In the new study, Danish researchers found that moderate drinking was associated with a 77 percent lower risk of death among patients with mild Alzheimer’s (defined as a score of 20 or less on the Mini Mental State Exam) than those who consumed one or fewer drinks daily. While previous studies have linked moderate alcohol consumption to many health benefits, including a reduced risk of developing and dying from a chronic disease such as cancer and cardiovascular disease, drinking has also been linked to brain damage. Since Alzheimer's disease is a neurodegenerative disorder, researchers believed any amount of alcohol consumption would have an adverse effect on patients with the condition.
"It came as a surprise," the study's senior author Frans Boch Waldorff told Time. "We thought perhaps if you had a brain disease, you would not tolerate alcohol in the way of people without brain disease."
For the study, researchers analyzed three years of data on 321 people with mild Alzheimer’s disease. Among the cohort, about one in 10 abstained from alcohol, 71 percent consumed one glass of alcohol or fewer per day, 17 percent consumed two to three glasses daily, and 4 percent had more than three drinks per day.
Researchers found no significant difference in death rates among those who reported alcohol abstinence or drank more than three units of alcohol every day compared with those drinking one or fewer daily units.
There could be several explanations for the findings, researchers said. One explanation is that people who drink moderately tend to have a larger social network, which has been linked to a longer life.
"The results of our study point towards a potential, positive association of moderate alcohol consumption on mortality in patients with Alzheimer's disease," researchers said in a statement. "However, we cannot solely, on the basis of this study, either encourage or advise against moderate alcohol consumption in [these] patients."
About 5.3 million of Americans have been diagnosed with Alzheimer’s disease in 2015, according to the Alzheimer’s Association. An estimated 700,000 people in the United States age 65 and older are expected to die with from the neurodegenerative disorder.
The study authors said more research is needed to understand the impact of alcohol on cognitive decline.
Source: Berntsen S, Kragstrup J, Siersma V, Waldemar G, Boch Waldorff F. Alcohol Consumption and Mortality in Patients with Mild Alzheimer’s Diease: A Prospective Cohort Study. BMJ Open. 2015.