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Dementia risk rises for middle-age abstainers and heavy drinkers

47% higher risk of dementia for abstainers compared to 1-14 units a week drinkers

Adrian O'Dowd

Thursday, 02 August 2018

People who either abstain from alcohol or consume more than the recommended 14 units maximum a week in their middle age appear to have a higher risk of developing dementia, suggests a study* published today in The BMJ.

French and UK researchers also found that the underlying reasons why there is heightened risk are different between the two groups.

With people living longer, numbers of dementia cases are expected to triple by 2050.

In the UK, 14 units of alcohol a week is now the recommended maximum limit for men and women and previous studies have suggested that moderate drinking is associated with a reduced risk of dementia, whereas both abstinence and heavy drinking are linked to a risk of dementia.

However, the evidence is inconclusive and the reasons underlying these associations are unclear.

Therefore, a team of researchers from Inserm (French National Institute of Health and Medical Research) based in France and from University College London in the UK set out to investigate the association between midlife alcohol consumption and risk of dementia into early old age.

They also examined whether cardiometabolic disease has any effect on this association.

They analysed statistics on 9,087 British civil servants aged between 35 and 55 in 1985 who were taking part in the Whitehall II Study, which is looking at the impact of social, behavioural, and biological factors on long-term health.

Participants were assessed at regular intervals between 1985 and 1993 (average age 50) for their alcohol consumption and alcohol dependence.

Alcohol consumption trajectories between 1985 and 2004 were also used to examine the association of long-term alcohol consumption and risk of dementia from midlife to early old age.

Using hospital records, they identified admissions for alcohol-related chronic diseases and cases of dementia from 1991 and the role of cardiometabolic disease.

Results showed that of the 9,087 participants, 397 cases of dementia were recorded over an average follow-up period of 23 years.

After taking into account sociodemographic, lifestyle, and health related factors that could have affected results, the researchers found abstinence was associated with a 47% higher risk of dementia compared to those who consumed between one and 14 units of alcohol a week.

Among those people drinking more than 14 units a week of alcohol, every seven units a week increase in consumption was associated with 17% increase in dementia risk.

A history of hospital admission for alcohol-related chronic diseases was associated with a four times higher risk of dementia.

In abstainers, the researchers found that some of the excess dementia risk was due to a greater risk of cardiometabolic disease.

Because this was an observational study, no firm conclusions could be drawn about cause and effect, but the researchers concluded: “Analyses on alcohol dependence scale and hospital admission for alcohol-related chronic disease strengthen the evidence that excessive alcohol consumption is a risk factor for dementia.

“The present study encourages the use of a lower threshold of alcohol consumption in such guidelines [UK guidelines], applicable over the adult life course, in order to promote cognitive health.”

However, they cautioned that their findings should not motivate people who do not drink to start drinking given the known detrimental effects of alcohol consumption for mortality, neuropsychiatric disorders, cirrhosis of the liver, and cancer.

*Sabia S, Fayosse A, Dumurgier J, et al. Alcohol consumption and risk of dementia: a 23-year follow-up of the Whitehall II cohort study. BMJ 2018;362:k2927. DOI:10.1136/bmj.k2927

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