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.

The consumption of alcohol and tobacco are considered unhealthy habits, harmful to health, and are related to the development of pathologies such as cardiovascular diseases (CVD), digestive system diseases, hypertension, diabetes mellitus, or cognitive deterioration among others, representing a serious problem for public health (1–3). Indeed, alcohol consumption increases the risk of dementia, especially early-onset dementia (4–10), indicating a negative impact of alcohol consumption on different areas of familial, social, and cultural wellbeing (11–13).

The alcohol consumption recommendations established by the WHO are 30 g for men and 20 g for women, 3 standard drinking units (SBUs), and 2 SBUs, respectively, as 1 SBU corresponds to 10 g of pure alcohol (14). It has been suggested that low-to-moderate alcohol consumption could be beneficial to the health of middle-aged (15) and older subjects (16–18), leading to a J-shaped or inverse U-shaped association between alcohol and cognitive function, heart disease (19, 20) and all-cause mortality (21). Furthermore, and according to previous systematic reviews, moderate alcohol consumption appears to be associated with a lower risk of cognitive impairment, dementia, Alzheimer’s disease, and better cognition (9, 22), which may be linked to its effects on cardiovascular disease (22). These effects of alcohol consumption are not observed for vascular dementia (9), neither for heavy, chronic, and irregular alcohol consumption which are associated with an increased risk of cognitive impairment or dementia (13).

Further analysis of the data indicates that the effect of alcohol depends on the type of alcoholic beverage analyzed (20), distinguishing between beer, white wine, red wine, fortified wine, and spirits (23). Although wine consumption has been associated with a reduced risk of cerebrovascular disease and Alzheimer’s disease (24), there is controversy as to whether these benefits are also reported for beer and other spirits (4, 25). The specific characteristics of wine could be the reason for its benefits. Wine is produced from the fermentation of grapes, and yeast is added, causing the sugars present in the grapes to be converted into ethanol, endowing wine with different nutritional properties. It has been reported that some components of wine, such as resveratrol, phenolic acids, and flavonoids, may exert positive health effects (26). Previous research has shown that these components reduce free cholesterol (27), have a cardioprotective effect (28), induce endothelial relaxation (29), activate NO synthase (30), inhibit platelet aggregation, and (31) prevent oxidation of low-density lipoproteins (LDL) cholesterol (32).

Regardless of previous research, the evidence on the association between wine consumption and the risk of cognitive decline remains inconclusive (9, 14, 22, 33). This systematic review and meta-analysis aim to examine the strength of the association between wine consumption and cognitive decline and to analyze whether this association varies depending on the wine consumption level or is affected by individual and study characteristics, including the mean age, percentage of women participants, and follow-up time.

reference link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9133879/

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


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