Alcohol consumption is indisputably harmful to the developing brain, but what about the aging brain? Researchers investigated the relationship between alcohol consumption in people with mild cognitive impairment and people who progress to dementia. The meta-analysis1, published in the journal of Aging Clinical and Experimental Research, shows an increased risk of dementia progression for heavy alcohol consumption, but no association for light to moderate drinking.
What is already known? There is reasonable scientific evidence that there is a J-shaped relationship between alcohol consumption and dementia. Some studies suggest a protective effect of light to moderate alcohol consumption on dementia2. Currently, it is not well understood how alcohol affects mild cognitive impairment, and if alcohol consumption in the mildly impaired can accelerate the development of dementia.
What does this study add? This study evaluates the relationship between alcohol consumption and the risk of mild cognitive impairment and subsequent progression to dementia for the first time using a systematic approach. The meta-analysis includes six prospective studies, resulting in around 4,200 participants.
Mild cognitive impairment
The authors found a linear relationship between alcohol consumption and mild cognitive impairment, which suggests that each additional drink per week is associated with an increased risk of 3.8%. But the association lacked robustness.
Progression to dementia
For the progression of dementia, the results show a non-linear relationship. Light and moderate alcohol consumption are not associated with an increased risk of progression to dementia. But heavy alcohol consumption (more than 14 drinks a week) is associated with a higher risk.
Previous studies were inconclusive about alcohol consumption and cognitive impairment. Some find a protective effect of alcohol on cognitive decline, but this result is not consistent among studies. Another study even showed that light to moderate drinking is a risk factor for the progression from cognitive impairment to dementia.
Since 5-10% of people with mild cognitive decline develop dementia, and no effective interventions exist, proper lifestyle choices are important to prevent further loss of cognition. Unfortunately, it is yet unclear if people with mild cognitive impairment should completely abstain from alcohol, which is partly caused by a lack of standardization to identify cognitive impairment.
- Dose-response analysis
- Studies performed in four different continents
- No analysis of publication bias
- Limited amounts of studies involved
- No distinction between alcoholic beverages
1 Lao, Y., Hou, L., Li, J., Hui, X., Yan, P., & Yang, K. (2020). Association between alcohol intake, mild cognitive impairment and progression to dementia: a dose–response meta-analysis. Aging Clinical and Experimental Research.
2 Wiegmann, C., Mick, I., Brandl, E. J., Heinz, A., & Gutwinski, S. (2020). Alcohol and Dementia – What is the Link? A Systematic Review. Neuropsychiatric Disease and Treatment, 16, 87–99.