Gene May Boost Dementia Risk in Drinkers
Problem for those with mutation tied to Alzheimer's
THURSDAY, Sept. 2, 2004 (HealthDayNews) -- Drinking alcohol even infrequently may increase your risk of dementia if you're one of the estimated 20 percent of people with a gene that has been linked to Alzheimer's disease, a new study suggests.
The gene, called apolipoprotein e4 (apoE4) allele, appears to alter alcohol's effect on the brain. The gene is also a known risk factor for Alzheimer's, say the Swedish researchers behind the study.
"We found that drinking alcohol at middle age is related to cognitive function and impairment in late life," said Dr. Miia Kivipelto, a researcher at the Aging Research Center at the Karolinska Institute in Stockholm.
Kivipelto's team collected data on 1,018 men and women 65 to 79 years of age. They had had their physical and mental health monitored for about 23 years. Their alcohol consumption was recorded and their apolipoprotein E genotype determined.
"Persons who had the apoE4 and drank infrequently had a four times higher risk of developing dementia compared with people who never drank," Kivipelto said. Frequent drinkers with the apoE4 gene had seven times the risk compared with people who never drank, she added.
Frequent drinking was defined as drinking several times a month. Infrequent drinking was drinking less than once a month, according to the report in the Sept. 4 issue of the British Medical Journal.
"The apoE4 genotype is quite common," Kivipelto said. "Something like 20 to 25 percent of people have this genotype."
For people who did not have the apoE4 gene, drinking did not have a significant effect of developing dementia, Kivipelto noted.
"We did find that infrequent drinkers who did not have the apoE4 allele did have a lower risk of developing dementia compared with those who never drank," Kivipelto said. This has been shown in other studies, she noted. However, this may be due to other factors besides alcohol, Kivipelto said.
"Based on our findings, I would not encourage people to drink more alcohol in the belief that they are medicating themselves against dementia," Kivipelto said.
Dr. Kenneth J. Mukamal, an assistant professor of medicine at Harvard Medical School, said, "The apoE4 findings are particularly interesting, as they dovetail nicely with findings in an older U.S. population.
"It suggests that apoE4 has two important roles in the development of dementia. First, the apoE4 allele is a very strong risk factor by itself. Second, it amplifies the hazards of heavier alcohol consumption on risk of dementia," he added.
The study's findings don't mean that people with the apoE4 gene should not drink alcohol -- or that everyone should get tested for the gene, Mukamal said. "However, those with a family history of Alzheimer's disease should be particularly careful to avoid even moderately heavy intake, perhaps from as early as middle age," he said.
The American Association for Clinical Chemistry can tell you about apolipoprotein E genotyping.