risk.”
“They have also been associated with atrophy in key regions of the brain linked to dementia, like the hippocampus.”
However, in this international study of nearly 25,000 community dwelling adults over the age of 65 including the United States, Australia, Europe, Brazil and the Republic of the Congo, it was consistently shown that abstaining from alcohol was associated with a higher risk of dementia.
“Our data came from 15 studies of healthy aging across six continents, and robust assessment of alcohol use and dementia,” said Dr. Mewton.
“Over the duration of the study 2,124 of the adults developed dementia. What we can conclude from our study is that there doesn’t appear to be a need to intervene in those older adults currently drinking in a light to moderate pattern if dementia prevention is the ultimate goal.”
The researchers found that individuals drinking up to four Australian standard drinks per day had a lower risk of dementia when compared with individuals who did not drink at all. The lower dementia risk associated with drinking alcohol was evident over and above the effects of demographic characteristics (such as age, sex and education), as well as clinical characteristics (such as history of stroke, diabetes and hypertension).
“It has been suggested that the increased risk of dementia associated with abstinence may be the result of including former drinkers who have ceased drinking due to other health conditions or the onset of cognitive problems.”
“However, our study found an increased risk of dementia even after excluding former drinkers from the analysis and after adjusting for relevant demographic and clinical characteristics,” said Dr. Mewton.
Despite this, there may be other characteristics such as social activity that could drive the apparent protective effect of alcohol against dementia, rather than alcohol use per se.
Senior author and Co-Director of CHeBA Professor Perminder Sachdev said that while light to moderate alcohol use may be associated with reduced dementia risk, even low levels of alcohol use have been associated with reduced brain volume, gray matter atrophy and increased white matter hyperintensities, indicating that even low level alcohol use is harmful to the brain.
About this dementia research news
Author: Press Office
Contact: Press Office – CHeBA
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Original Research: Open access.
“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” by Louise Mewton et al. Addiction
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
To synthesize international findings on the alcohol–dementia relationship, including representation from low- and middle-income countries.
Individual participant data meta-analysis of 15 prospective epidemiological cohort studies from countries situated in six continents. Cox regression investigated the dementia risk associated with alcohol use in older adults aged over 60 years. Additional analyses assessed the alcohol–dementia relationship in the sample stratified by sex and by continent. Participants included 24 478 community dwelling individuals without a history of dementia at baseline and at least one follow-up dementia assessment. The main outcome measure was all-cause dementia as determined by clinical interview.
At baseline, the mean age across studies was 71.8 (standard deviation = 7.5, range = 60–102 years), 14 260 (58.3%) were female and 13 269 (54.2%) were current drinkers. During 151 636 person-years of follow-up, there were 2124 incident cases of dementia (14.0 per 1000 person-years). When compared with abstainers, the risk for dementia was lower in occasional [hazard ratio (HR) = 0.78; 95% confidence interval (CI) = 0.68–0.89], light–moderate (HR = 0.78; 95% CI = 0.70–0.87) and moderate–heavy drinkers (HR = 0.62; 95% CI = 0.51–0.77). There was no evidence of differences between life-time abstainers and former drinkers in terms of dementia risk (HR = 0.98; 95% CI = 0.81–1.18). In dose–response analyses, moderate drinking up to 40 g/day was associated with a lower risk of dementia when compared with lif-time abstaining. Among current drinkers, there was no consistent evidence for differences in terms of dementia risk. Results were similar when the sample was stratified by sex. When analysed at the continent level, there was considerable heterogeneity in the alcohol–dementia relationship.
Abstinence from alcohol appears to be associated with an increased risk for all-cause dementia. Among current drinkers, there appears to be no consistent evidence to suggest that the amount of alcohol consumed in later life is associated with dementia risk.