Largest study of its kind finds alcohol use biggest risk factor for dementia

February 20, 2018

Science Daily/Centre for Addiction and Mental Health

Alcohol use disorders are the most important preventable risk factors for the onset of all types of dementia, especially early-onset dementia. This according to a nationwide observational study of over one million adults diagnosed with dementia in France.

This study looked specifically at the effect of alcohol use disorders, and included people who had been diagnosed with mental and behavioural disorders or chronic diseases that were attributable to chronic harmful use of alcohol.

Of the 57,000 cases of early-onset dementia (before the age of 65), the majority (57%) were related to chronic heavy drinking.

The World Health Organization (WHO) defines chronic heavy drinking as consuming more than 60 grams pure alcohol on average per day for men (4-5 Canadian standard drinks) and 40 grams (about 3 standard drinks) per day for women.

As a result of the strong association found in this study, the authors suggest that screening, brief interventions for heavy drinking, and treatment for alcohol use disorders should be implemented to reduce the alcohol-attributable burden of dementia.

"The findings indicate that heavy drinking and alcohol use disorders are the most important risk factors for dementia, and especially important for those types of dementia which start before age 65, and which lead to premature deaths," says study co-author and Director of the CAMH Institute for Mental Health Policy Research Dr. Jürgen Rehm. "Alcohol-induced brain damage and dementia are preventable, and known-effective preventive and policy measures can make a dent into premature dementia deaths."

Dr. Rehm points out that on average, alcohol use disorders shorten life expectancy by more than 20 years, and dementia is one of the leading causes of death for these people.

For early-onset dementia, there was a significant gender split. While the overall majority of dementia patients were women, almost two-thirds of all early-onset dementia patients (64.9%) were men.

Alcohol use disorders were also associated with all other independent risk factors for dementia onset, such as tobacco smoking, high blood pressure, diabetes, lower education, depression, and hearing loss, among modifiable risk factors. It suggests that alcohol use disorders may contribute in many ways to the risk of dementia.

"As a geriatric psychiatrist, I frequently see the effects of alcohol use disorder on dementia, when unfortunately alcohol treatment interventions may be too late to improve cognition," says CAMH Vice-President of Research Dr. Bruce Pollock. "Screening for and reduction of problem drinking, and treatment for alcohol use disorders need to start much earlier in primary care." The authors also noted that only the most severe cases of alcohol use disorder -- ones involving hospitalization -- were included in the study. This could mean that, because of ongoing stigma regarding the reporting of alcohol-use disorders, the association between chronic heavy drinking and dementia may be even stronger.

https://www.sciencedaily.com/releases/2018/02/180220183954.htm

For white middle class, moderate drinking is linked to cognitive health in old age

August 1, 2017

Science Daily/University of California - San Diego

Older adults who consume alcohol moderately on a regular basis are more likely to live to the age of 85 without dementia or other cognitive impairments than non-drinkers, according to a new study.

Previous studies have found a correlation between moderate alcohol intake and longevity. "This study is unique because we considered men and women's cognitive health at late age and found that alcohol consumption is not only associated with reduced mortality, but with greater chances of remaining cognitively healthy into older age," said senior author Linda McEvoy, PhD, an associate professor at UC San Diego School of Medicine.

In particular, the researchers found that among men and women 85 and older, individuals who consumed "moderate to heavy" amounts of alcohol five to seven days a week were twice as likely to be cognitively healthy than non-drinkers. Cognitive health was assessed every four years over the course of the 29-year study, using a standard dementia screening test known as the Mini Mental State Examination.

Drinking was categorized as moderate, heavy or excessive using gender and age-specific guidelines established by the National Institute on Alcohol Abuse and Alcoholism. By its definition, moderate drinking involves consuming up to one alcoholic beverage a day for adult women of any age and men aged 65 and older; and up to two drinks a day for adult men under age 65. Heavy drinking is defined as up to three alcoholic beverages per day for women of any adult age and men 65 and older; and four drinks a day for adult men under 65. Drinking more than these amounts is categorized as excessive.

"It is important to point out that there were very few individuals in our study who drank to excess, so our study does not show how excessive or binge-type drinking may affect longevity and cognitive health in aging," McEvoy said. Long-term excessive alcohol intake is known to cause alcohol-related dementia.

The researchers said the study does not suggest drinking is responsible for increased longevity and cognitive health. Alcohol consumption, particularly of wine, is associated with higher incomes and education levels, which in turn are associated with lower rates of smoking, lower rates of mental illness and better access to health care.

The UC San Diego School of Medicine research team adjusted the statistical analyses to remove confounding variables, such as smoking or obesity, but noted the study is based only on statistical relationships between different demographic factors, behaviors and health outcomes. There remain on-going debates about whether and how alcohol impacts lifespan or potentially protects against cognitive impairments with age.

One of the study's advantages, however, is that the data derive from a relatively homogenous population in a geographically well-defined area. All of the 1,344 older adults (728 women; 616 men) who participated in the study are from Rancho Bernardo, a white-collar, middle-to-upper-middle-class suburb in San Diego County. More than 99 percent of the study participants, tracked from 1984 to 2013, are Caucasian with at least some college education.

"This study shows that moderate drinking may be part of a healthy lifestyle to maintain cognitive fitness in aging," said lead author Erin Richard, a graduate student in the Joint San Diego State University/UC San Diego Doctoral Program in Public Health. "However, it is not a recommendation for everyone to drink. Some people have health problems that are made worse by alcohol, and others cannot limit their drinking to only a glass or two per day. For these people, drinking can have negative consequences."

https://www.sciencedaily.com/releases/2017/08/170801131212.htm