Previous studies have linked moderate drinking with a reduced risk of cardiovascular disease and mortality.
Previous research has indicated, however, that moderate drinking might not carry these risks.
"In fact, moderate alcohol consumption seems to have beneficial effects on various parts of our health, decreasing the risk of cardiovascular disease and mortality," write the authors of the new study.
Alzheimer's disease is a leading cause of mortality in the US. The Alzheimer's Association state that an estimated 700,000 people in the US aged 65 and above will die from the disease by the end of 2015.
Deaths attributed to Alzheimer's have also increased over the last 15 years, rising by 71% between 2000 and 2013. As such, research into slowing the effects of this neurodegenerative disorder are becoming increasingly important.
The authors of the new study wanted to find out if the decreased risk of mortality potentially conferred by moderate drinking would apply to people with early-stage Alzheimer's disease, particularly in light of the fact that alcohol is known to damage brain cells.
To do this, the researchers analyzed data taken from the Danish Alzheimer's Intervention Study (DAISY) on 321 people with early-stage dementia or Alzheimer's disease and their primary carers. DAISY evaluated the impact of a year-long support program, tracking the progress of its participants for 3 years afterward.
Moderate drinking linked to a 77% lowered risk of death
Of the 321 participants with Alzheimer's disease, 17% drank 2-3 units of alcohol daily. Around 8% drank no alcohol, 71% drank 1 unit or fewer daily and 4% drank more than 3 units daily.
During the follow-up period, a total of 16.5% of the participants died. The researchers found that those who drank 2-3 units of alcohol daily had a 77% lower risk of death in comparison with those who drank 1 unit or fewer per day.
Even after adjusting for potentially confounding factors such as age, gender, quality of life and smoking status, the researchers found that this association remained.
Fast facts about moderate drinking
- The recommended alcohol limit for women is lower than the limit for men
- Women absorb more alcohol into their bloodstream than men of the same weight
- A medium (175 ml) glass of 12% red wine contains about 2 units of alcohol.
A potential explanation for this result was that those who drank small amounts of alcohol were already in the terminal phase of their life, leading to an apparent positive association between drinking and reduced mortality.
Further analysis of DAISY, omitting data taken from the first year of follow-up, did not affect the association, however, ruling out this theory.
Another potential explanation proposed by the authors is that patients with moderate alcohol intake may have a richer social environment than other patients, a factor that has previously been suggested to improve quality of life and mortality.
"The results of our study point towards a potential, positive association of moderate alcohol consumption on mortality in patients with Alzheimer's disease," the authors conclude. "However, we cannot solely, on the basis of this study, either encourage or advise against moderate alcohol consumption in [these] patients."
As the study is an observational one, more research is required to follow up these findings. The authors suggest that further studies could focus on the association between alcohol consumption and cognitive decline in patients with Alzheimer's disease.