Light to Moderate Alcohol Use Protective Against Dementia in Older Adults

Megan Brooks

March 07, 2011

March 7, 2011 — Mirroring findings in younger adults, a new study of adults 75 years and older at baseline suggests that drinking light to moderate amounts of alcohol may help protect against the development of dementia.

"There is strong evidence from previous longitudinal studies that [drinking] a small amount of alcohol is associated with lower incidence of overall dementia and Alzheimer dementia," Professor Siegfried Weyerer, PhD, from the Central Institute of Mental Health in Mannheim, Germany, said.

"Unique in our study," he told Medscape Medical News, "is that this result was also found among a large population [75 years and older at baseline] where the mean age was, at 80.2 years, much higher than that in previous studies."

The study was published online March 2 in Age and Ageing.

Drinkers Outnumber Teetotalers

Dr. Siegfried Weyerer

Included in the study were 3202 elderly German individuals free of dementia at baseline who were followed up 1.5 years and 3 years later by means of structured clinical interviews, including detailed assessment of current alcohol consumption and dementia diagnoses.

On the basis of alcohol consumption information available for 3180 of the subjects, 50.0% were abstinent, 24.8% consumed fewer than 1 drink daily (10 g/day), 12.8% drank 1 to 2 drinks daily (10 – 19 g/day), and 12.4% consumed 2 or more drinks daily (≥20 g/day). A small group of 25 participants met criteria for harmful drinking (>60 g/day for men and >40 g/day for women).

Among alcohol drinkers, nearly half (48.6%) drank wine only, 29.0% drank beer only, and 22.4% drank wine, beer, or spirits.

During an average of 3 years, 217 of the 3202 subjects (6.8%) developed dementia; 111 of these subjects (3.5%) developed Alzheimer dementia.

Compared with teetotalers, subjects consuming alcohol were 29% less likely to develop dementia (adjusted hazard ratio [aHR], 0.71; 95% confidence interval [CI], 0.53 – 0.96; P = .0028) and 42% were less likely to develop Alzheimer dementia (aHR, 0.58; 95% CI, 0.38 – 0.89; P = .013).

The protective effect of mild/moderate alcohol consumption on incident dementia was found after controlling for several social factors, such as education, physical and mental health problems including functional impairment or depression, lifestyle factors, or ApoE4 status factors, which have a significant impact on dementia, said Dr. Weyerer.

With regard to quantity of alcohol consumed, the researchers reported all hazard ratios were lower than 1. However, a statistically significant association was found only for subjects consuming between 20 and 29 g of alcohol per day.

A lower risk for incident dementia was found for all types of alcohol, with statistically significant hazard ratios found among those drinking mixed alcoholic beverages.

"In agreement with meta-analyses that include younger age groups, our study suggests that light-to-moderate alcohol consumption is inversely related to incident dementia, also among individuals aged 75 years and older," the study authors conclude.

"People should be aware that we are talking about mild/moderate consumption of alcohol. There is no doubt that long-term alcohol abuse is detrimental to memory function and can cause neurodegenerative disease," said Dr. Weyerer.

Experts Weigh In

Medscape Medical News asked the International Scientific Forum on Alcohol Research to weigh in on the study in relation to prior studies. The forum is a joint undertaking of the Institute on Lifestyle & Health of Boston University School of Medicine in Massachusetts and Alcohol in Moderation of the United Kingdom. Forum members are not paid; members are researchers who share their knowledge and expertise and put recent research into context with other studies.

A statement from the forum provided to Medscape Medical News notes that during the past 31 years (1980-2011), the association between moderate alcohol intake and cognitive function has been investigated in 71 studies comprising 153,856 men and women from various populations with various drinking patterns.

"Most studies showed an association between light to moderate alcohol consumption and better cognitive function and reduced risk of dementia, including vascular dementia and Alzheimer dementia," according to the forum.

However, forum member Erik Skovenborg, MD, of the Scandinavian Medical Alcohol Board and Practitioner, from Aarhus, Denmark, made the point that "since a randomized, controlled study of alcohol consumption and risk of dementia has not been done [and would not be feasible], the jury is still out concerning the importance of confounding."

Dr. Skovenborg noted that "happy people with many friends have the most opportunities for social drinking and in the [current] study alcohol consumption was significantly associated with factors that are protective for the development of dementia: better education, not living alone, and absence of depression.

"However, even after controlling for these and several other factors, the risk for incident dementia was still significantly lower among light-to-moderate alcohol consumers. Even so, it may still be a part of the explanation that old German men and women, who drank alcohol sensibly in old age, also have a healthier lifestyle in terms of physical, dietary, and mental perspectives," Dr. Skovenborg said.

Forum member Roger Corder, PhD, MRPharmS, from the William Harvey Research Institute, Queen Mary University of London, United Kingdom, agrees that "it is very difficult to separate alcohol consumption from other healthy lifestyle factors in populations where moderate drinking is commonplace.

"In this respect," he said, "the [current] study doesn’t correct for a healthy diet, which is also likely very important, as a poor diet is associated with increased risk of dementia due to deficiencies such as low omega-3 fat intake, inadequate vitamin B12, etc. However, it is also known that improved vascular function in alcohol drinkers could account for some element of reduced dementia risk."

Forum member Harvey Finkel, MD, of Boston University Medical Center in Massachusetts, said, although he believes that one "should not start to drink just because one has attained seniority, neither must one stop. Elderly folks handle alcohol with more responsibility than do the young, and they may derive greater health benefits from moderate drinking. Age is not a reason for abstinence," Dr. Finkel said.

The study was funded by the German Federal Ministry of Education and Research. Dr. Weyerer and colleagues have disclosed no relevant financial relationships.

Age Ageing. Published online March 2, 2011. Abstract

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