Modern medicine has transformed our chances of surviving many of the diseases that once cut lives short, from heart disease and diabetes to many forms of cancer.
But dementia has proved a stubborn exception.
There is still no cure, few treatments that can slow its progress, and the number of people living with the disease is rising relentlessly.
And while it remains overwhelmingly a disease of old age, affecting nearly one in three Americans aged 85 and over, that is no longer the whole story.
A growing number of people are now being diagnosed in their 50s or even 40s – while they are still building careers, raising children and, in many cases, caring for ageing parents.
Many have yet to walk their children down the aisle or welcome grandchildren.
And unlike in older patients, the first signs of what is known as early-onset dementia are not always memory lapses.
Instead, the disease may first reveal itself through sudden personality changes, difficulty finding words, poor judgement or an unexpected struggle to cope with everyday tasks at work.
Jana Nelson was 50 when diagnosed with early onset dementia, following severe personality changes and a sharp cognitive decline that left her unable to solve simple math problems or name colors
With diagnoses of dementia in under-65s rising by as much as 200 percent between 2013 and 2017, researchers are racing to understand why.
Greater awareness of the condition may partly explain the rise. But mounting evidence suggests lifestyle factors – including obesity, smoking, diabetes and poor sleep – may also play a role, with the roots of the disease stretching back decades before symptoms first appear.
So what’s really driving this worrying surge, and what can you do to lower your risk? We asked the experts what is driving the trend – and what it means for you.
No longer just a disease of old age
Dementia is an umbrella term for a group of disorders that cause memory loss and a gradual decline in thinking and reasoning, with Alzheimer’s disease accounting for most cases.
The condition is caused by the build-up of abnormal proteins in the brain that gradually destroy nerve cells, particularly in areas responsible for memory, language and decision-making.
By far the biggest risk factor is age – after 65, the likelihood of developing dementia doubles every five years. But of the seven million Americans living with the condition, around 350,000 are under the age of 65, many of them in their 40s and 50s.
Speaking to the Daily Mail, Dr Dorothea Altschul, a neurosurgeon at Neurosurgeons of New Jersey says: ‘The underlying diseases can be the same ones we see in older adults, but the context is different.
‘Because of the age difference, these are often people who are still working, raising children, managing households and leading very active lives.’
And unlike in older adults, memory loss is not always the first warning sign.
‘Some younger patients first show changes in language, decision-making, problem-solving, behavior and personality,’ Dr Altschul says.
‘A spouse or coworker may notice that the person is no longer handling everyday tasks the same way, even before obvious memory problems appear.’
Because dementia is so unexpected in younger adults, those early symptoms can easily be dismissed as stress, burnout or simple absent-mindedness, delaying diagnosis.
That was the case for Idaho mother-of-two Jana Nelson, whose family initially noticed she had become unusually short-tempered and prone to dramatic mood swings in her late 40s.
As first revealed by the Daily Mail in 2024, it was only after she developed problems with balance and began repeating herself that an MRI revealed she had early-onset dementia at the age of 50.
Why cases of young dementia are rising
Experts expect the number of Americans living with dementia to double by 2050 as the population ages.
But younger adults are also accounting for a growing number of diagnoses.
A 2020 Blue Cross Blue Shield report found diagnoses of early-onset dementia among commercially insured Americans aged 30 to 64 rose by 200 percent between 2013 and 2017. The sharpest increases were seen in adults aged 30 to 44.
But experts believe greater awareness is also part of the story.
‘What I have noticed most is that younger people are becoming more willing to talk about cognitive changes and seek an evaluation,’ Dr Altschul says.
‘Years ago, someone might have dismissed symptoms for a very long time. Now, patients and their families are more likely to say, “This isn’t right. This is more than forgetfulness.”‘
Globally, the trend has also been reflected in research. A 2021 meta-analysis involving 2.7 million adults from more than 30 countries found early-onset dementia was more than twice as common as previous estimates had suggested.
Greater awareness may explain part of the increase. But researchers also believe lifestyle factors – including obesity, diabetes, smoking and poor sleep – could be contributing to a genuine rise in risk decades before symptoms first appear.
Rebecca Luna suffered early-onset Alzheimer’s, with symptoms appearing in her late 40s. She would black out mid-conversation, lose her keys and leave the stove before returning to find her kitchen full of smoke
The lifestyle factors driving the surge
Genetics explain some cases of early-onset dementia.
The strongest known genetic risk factor is the APOE4 gene, carried by between 40 and 65 percent of people with Alzheimer’s disease, the most common form of dementia.
Scientists believe APOE4 makes brain cells more vulnerable to damage, accelerating the toxic changes that drive Alzheimer’s disease. People who inherit one copy typically develop symptoms five to ten years earlier than those without the gene, while those with two copies may develop the first signs more than a decade earlier.
But genes are only part of the story, says Dr Altschul: ‘It’s hard to point to a singular, specific reason. Part of the increase may be due to better awareness and better diagnosis.
‘We are identifying cases that may have been missed in the past. But lifestyle and overall health will play a role as well.’
A groundbreaking 2024 review in The Lancet estimated that nearly half of dementia cases could be linked to 14 largely preventable risk factors.
Some – including high cholesterol, high blood pressure, diabetes, smoking and physical inactivity – damage the heart and blood vessels that supply the brain, increasing the risk of both Alzheimer’s disease and vascular dementia.
Others, such as obesity, excessive alcohol consumption, traumatic brain injury and air pollution, appear to fuel chronic inflammation and accelerate the build-up of the toxic amyloid and tau proteins associated with Alzheimer’s disease.
The remaining factors – hearing loss, vision loss, depression, social isolation and low educational attainment – are thought to reduce the brain’s ‘cognitive reserve’, leaving it less able to compensate for the damage caused by ageing and disease.
So what can you do to lower your risk? The answer is, quite a lot.
While dementia is irreversible, Dr Altschul explains that avoiding chronic health conditions like diabetes, obesity and high blood pressure can help prevent the disease in the first place.
‘For most patients, [dementia] is likely a combination of genetics, vascular health, lifestyle, and other factors rather than one clear cause,’ she said.
‘That can sound intimidating, but the positive side of that is that many of the risk factors we know about can be improved.
‘Staying physically active, managing blood pressure and diabetes, avoiding smoking, getting enough sleep, maintaining a healthy weight, treating hearing loss, staying socially connected and continuing to learn and challenge your brain are all things that will help.’
A recent study in the British Journal of Sports Medicine, for example, found that just two hours a week – or 17 minutes a day – of weightlifting was associated with a roughly 13 percent lower risk of dementia.
And researchers at Rutgers University found in a 2026 study that groups who practiced intermittent fasting and ate only between 10am and 6pm every day had improved spatial planning and memory scores compared to those who did not fast.
The ‘red flag’ signs you should never ignore
Dr Altschul said that in young people, the warning signs of early-onset dementia can start out subtly before progressing over time.
‘The difference between normal forgetfulness and something more concerning is something we should focus on. It’s very normal to forget a name or walk into a room and forget why we went into that room. That happens,’ she said.
‘The red flags are changes that are persistent, getting worse, or beginning to interfere with everyday life.
‘That might include getting lost in a familiar area, struggling with tasks that were once routine, having increasing difficulty finding words, making unusual decisions, or showing noticeable changes in personality or behavior.’
Rebecca Luna’s story illustrates just how devastating early-onset Alzheimer’s can be.
As reported by this news website, the Canadian single mother was just 46 when she began blacking out mid-conversation, losing her keys and forgetting she had left the stove on.
Wendy Williams announced her frontotemporal dementia diagnosis when she was just 59 in February 2024. She is pictured above in 2019
She later documented her diagnosis to more than 47,000 TikTok followers before choosing to end her life through Canada’s Medical Assistance in Dying (MAID) program last month, aged just 49.
The warning signs also vary depending on the type of dementia.
In frontotemporal dementia, for example, damage primarily centers on the brain’s frontal and temporal lobes, causing personality and judgment changes first. Younger patients may notice themselves becoming uncharacteristically impulsive or lacking a filter in conversations.
The condition thrust into the spotlight in 2024 after television host Wendy Williams revealed she had been diagnosed with frontotemporal dementia at the age of 59.
‘Sometimes the person experiencing the symptoms does not recognize the change as clearly as the people around them do,’ Dr Altschul says.
‘If a spouse, family member, or coworker repeatedly says they are noticing something different, that is when we should consider taking it seriously.’
Anyone experiencing memory or personality changes, no matter their age, should seek care immediately, she adds.
‘Most younger people with memory concerns will not turn out to have dementia,’ Dr Altschul says. ‘But they also should not assume they are too young for a neurological problem.
‘It is better to get evaluated and understand what is happening than ignore it.’