Drinking and Dementia: Is There a Link?
Study Shows Drinkers With Genetic Predisposition to Alzheimer's Disease at Higher Risk
Sept. 2, 2004 -- Drinking alcohol in middle age may increase the risk of late-life dementia in people who are genetically predisposed to develop Alzheimer's disease, according to findings from a Scandinavian study.
Researchers from Stockholm's Karolinska Institute reported that infrequent drinkers have a twofold increase in the risk of dementia in old age among carriers of a gene that has been linked to Alzheimer's. Gene carriers who frequently drink had a threefold increase in risk.
But the findings also show a protective effect for infrequent drinkers who did not have the genetic risk factor. Low-risk teetotalers and frequent drinkers in the study were twice as likely to experience mild cognitive declines later in life as infrequent drinkers.
The findings are reported in the Sept. 4 issue of the BMJ (formerly the British Medical Journal).
"Earlier studies indicated that light to moderate drinking may be protective, but this study shows that the picture is much more complex," researcher Miia Kivipelto, MD, PhD, tells WebMD. "The more people with this susceptibility gene drank, the more their risk for dementia increased."
The study included just more than 1,000 men and women followed for an average of 23 years, who were between the ages of 65 and 79 at follow-up. At enrollment, the participants provided details about their alcohol consumption.
People were considered infrequent drinkers if they drank alcohol less than once a month and frequent drinkers if they drank several times a month.
The researchers also took blood samples to determine which study participants were carriers of the apolipoprotein E genotype. The genotype is an established risk factor for dementia in old age, and as many as one in four Americans are carriers, Kivipelto says.
The Karolinska researchers reported that dementia risk appeared to be directly related to drinking frequency among study participants who were carriers of the gene.
"Our current data indicate that frequent alcohol drinking has harmful effects on the brain, and this may be more pronounced if there is genetic susceptibility," the researchers wrote. "We therefore do not want to encourage people to drink more alcohol in the belief that they are protecting themselves against dementia."