Prevention is Key to Management
That brings prevention and delaying the onset of dementia right into the foreground, although the role of lifestyle and cognitive ageing is very poorly understood. It’s well known that dementia has a very long “pre-clinical phase”, in which various biomarkers may change over a period of years[i]. This means that it may be possible to spot the signs of dementia long before any symptoms present.
However, the trials that are needed to prove or disprove any link are very long-term. So, although there are lots of pills and other interventions available today, it’s extremely problematic to prove definitively whether they are a miracle cure or just snake oil.
Robust Trials Are Tricky
Really getting to grips with the impact of different lifestyle choices or behaviours on ageing, particularly age-related cognitive function, is an incredibly challenging process. Biases, where results can be skewed by perceptions or other factors, are often linked with studies that rely on self-reporting. As it’s very difficult to monitor large groups of adults over an extended period, it’s understandable that self-reported studies are the most common form of evaluation.
However, very long-term studies can mitigate these risks somewhat, because careful meta-analysis of long-term data can reduce the impact of selection biases (those who already drink to excess and smoke are more likely to die before any study of elderly people begins) and other problems in constructing the studies.
Alcohol and Cognitive Decline
Now, in some of the most recent research[v] into alcohol consumption and cognitive function, the picture becomes even more complicated.
There is much data to suggest that both abstinence and over-consumption of alcohol have a negative impact on cognitive ageing. This position may seem contradictory, in that most people would expect trials to clearly show that one or other approach to alcohol consumption would take precedence. However, the same relationship can also be observed in body weight, where being over-weight or under-weight can both cause serious health problems.
To date, most of the studies looking at the relationship between alcohol and age have focussed on senior citizens. However, as many people reduce the amount of alcohol they consume as they age, the consumption recorded in these studies often does not accurately reflect past practises, which could (in the same way smoking can) have serious effects on long-term cognitive ageing.
In one notable report recently published in the BMJ, the researchers used many different data points to tell between those who had been tee total for many years and those that had a more recent reduction in alcohol consumption. The researchers found marked changes in cognitive risk profiles among long-term abstainers, ex-drinkers and occasional drinkers.
After looking at the data more closely, the team found that some increase in the risk of cognitive decline related to alcohol consumption was explained by other health indicators, such as cardiac and metabolic health profiles.
Can Drinking Prevent Cognitive Decline?
To date, it’s unclear whether the impact of potential selection bias on previous studies, or the seemingly positive impact of alcohol consumption on cognitive ageing in moderate drinkers, is really the true and complete picture.
Further research, which doesn’t rely on self-reported alcohol consumption, is needed to definitively prove the true association between alcohol consumption and cognitive health.
However, with existing research (like the "Whitehall II study") clearly showing that heavy drinking increases the risk of dementia in later life, it’s undeniable that some types of alcohol consumption do have a detrimental overall effect on cognitive health.
Steps to Protect Your Cognitive Health
Given the long lead time of dementia developing and the tell-tale signs of cognitive decline, often visible over many years, it’s hugely important that the role of modifiable risks (like alcohol consumption) and health behaviours are better understood.
Unfortunately, good science can take years to show clear results, which is time many people don’t have. Taking steps now, such as moderating alcohol consumption, is probably the best step towards protecting long-term cognitive health.
Cognitive Health Check is an independent source of information and news about cognitive health.