Dementia is among the many best concerns of the aging population worldwide, because it involves a lack of mental and physical independence. Alcohol intake has been considered a risk factor for dementia. The incontrovertible fact that it’s modifiable makes it of particular interest.

Study: Changes in Alcohol Consumption and Risk of Dementia in a Nationwide Cohort in South Korea. Image Credit: Mary Long/Shutterstock

A recent study examines the association between alcohol use and dementia risk, in addition to changes in drinking patterns. The outcomes may help shape health advice on drinking.

Introduction

Earlier research showed that dementia is more likely in individuals who drink heavily, while mild to moderate drinking is related to a lower risk. Not much is understood about how changes within the consumption of alcohol are related to dementia risk. Most studies use a snapshot design with a single assessment of alcohol consumption.

The present study, published in JAMA Network, examined a cohort of just about 4 million people in South Korea, with a mean age of 55. The info got here from the Korean National Health Insurance Service database, comprising information logged in from two examinations performed in 2009 and 2011.

The aim was to evaluate the effect of adjusting patterns of alcohol consumption on the dementia risk in comparison with each teetotallers and those that continued to drink heavily. Almost equal parts of men and girls comprised the study. None had pre-existing dementia, cancer or heart problems, and none died inside a yr of the second examination.

Levels of alcohol consumption were classified as none, mild, moderate, and heavy. These categories made up ~55%, ~27%, 11%, and ~7%, respectively. The latter three correspond to <15, 15-29.9, and 30 g/day, respectively.

Over the 2 years between examinations, changes in alcohol consumption were classified as non-drinkers, quitters, reducers, sustainers and increasers – the terms are self-explanatory. Roughly 1 / 4 of mild drinkers, ~8% of moderate and ~7.5% of heavy drinkers quit drinking. Conversely, increasers made up 14% of non-drinkers, ~16% of mild and ~17% of moderate drinkers.

Amongst those that remained teetotallers throughout, the mean age was the very best, with three out of 4 being female and ~85% being non-smokers. Amongst quitters, too, the mean age was higher; more were female and non-smokers, more more likely to exercise recurrently and had lower incomes.

The researchers looked for brand spanking new cases of Alzheimer’s disease (AD), vascular dementia (VD) or other dementia in the entire cohort stratified by drinking patterns and changes in such patterns.

What did the study show?

There have been just over 100,000 cases of dementia from all causes, including almost 80,000 AD and ~11,000 VD cases.

When put next to teetotallers, the chance of dementia was reduced by a fifth amongst those that continued to drink mildly throughout the 2 years between examinations. Amongst sustained moderate drinkers, the reduction was comparable, at ~17%. Heavy drinkers had a small increase in all-cause dementia risk by 8%.

When put next to sustainers on the corresponding level of consumption, those that reduced their heavy drinking to moderate levels had ~10% lower risk of dementia from any cause, but 12% reduction within the AD risk. Similarly, those that began to drink mildly had the identical level of risk reduction, with the identical comparison group.

Those that stopped drinking and those that increased their drinking each showed the next risk compared with those that continued to drink at the identical level. Those that moved from mild to moderate, and from moderate to heavy drinking, respectively, showed a 9% and 16% increase in dementia risk, respectively. The best increase in risk, by 37%, was amongst those that drank mildly at first but moved into heavy drinking by the second examination.

The AD and VD proportions didn’t change significantly.

In a subgroup for which alcohol consumption data was available at a 3rd timepoint 4 years after the primary, there was a 25% reduction in risk amongst those that continued to drink at mild or moderate levels in comparison with teetotallers. Similarly, those that had begun to drink at this level by the second examination and continued to accomplish that two years later showed an 18% reduction in risk. Those that had quit in 2011 and remained quitters in 2013 had the next risk of dementia.

What are the implications?

The findings of the study indicate a lower risk of dementia amongst those that drink mildly to moderately in comparison with lifelong or long-term teetotallers. Again, when heavy drinkers dropped their level of consumption to moderate levels, the chance of dementia was reduced.

For the primary time, the study suggests a discount in dementia risk amongst those that began to drink frivolously after the baseline examination. The researchers add a caveat that self-reported alcohol consumption is often underestimated, nonetheless.

These findings suggest that the brink of alcohol consumption for dementia risk reduction is low.”

There may be a steep increase in dementia risk once the brink of heavy alcohol consumption is crossed, yielding a J- or U-shaped association. Amongst those that drank heavily and recurrently, the chance was increased.

Alcohol in mild to moderate quantities may reduce neuroinflammation, improve platelet function and increase the extent of high-density lipoprotein (‘good cholesterol’). In excess, though, alcohol is a nerve poison and induces a deficiency of many essential nutrients. High alcohol levels also enhance the buildup of the abnormal tau protein within the brain, together with the death of cholinergic neurons, resulting in a relative lack of acetylcholine, a vital neurotransmitter molecule.

The study doesn’t explore disease and death from non-dementia-causes related to alcohol consumption. This, coupled with the high addictive potential of alcohol, might explain why most medical guidelines discourage drinking at any level, even for health reasons.

As well as, individual metabolism and constitutive acetaldehyde dehydrogenase phenotypes determine an individual’s susceptibility to alcohol and the way well people can tolerate the beverage, making it almost not possible to predict the final result on a person basis.

A confounding effect on this study might come from the incontrovertible fact that much drinking is carried out at social gatherings, that are known to be related to reduced dementia risk. Secondly, many or most individuals who quit alcohol accomplish that because they turn out to be sick, often with cardiometabolic disease, which could explain the upper risk of dementia amongst abstainers. Finally, the upper risk amongst abstainers might be explained by their higher age and feminine sex, each of that are dementia risk aspects.