Cognitive decline is defined as the reduction in one or more cognitive abilities, such as memory, awareness, judgement and mental acuity. When the decline crosses a specific threshold and compromises social or occupational functioning, it becomes dementia.
Dementia or cognitive decline is a major issue. It not only affects your ability to carry out your day to day tasks effectively, but can often accelerate other diseases, increase the risk of frailty and falls and reduce lifespan. Apart from what it does to you, there is a high burden imposed on those around you and your caregivers.
There are four issues here.
Can we prevent cognitive decline?
Can we arrest cognitive decline or reduce its rate of decline, once it occurs?
What is the impact of social isolation and loneliness?
Should we test for cognitive decline?
Can we prevent cognitive decline?
The same factors that increase healthspan and lifespan also prevent or push back cognitive decline. The CHAP study [1] evaluated people over the age of 65, from a geographically defined community in Chicago. Between 1993 and 2012, 10802 people were enrolled. 2449 people from this cohort were eligible for this particular assessment.
The study looked at 5 factors.
Adherence to a Mediterranean-DASH (Dietary Approaches to Stop Hypertension) / MIND Diet Intervention for Neurodegenerative Delay (MIND) diet
Late life cognitive activities such as reading, playing cards, solving puzzles, etc
Physical activity (PA) - healthy PA was defined as greater than 150 minutes of moderate PA per week
Non-smokers, both reformed and never-smokers.
No or light to moderate alcohol consumption (1-15 g/day in women and 1-30 g/day in men).
The results were astounding.
Women above the age of 65 who met 4 or 5 of these health criteria had a live expectancy of 24.2 years (22.8 to 25.5) and lived 3.1 years longer than those with 1 or none of these factors (life expectancy - 21.1 years - 19.5 to 22.4). More importantly, the women with healthy habits (4/5 or 5/5) remained Alzheimer’s free for 89.2% of that life expectancy (21.6 years lived without dementia of those 24.2 years), while the women with an unhealthy lifestyle (0/5 or 1/5) were dementia free for only 80.7% of their remaining years (i.e. 17 years out of their life expectancy of 21.1 years).
It was the same for men. Men with a healthy lifestyle (4/5 or 5/5) lived 23.1 years beyond the age of 65 (21.4 to 24.6) as compared to the unhealthy men (0/5 or 1/5) who had a life expectancy of only 17.4 years (15.8 to 20.1). The healthy men lived 94.9% of their remaining lifespan over 65, dementia free (21.7 years without dementia) compared to the unhealthy men who lived only 88% of their lives dementia free (15.3 years).
So effectively, women with a healthy lifestyle lived 3.1 years longer than women with an unhealthy lifestyle, while with men, the difference was even more at 5.7 years. The same was true of the number of years lived without dementia.
What all this means is that the healthier you are, the more the chances that you can prevent or push back cognitive decline and dementia.
Can we arrest cognitive decline or reduce its rate of decline, once it occurs?
Cognitive reserve is defined as the resilience developed by some people in staving off the effects of dementia, even if their brains at autopsy or on MRI show the same degeneration as those who have functional dementia. Those who have higher cognitive reserve somehow develop alternate functional pathways in those parts of the brain that are damaged by dementia producing disease. The main factor that influences the extent of cognitive reserve is the extent of education. “Individuals with increased cognitive reserve tend to be more highly educated, possess higher IQs, reach higher occupational attainment, and are involved in a diverse range of leisurely activities.” [2].
Not only that, as the NUN study [3] showed, cognitive decline is reversible and in many instances may never progress to dementia. The higher the levels of education, the higher the reversibility and the lower the risk of dementia.
Life-long learning also increases cognitive reserve and staves off cognitive decline as the Rush University study [1] showed. Those who maintain higher levels of cognitive activity can push back dementia by almost 5 years compared to those with lower levels. These “cognitive” activities include reading, writing and playing games such as puzzles, cards, etc.
Irrespective of your education level therefore, it is therefore a good idea to start structured learning and to cultivate a wide range of leisure activities and hobbies that involve reading and learning and then try and implement that knowledge gained, in the best possible way.
What about loneliness and social isolation?
Loneliness and social isolation accelerate cognitive decline.
As Baz Luhrman says in the middle of his song, “Everybody is Free to Wear Sunscreen”.
Get to know your parents, you never know when they'll be gone for good
Be nice to your siblings, they're your best link to your past
And the people most likely to stick with you in the future
Understand that friends come and go
But with a precious few, you should hold on
Work hard to bridge the gaps in geography and lifestyle
For as the older you get
The more you need the people you knew when you were young
Cultivating relationships with a spouse, with friends and family makes a difference. This allows us to connect with people, to share our thoughts and feelings and to spend time with them, with the confidence and understanding that they also have our backs as we have theirs. The poets, writers, philosophers have gotten it right for more than two millennia…we now have objective data as well. Those who are lonely get dementia early.
Should we test for cognitive decline?
Should we test for minimal cognitive impairment (MCI), so that we can perhaps double-down on our efforts to reduce or control the decline, if we test positive? If you have no symptoms, or if you just tend to forget names and car-keys, but are otherwise fine, it probably does not help to get tested, especially now that we know that MCI can spontaneously reverse.
However, if others around you start noticing that you are finding it difficult to carry out daily activities, then testing and evaluation by a professional may help to understand the extent of cognitive decline and to institute measures to prevent harm to yourself and those around you.
What does this mean for you and I in our quest for a long healthspan.
It is possible to prevent or push back cognitive decline and dementia with sensible eating, physical activity, not smoking, none to minimal alcohol consumption and engaging in cognitive activities.
The higher the cognitive reserve, which typically is linked to the level of education, the better the chance that minimal cognitive decline may be reversible and/or that dementia may be pushed back or staved off.
The more you cultivate habits that allow learning and intellectual stimulation, the more is the likelihood of being dementia free.
The older you get, the more important it is to maintain relationships with your near and dear ones, to reduce the chance of dementia.
Footnotes
1. Dhana K et al. BMJ. 2022 Apr 13;377:e068390.
2. Pengpid S et al. Geriatric Psychiatry 2021;36:1722
3. Iraniparast M et al. Neurology. 2022 Mar 15;98(11):e1114-e1123.
Dr. Bhavin Jankharia’s new book “Atmasvasth” available online, dives deeper into this concept. He can provide references for all statements of fact and can be reached at bhavin.mm@gmail.com