With dementia predicted to affect 13.9 million adults in the United States by 2060, understanding why these conditions develop is more urgent than ever.
Scientists have uncovered certain factors that increase the risk of developing dementia. Some, such as advancing age, cannot be prevented. However, it is possible to avoid other potential risk factors, such as smoking tobacco.
It is essential to identify modifiable risk factors as understanding these could help prevent or delay the onset of dementia.
What do we already know?
Although some studies have investigated alcohol and dementia more broadly, there are still substantial gaps in our understanding. For instance, in an earlier study, researchers calculated alcohol consumption as a daily average across each year.
Using a daily average in this way misses the nuances of alcohol quantity and frequency.
This is an important point. For example, drinking 7 glasses of beer on 1 day each week is likely to have a different impact than drinking 1 glass of beer each night, every day of the week; although the quantity consumed is the same.
Other studies muddy the water further by looking at the links between alcohol, dementia risk, and the presence of apolipoprotein E4 (APOE E4). This gene variant has associations with an increased risk of developing Alzheimer’s.
An earlier study concluded that alcohol consumption increases the risk of dementia and that people with the APOE E4 variant have a higher chance of developing dementia.
Another unknown is how alcohol influences dementia risk for individuals with mild cognitive impairment (MCI). Scientists consider MCI to be the stage between normal age-related cognitive decline and dementia.
The current study set out to answer the questions above.
Alcohol and dementia data
To investigate, the scientists delved into an existing dataset, extracting the information from 3,021 participants, with an average age of 72.
The Ginkgo Evaluation of Memory Study from 2000–2008 supplied the data.
At the beginning of the study, participants provided information about the amount of alcohol they consumed, how often they drank, and what types of drinks they consumed — beer, wine, or liquor.
Scientists isolated DNA from blood samples to identify carriers of the APOE E4 variant.
Alongside genetic data and details about alcohol use, the scientists also collated information about blood pressure, body weight, height, history of heart disease, and smoking status. They also asked questions to estimate how regularly each participant was involved in social interactions.
Many gaps remain
Of the 3,021 participants, 2,548 did not have MCI, and 473 did have MCI. Over approximately 6 years of follow-up, 512 participants received a diagnosis of dementia.
When they analyzed the group of individuals with MCI, it was a similar story; there was no statistically significant difference.
However, dementia risk appeared to be highest for the individuals with MCI who drank 14 drinks per week compared with those who drank less than one drink each week — a relative risk increase of 72%.
“[D]aily low-quantity drinking was associated with lower dementia risk than infrequent higher-quantity drinking among participants without MCI at baseline.”