Latest scientific news 28 January 2016

Moderate consumption of alcoholic beverages in Alzheimer’s disease and dementia seems beneficial

For the first time, the association between the intake of alcoholic beverages and mortality in patients with Alzheimer Disease (AD) was examined. The results give important knowledge on how a very common lifestyle factor – alcoholic beverages – can affect the lives of people diagnosed with AD specifically. Patients consuming moderately (2-3 units/day) had a significant lower mortality over a period of 36 months.

An increasing prevalence of Alzheimer’s Disease (AD) and dementia with increasing age combined with a growing proportion of elderly will lead to a dramatic rise in the number of people suffering from dementia worldwide. In the past years several prospective cohort studies have shown that light-to-moderate consumption of alcoholic beverages can reduce the risk of dementia and cognitive decline. Most of this evidence does not distinguish between the different types of alcoholic beverages. However, some studies have suggested that the strongest protection against cognitive decline is associated with moderate red wine consumption.

Currently, the mechanisms for these protective effects of alcohol are not understood.  According to one hypothesis, alcohol increases the blood circulation to the brain and decreases inflammation. It should be noted that inflammation is strongly implicated in the severity and progression of diseases like Alzheimer’s diseaseAlzheimer’s disease (AD) is a form of dementia. AD and other types of dementia are most common in ... (AD).  Experiments on isolated neurons (nerve cells that send and receive electrical signal over long distances within the body) suggest that small amounts of alcohol can “precondition” the brain cells to deal with stressful conditions, helping to suppress inflammation and prevent cognitive deterioration.

While there are numerous prospective studies that have focused on the intake of alcoholic beverages as a risk factor for dementia, cardiovascular and cancer mortality in healthy subjects, virtually no attention has been paid so far to the effect of alcohol consumption in patients with AD.

Two recent studies now fill this gap.

In the Danish Alzheimer’s Intervention Study (DAISY), a longitudinal multi-centre randomised controlled study, data regarding the current daily consumption of alcoholic beverages were obtained from 321 patients recently diagnosed with mild Alzheimer’s disease (AD) at inclusion to the study. The all-cause mortality was retrieved from The Danish Civil Registration System during a period of 36 months after baseline. The analysis – adjusted for a range of potential confounders – demonstrated a significantly reduced mortality by 77 % for patients consuming alcoholic beverages moderately (2-3 units/day) compared with patients who had 1 or <1 unit/day.

Several possible explanations for such a protective association between moderate alcohol intake and mortality in patients with AD are discussed. First, small amounts of alcohol may have a health preserving effect per se as indicated in many studies in healthy subjects. In addition, AD patients who continue to consume moderate amounts of alcoholic beverages may have a richer social environment, which could improve the quality of life and thus perhaps lower mortality. More research is urgently needed to clarify these relationships (1).

In a second prospective cohort study in Norway, the 25,635 participants aged between 60 and 80 years at entry to the study were followed up for 17 years. During this period, 12,139 patients died, of which 1,224 had a diagnosis of dementia in their death certificate. After adjusting for relevant cofounders, the analysis revealed that the risk of dementia-related death was significantly higher among elderly abstainers (33%) than among those who moderately consumed alcoholic beverages.

(1)      Berntsen S, Kragstrup J, Siersma V, et al. Alcohol consumption and mortality in patients with mild Alzheimer’s disease: a prospective cohort study. BMJ Open. 2015;5(12):e007851.

For more information about this article, read the scientific abstract here.

(2)      Ormstad H, Rosness TA, Bergem AL, et al. Alcohol consumption in the elderly and risk of dementia related death – a Norwegian prospective study with a 17-year follow-up Int J Neurosci. 2016 Feb;126(2):135-44.

For more information about this article, read the scientific abstract here.