The Mystery Of Cognitive Decline: Why Only Some People Age Gracefully

From education to cognitive reserve, discover the key factors that slow down cognitive decline as we age.

From education to cognitive reserve, discover the key factors that slow down cognitive decline as we age.

Why do some people’s cognitive skills glide down a gentle slope as they age while others fall of a cliff?

Living healthily — eating right and getting enough exercise — are certainly important, but they don’t explain the whole picture.

In fact, many of the factors we think of as being vital to aging gracefully have relatively little effect, research finds.

Lifestyle factors like avoiding smoking, taking vigorous exercise and weight control explain only about 38 percent of the variation in cognitive functioning by the time people reach their mid-50s.

And between the ages of 54 and 85, these lifestyle factors only account for a measly 6 percent of the variation in how quickly people decline cognitively.

So what about the rest? Could that all be down to genetics and therefore something we can do nothing about?

Dr Hui Zheng, the study’s first author, is not sure either:

“There’s still a lot we don’t know about why cognitive functioning varies so much between older adults.

More research is urgently needed to discover the main causes of how quickly cognitive functioning declines and how we can slow down its progression.”

Education is top factor

For the study, researchers used data from over 7,000 people whose cognitive functioning was tracked until they were 85-years-old.

The results showed that education was the single largest factor in explaining people’s cognitive decline up to the age of 54 (25 percent).

People with more education, then, retained greater thinking skills with age.

After this, race, parental education, depression, occupation, and household wealth had relatively little effect, as did marital status, religion, gender, health behaviours and chronic diseases.

In contrast, all these factors had relatively little effect between 54 and 85.

This suggests it is much better to start change earlier, said Dr Zheng:

“From an intervention perspective, that suggests it is much more important to try to improve functioning at the baseline than trying to slow down the rate of decline.”

Cognitive reserve

The beneficial effect of education in maintaining thinking skills supports the ‘cognitive reserve hypothesis’.

This is the idea that people who build up cognitive reserves early on are better able to withstand the degrading effects of age or brain damage.

It is rather like a runner who is capable of running faster than they habitually do, so that when age slows their maximum, they can still use that extra bit of performance.

Dr Zheng said:

“College may provide an especially rich environment for cognitive development that may help people develop this cognitive reserve.”

What about genetics?

This study did not include genetic factors, but other research has suggested that 41 percent of cognitive decline is down to genetics.

That still leaves much to be explained.

Dr Zheng said:

“Cognitive decline is pervasive in older adults, even those without dementia, which is why it is important to study other predictors of cognitive functioning and decline.

But still, our study raises more questions than it answers.

We have a long way to go to understand the trajectories of cognitive functioning in older adults.”

The study was published in the journal PLoS ONE (Zheng et al., 2023).

The Personality Trait Linked To Dementia

At least 5 million Americans are living with Alzheimer’s.

At least 5 million Americans are living with Alzheimer’s.

Having moderate or severe anxiety in midlife is linked to dementia later on, research finds.

Anxiety is strongly linked to the personality trait of neuroticism, which includes sadness, irritability and self-consciousness.

The extra risk could be related to the stress caused by a mental health condition.

The stress response to anxiety could accelerate the aging process in the brain, increasing cognitive decline.

Depression has already been linked to a doubling of the risk in developing dementia.

Tackling anxiety and depression in midlife could be a way to reduce dementia risk, the study’s authors write:

“Non-pharmacological therapies, including talking therapies, mindfulness-based interventions, and meditation practices, that are known to reduce anxiety in midlife, could have a risk-reducing effect, although this is yet to be thoroughly researched.”

The study was a meta-analysis, a type of research that pools together the results of other studies.

The researchers found four large studies examining the link between dementia and anxiety that together included almost 30,000 people.

All four studies found that moderate to severe anxiety was linked to developing dementia later on.

The researchers write:

“Clinically significant anxiety in midlife was associated with an increased risk of dementia over an interval of at least 10 years.”

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:

“Mental health conditions like anxiety and depression have been linked to dementia before and many overlapping symptoms make a dementia diagnosis difficult.

This review took a high-quality approach, combining findings from four existing studies exploring anxiety as a risk factor for dementia.


It’s important to remember that just because there is an association between the two factors does not necessarily mean that anxiety causes dementia.

Dementia is caused by a complex mix of risk factors including age and genetics and although this study looked at dementia in people more than ten years after being diagnosed with anxiety, we know the diseases leading to dementia can begin in the brain up to twenty years before any symptoms show.”

The study was published in the journal BMJ Open (Gimson et al., 2018).

This Drink May Cut Dementia Risk In Half

It can help clear the brain of toxins.

It can help clear the brain of toxins.

Drinking moderate amounts of alcohol is linked to a 45% lower risk of dementia, research concludes.

Moderate drinkers — those who drink no more than around a bottle and half of wine a week — saw the reduced risk in comparison to those who do not drink.

Moderate drinkers also had a lower risk of dementia than those who drank heavily.

As alcohol intake increases, so does the risk of dementia.

A couple of alcoholic drinks per day, though, can help clear the brain of toxins, some research finds.

Low levels of alcohol — the equivalent of around 2.5 standard drinks per day — may help to remove waste linked to Alzheimer’s disease and reduce inflammation in the brain.

The study’s authors write:

“We show that both long term alcohol abstinence and excessive alcohol consumption may increase the risk of dementia.

Given the number of people living with dementia is expected to triple by 2050 and the absence of a cure, prevention is key.”

The study’s conclusions come from an analysis of 9,087 people who were followed for around 23 years between 1985 and 1993.

Dr Sevil Yasar, writing in a linked editorial, said:

“The most intriguing finding from this study was the significantly increased risk of dementia among abstainers, including long term abstainers and participants who became abstainers, and that association was only present in those who abstained from wine.”

Dr Yasar continued:

“Wine, in addition to alcohol, contains polyphenolic compounds, which have been associated with neuroprotective effects on both neurodegenerative and vascular pathways, and with cardioprotective effects through inflammation reduction, inhibition of platelet aggregation, and alteration of lipid profile.”

One limitation of the study is that people who abstain from alcohol may have a history of overindulgence.

Along with the study design, this makes it difficult to draw firm conclusions about causality.

The study was published in the BMJ (Sabia et al., 2018).

The Common Food That Shrinks Your Brain

The food that shrinks your brain and leads to dementia.

The food that shrinks your brain and leads to dementia.

The average person eats the equivalent of an extra burger meal every day compared with 50 years ago, research finds.

A burger, fries and soft drink works out to an extra 650 calories per day.

That is around 30 percent more calories than people need.

The consequences for people’s waistlines and their brains is devastating.

Brain health declines dramatically as a result of poor nutrition, especially early in life.

One of the main culprits is sugar, which accelerates neurodegeneration and impairs cognitive function.

People need to eat well and exercise early in life to avoid brain shrinkage and dementia later on.

Professor Nicolas Cherbuin, the study’s first author, said:

“People are eating away at their brain with a really bad fast-food diet and little-to-no exercise.

We’ve found strong evidence that people’s unhealthy eating habits and lack of exercise for sustained periods of time puts them at serious risk of developing type 2 diabetes and significant declines in brain function, such as dementia and brain shrinkage.”

The conclusions come from a review of around 200 studies carried out around the world.

Fully 30 percent of the world’s population is obese now, and 10 percent will have type 2 diabetes by 2030.

Professor Cherbuin said:

“The link between type 2 diabetes and the rapid deterioration of brain function is already well established.

But our work shows that neurodegeneration, or the loss and function of neurons, sets in much, much earlier—we’ve found a clear association between this brain deterioration and unhealthy lifestyle choices.

The damage done is pretty much irreversible once a person reaches midlife, so we urge everyone to eat healthy and get in shape as early as possible—preferably in childhood but certainly by early adulthood.”

The effort to improve diet is coming too late for many, said Professor Cherbuin:

“What has become really apparent in our investigation is that advice for people to reduce their risk of brain problems, including their risk of getting dementia, is most commonly given in their 60s or later, when the ‘timely prevention’ horse has already bolted.

Many people who have dementia and other signs of cognitive dysfunction, including shrinking brains, have increased their risk throughout life by eating too much bad food and not exercising enough.

One of the best chances people have of avoiding preventable brain problems down the track is to eat well and exercise from a young age.

The message is simple, but bringing about positive change will be a big challenge.

Individuals, parents, medical professionals and governments all have an important role to play.”

The study was published in the journal Frontiers in Neuroendocrinology (Cherbuin & Walsh, 2019).

This Change In Personality Indicates Dementia

Older people given personality tests were followed for many years to see who developed dementia.

Older people given personality tests were followed for many years to see who developed dementia.

Increases in the personality trait of neuroticism are a sign that someone will go on to develop dementia, research finds.

Neuroticism is a personality trait that is strongly linked to anxiety, sadness, irritability and self-consciousness.

People higher in neuroticism find it harder to deal with stress and tend to see threats everywhere.

The conclusions come from analysis of data from almost two thousand people in the US and the Netherlands.

Older people given personality tests were followed for many years to see who developed dementia.

The study’s authors explain:

“These findings provide reliable evidence of a consistent pattern of neuroticism increases preceding dementia diagnosis, and, further, suggest that change in neuroticism may occur early in the disease process.

Additionally, these results indicate that individuals who remain undiagnosed have markedly different trajectories of neuroticism compared to individuals not diagnosed with incident dementia or MCI [mild cognitive impairment].”

Along with increasing neuroticism, the researchers also found that people who went on to be diagnosed with dementia also saw decreases in extraversion.

They write:

“Assessments of extraversion, conscientiousness, openness and agreeableness were also available…

Our analyses revealed significant decreases in extraversion only, and solely for individuals with MCI [mild cognitive impairment].

These results may indicate that individuals with MCI might feel more cognitively challenged in the presence of others, possibly leading to avoidance of social activity.”

The study was published in the The Journals of Gerontology (Yoneda et al., 2018).

The Best Lifestyle Change To Prevent Cognitive Decline

It takes 20-30 years for the brain changes leading to Alzheimer’s to occur.

It takes 20-30 years for the brain changes leading to Alzheimer’s to occur.

The very best lifestyle change a person can make in midlife to protect against cognitive decline later is taking more exercise.

The results come from a study of 387 women in Australia who were followed from 1992 when they were between 45 and 55-years-old.

They were followed for over 20 years.

The researchers recorded all sorts of lifestyle factors including:

  • mood,
  • smoking,
  • marital and employment status,
  • education,
  • and diet.

Each person was given simple tests of memory, such as the ability to remember a list of ten unrelated items.

Dr Cassandra Szoeke, who led the study, said:

“We now know that brain changes associated with dementia take 20 to 30 years to develop.

The evolution of cognitive decline is slow and steady, so we needed to study people over a long time period.

We used a verbal memory test because that’s one of the first things to decline when you develop Alzheimer’s Disease.”

Out of all the lifestyle changes, the number one protective factor was exercise.

It didn’t matter what type — from walking the dog to climbing a mountain — exercise was the lifestyle factor that provided the greatest protective effect against memory loss.

Dr Szoeke said:

“The message from our study is very simple.

Do more physical activity, it doesn’t matter what, just move more and more often.

It helps your heart, your body and prevents obesity and diabetes and now we know it can help your brain.

It could even be something as simple as going for a walk, we weren’t restrictive in our study about what type.”

You should start as early as possible, Dr Szoeke said:

“We expected it was the healthy habits later in life that would make a difference but we were surprised to find that the effect of exercise was cumulative.

So every one of those 20 years mattered.

If you don’t start at 40, you could miss one or two decades of improvement to your cognition because every bit helps.

That said, even once you’re 50 you can make up for lost time.”

The study was published in the American Journal of Geriatric Psychiatry (Szoeke et al., 2016).

Medication Taken By 1 in 10 May Increase Dementia Risk 79% (M)

Almost one-in-ten regularly take this medication that is repeatedly linked to increased dementia risk.

Almost one-in-ten regularly take this medication that is repeatedly linked to increased dementia risk.

Another study has found a link between taking sleeping medication and increased dementia risk.

Taking sleep medication was linked to a 79 percent increased risk of dementia among white people.

The link was not seen in Black people, however, and Dr Yue Leng, the study’s first author, is not sure of the reason:

“Differences may be attributed to socio-economic status.

Black participants who have access to sleep medications might be a select group with high socio-economic status and, thus, greater cognitive reserve, making them less susceptible to dementia.

It’s also possible that some sleep medications were associated with a higher risk of dementia than others.”

The study included around 3,000 older people, average age 74, almost half of whom were Black.

The results showed that white people were three times as likely to take sleep medication as Black people.

White people were twice as likely to use benzodiazepines, like Halcion, Dalmane and Restoril and 7 times as likely to use “Z-drugs,” such as Ambien.

It may be that the types of drugs that white people take puts them at higher risk of dementia.

Alternatives to medication

For sleep problems, other options than medication should be considered, said Dr Leng:

“The first step is to determine what kind of sleep issues patients are dealing with.

A sleep test may be required if sleep apnea is a possibility.

If insomnia is diagnosed, cognitive-behavioral therapy for insomnia (CBT-i) is the first-line treatment.

If medication is to be used, melatonin might be a safer option, but we need more evidence to understand its long-term impact on health.”

The most common signs of sleep apnea, which affects 30 percent of older people, include:

  • Loud snoring,
  • gasping for air during sleep,
  • breathing stopping for brief periods during the night,
  • morning headache,
  • and daytime sleepiness and irritability.

Sleep and dementia

Poor sleep is one of the common symptoms of dementia, so it may be that taking more sleep medications is a result rather than a cause of dementia.

However, other studies have controlled for this factor and still found a link between anti-anxiety and sleep medication and early death.

These find a dose-response effect: the more of the drugs people took, the higher their risk of death.

Many other studies have found a link between dementia and sleep.

People who sleep for too little or too long are at a higher risk of cognitive decline and dementia.

Indeed, people who sleep more than 9 hours a night have double the risk of developing dementia, one study found.

However, those who sleep for between 5.5 and 7.5 hours per night do not see declines in their cognitive health, even when suffering the early effects of Alzheimer’s disease.

Those sleeping longer also have lower brain volumes.

Also, getting less REM sleep — the phase in which we dream — is linked to dementia.

→ Read on: Dementia: 9 Warning Signs Everyone Should Know

The study was published in the Journal of Alzheimer’s Disease (Leng et al., 2023).

A High Salt Diet Is Linked To Cognitive Decline

90% use too much salt and that can cause inflammation of blood vessels in the brain, which is linked to dementia.

90% use too much salt and that can cause inflammation of blood vessels in the brain, which is linked to dementia.

A high-salt diet is linked to cognitive decline and possibly dementia, research finds.

Salt causes the delicate lining of the brain’s blood vessels to inflame, because of signals sent from the gut.

Fully 90% of Americans consume above the recommended dietary maximum of 2,300 mg per day.

Dr Costantino Iadecola, study co-author, said:

“We discovered that mice fed a high-salt diet developed dementia even when blood pressure did not rise.

This was surprising since, in humans, the deleterious effects of salt on cognition were attributed to hypertension.”

The effect was quickly reversed by lowering salt intake.

The conclusions come from a study in which mice were fed a high-salt diet that is equivalent to a high-salt diet in humans.

Subsequently, the mice had much worse cognitive function.

Their brains showed 28% less activity in the cortex and 25% less in the hippocampus.

They had problems getting around a maze and did not show the usual interest in new objects placed in their cage.

They also had poorer blood flow in their brains and the integrity of the blood vessels there was worse.

However, these changes were reversed once the mice were returned to a normal diet.

The scientists found that these changes had nothing to do with higher blood pressure.

Worse cognitive functioning in the mice was seen even when the mice had normal blood pressure.

They were the result of signals sent from the gut to the brain.

These activated an immune response in the brain which increased levels of interleukin-17.

This eventually resulted in the inflammation of the delicate lining of the brain’s blood vessels.

The study was published in the journal Nature Neuroscience (Faraco et al., 2018).

The Popular Supplement That Fights Alzheimer’s

Around 1 in 6 people over 70 have mild cognitive impairment. About half of these people will go on to develop Alzheimer’s within five years.

Around 1 in 6 people over 70 have mild cognitive impairment. About half of these people will go on to develop Alzheimer’s within five years.

Alzheimer’s patients given omega-3 supplements retain their memory function, a small study has found.

Eighteen patients with the debilitating disease were given the omega-3 supplements morning and night for six months.

In total, patients had 2.3 g of omega-3 supplements each day.

They were compared to a group of 15 who acted as a control.

Dr Yvonne Freund-Levi, study co-author, explained the results:

“We can see that the memory function of the patients in the group that had taken omega-3 is stable, whereas the patients in the control group have deteriorated.

That’s what the memory tests show.”

The researchers also looked at biological markers in the patients’ spinal fluid.

This however, did not produce a difference between the two groups, said Dr Freund-Levi:

“…we can’t see any differences between the groups when we look at the various biomarkers in the spinal fluid samples.”

This small study is part of a larger programme looking at over 200 patients with mild to moderate Alzheimer’s disease.

They have so far found that omega-3 does transfer from the supplements to the brain.

In the present study, they also found that omega-3 was linked to biomarkers related to damaged nerve cells.

Dr Freund-Levi said:

“Even if this data isn’t enough for us to change our recommendations to patients at this time, it is an interesting material for researchers to build on.”

As this is a small study, it is wise to be cautious, said Dr Freund-Levi:

“We are cautious about giving recommendations, but we know that starting early is by far the best thing – it is difficult to influence the disease at a later stage.

The best piece of advice we have to offer at the moment is to be physically active and to include omega-3 in your diet – in the form of oily fish or as supplements.”

The study was published in the Journal of Alzheimer’s Disease (Tofiq et al., 2021).

Boost Memory: 10 Psychology Studies To Know

Boosts in all types of memory come from these simple activities.

Boosts in all types of memory come from these simple activities.

1. Draw it

Drawing pictures of words helps build stronger and more reliable memories, research finds.

The quality of the drawings themselves does not matter, the study also found.

This suggests everyone can benefit from the technique, whatever their artistic talent.

2. Close your eyes

Closing your eyes really can help jog the memory, a study finds.

Eyewitness to a crime remembered twice as many details using this technique.

The results should be useful for helping eyewitnesses to crimes remember more details when questioned by police.

3. Imagine how it relates to you

Imagining how things relate to yourself helps to boost recall, psychological research finds.

The study tested people with and without memory problems and found it could help both.

The results showed that whether people had memory problems or not, self-imagining was the most effective strategy.

Compared with the baseline condition, the self-imagining strategy almost tripled what people could remember.

4. 40 seconds rehearsal

Rehearsing a memory for just 40 seconds could be the key to permanent recall, a study finds.

When rehearsing a memory, the same area of the brain is activated as when laying it down, psychologists found.

This brain region — the posterior cingulate — is also the part that is damaged in Alzheimer’s disease.

Brain scans revealed that the more the activity matched when watching and rehearsing, the more people could remember.

5. Run barefoot

Running barefoot improves memory more than running with shoes on, a study finds.

The benefits may come from the extra demands placed on the brain while barefoot running.

For example, you have to avoid stones and anything else that may damage your feet.

The type of memory tested in the study is called ‘working memory’.

The brain uses working memory to recall and process information.

6. Handwrite it

Writing by hand strengthens memory in comparison to writing on a real or virtual keyboard, research finds.

The motor feedback from the process of writing along with the sense of touching paper and pen helps people learn.

Areas of the brain vital to language are more strongly activated by the physical activity.

7. Lift weights

One single workout with weights can immediately enhance long-term memory by around 20%, according to a study.

While it’s now well-established that months of aerobic exercise can enhance memory, this is the first study examining the effects of a relatively short amount of resistance training.

The reason this works is that exercise puts us into a heightened state, after which, memories — especially emotional ones — are more likely to stick.

8, 9 & 10. Childhood activities

Climbing a tree can improve working memory by 50%, a study finds.

The same is true of other dynamic activities like balancing on a beam, carrying awkward weights and navigating around obstacles.

Dr Tracy Alloway, one of the study’s authors, said:

“Improving working memory can have a beneficial effect on so many areas in our life, and it’s exciting to see that proprioceptive activities can enhance it in such a short period of time.”