A study published in the BMJ investigates the association between alcohol consumption and mortality in patients recently diagnosed with mild Alzheimer’s disease (AD).
The data reported were collected as part of the Danish Alzheimer’s Intervention Study (DAISY), a longitudinal multicentre randomised controlled study on the efficacy of psychosocial intervention in patients with mild AD across five county districts in Denmark. 321 patients with mild AD (Mini-Mental State Examination ≥20) were included.
Information was collected on how much alcohol people with early stage dementia or Alzheimer’s drank every day. 8% drank no alcohol, 71% drank 1 or fewer units a day, 17% drank 2-3 units and 4% drank more than 3 units daily
During the monitoring period, 16.5% of those with mild Alzheimer’s disease died. Consumption of 2-3 units of alcohol every day was associated with a 77% lowered risk of death compared with consumption of 1 or fewer daily units. There was no significant difference in death rates among those drinking no alcohol or more than 3 units every day compared with those drinking 1 or fewer daily units. These results held true after taking account of influential factors: gender, age, other underlying conditions, whether the individual lived alone or with their primary carer, educational attainment, smoking, quality of life, and MMSE result.
The researchers say there could be several explanations for the findings, including that people who drink moderately have a richer social network, which has been linked to improved quality, and possibly length, of life. Another explanation may lie in the fact that the seemingly protective effect of alcohol may have been caused by reverse causality, whereby those drinking very little alcohol were in the terminal phase of their life, which would have artificially inflated the positive association. In a bid to correct for this, the researchers re-analysed the data, omitting the first year of monitoring. But this made no difference to the findings.
The study finds that in this cohort of patients with mild AD, moderate alcohol consumption (2–3 units/day) was associated with a significantly lower mortality over a period of 36 months. They suggest that further research looking at the impact of alcohol on cognitive decline and disease progression in patients with mild Alzheimer’s disease would be particularly informative.
Source: Alcohol consumption and mortality in patients with mild Alzheimer's disease: a prospective cohort study. Sine Berntsen, Jakob Kragstrup, Volkert Siersma, Gunhild Waldemar, Frans Boch Waldorff. BMJ Open 2015;5.