Is Alcohol Good For You? - Dementia

The press (May 2007) has given wide publicity to what it sees as a study exhaulting the benefits of light drinking (less than a serving of alcohol a day) in preventing dementia. The press statements would lead you to believe that this drinking pattern can lead to a 85% reduction in dementia - if true this would be a really astonishing and effective way of preventing dementia!

The article everyone is talking about is reference 8. The authors of this study state that "moderate drinkers... had a lower rate of progression to dementia than abstainers". The risk reduction as a result of drinking is 0.15 - i.e., 85% reduction in risk compared to non-drinkers. They also conclude that drinking one or more drinks a day has no benefit compared to abstainers.

Putting sensationalism aside, we note the Margin of Error for these numbers: the risk reduction due to having less that one drink a day (compared to abstinence) is 0.03 to 0.78. For those having 1-2 drinks a day it is 0.08 to 2.73! We remind our readers that the "true" result can lie anywhere between the lower and higher numbers for each drinking pattern. Consequently, it is impossible to conclude that 1/2, one or two drinks are better or worse when it comes to preventing dementia. The effect of 1/2 a glass of liquor could be small - a 22% reduction, and 1-2 glasses could in fact, lead to a reduction by a factor of 10! It is simply impossible to deduce anything more precise from this study. Even the mild reduction for light drinkers could be called into question since this type of study (especially given its short period - 3 to 4 years, and its small population - 1445 people) is prone to confounding effects that are hard to determine.

It is entirely possible that alcohol does have some protective effect in preventing dementia, but there is insufficient evidence to draw that conclusion at this time.

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