A new study with the title “Alcohol use and dementia: a systematic scoping review” published on 05/01/19 carried out a systematic review about the intake of alcoholic beverages and the risk of cognitive impairment.
WHAT’S THE FRAME?
Considering the increasing ageing of populations worldwide, cognitive impairment and dementia are expected to increase and create serious challenges for healthcare providers. The global number of individuals with dementia is projected to triple, from approximately 50 million in 2018 to 152 million in 2050. It is thus very important to find ways of preventing and delaying the start of such cognitive decline.
WHAT DO STUDIES ON ALCOHOL AND DEMENTIA SHOW?
Many studies have shown that excessive consumption of alcoholic beverages is associated with an increased risk of dementia, however, most research findings indicate that such risks are lower among light-to-moderate drinkers than among abstainers.
For the list of studies on Dementia, see dedicated section in the Wine Information Council database.
WHAT DOES THIS NEW PUBLICATION SHOW?
The current review included 28 reviews (from the year 2000 to October 2017). These studies examined associations between the volume of alcoholic beverages consumed, the patterns of alcohol use and cognitive impairment/dementia as well as specific brain functions.
The results showed that light to moderate consumption of alcoholic beverages in middle to late adulthood was associated with a decreased risk of cognitive impairment and dementia in numerous studies, even though the causality could not be established.
On the other hand, excessive alcohol intake and binge drinking was related to changes in the brain structure, cognitive impairment and an increased risk of all types of dementia.
Heavy alcohol use was defined as: > 60g/day for men, >40g /day for women
Light-to-moderate consumption of alcoholic beverages was not defined by the authors.
LIMITATIONS OF THIS STUDY COMPARED TO PREVIOUS PUBLICATIONS
In this review, no distinction was made between the alcoholic beverages; whereas various previous studies have indicated that moderate drinking of wine was protective for dementia.
Rehm J, Hasan OSM, Black, SE, Shield KD, Schwarzinger M, Alcohol use and dementia: a systematic scoping review, Alzheimer’s Research & Therapy 2019, 11:1, https://doi.org/10.1186/s13195-018-0453-0
COMMENTARY by WIC expert Dr. Creina Stockley about this study
“There have been many evidence-based research studies on alcohol and cognition undertaken over the last 10 years, and there are multiple international reviews of these studies. Although there is variation in methodology between studies assessing aspects of cognitive function and alcohol consumption, both current and over a lifetime, the reviews consistently suggest that, on balance, there is a J- or U-shaped relationship between alcohol consumption and the risk of cognitive impairment or dysfunction and the development of dementias such as Alzheimer’s disease. For example, this relationship has been often observed even when taking into account beverage type, drinking patterns and follow-up periods, as well as demographics, genetics, and lifestyle factors such as smoking.
An excellent paper by Neafsey & Collins in 2011included 143 papers published between 1997 and 2011 in a meta-analysis. The meta-analysis showed a 23% reduction in risk of cognitive impairment and dementia for light to moderate consumers compared to non-drinkers, irrespective of whether former drinkers were included with lifetime abstainers (sick quitter hypothesis). Furthermore, in studies that did not separate lifetime abstainers from former drinkers, the finding that alcohol consumption has neuroprotective effects becomes stronger, since former drinkers, especially if many were heavy drinkers, would be expected to be at an increased risk at baseline otherwise. While it is difficult to determine an ‘optimal’ amount because the designs/methods among the studies differ, there are no data suggesting that lifetime or long-term light-to-moderate alcohol consumption exacerbates age-related cognitive impairment/dysfunction.”