Although dementia is more prevalent among older people, hundreds of thousands of people are diagnosed with early-onset dementia (YOD) each year, and a large-scale study has shed some light on why.
Most previous research in this area has focused on genetics that are passed down through generations, but in this study, the team was able to identify 15 different lifestyle and health factors associated with YOD risk.
“This is the largest and most thorough study of its kind ever conducted,” David Llewellyn, an epidemiologist at the University of Exeter in the UK, said when the results were published in December.
“The exciting news is that for the first time, we now know that by targeting a range of factors, we may be able to take steps to reduce the risk of this debilitating disease.”
The research team analysed data collected from 356,052 people in the UK under the age of 65. Low socioeconomic status, social isolation, hearing loss, stroke, diabetes, heart disease and depression were all associated with a higher risk of YOD.
Vitamin D deficiency and high levels of C-reactive protein (produced by the liver in response to inflammation) also mean you’re at higher risk, as does having two copies of the ApoE4 ε4 gene variant (a genetic scenario already linked to Alzheimer’s).
The researchers described the relationship between alcohol and YOD as “complex.” Alcohol abuse was linked to increased risk, while moderate to heavy drinking was correlated with decreased risk, likely because this second group of people is generally healthier (note that people who abstain from alcohol often do so for medical reasons).
Higher levels of formal education and lower levels of physical frailty (measured by higher grip strength) were also associated with lower YOD risk, all of which help fill gaps in our knowledge about YOD.
“We already knew from studies of people who develop dementia later in life that there are a series of modifiable risk factors,” said Sebastian Koehler, a neuroepidemiologist at Maastricht University in the Netherlands.
“In addition to physical factors, mental health also plays an important role, including avoiding chronic stress, loneliness and depression.”
The results don’t prove that dementia is caused by these factors, but they help paint a more detailed picture. As is always the case with this type of study, knowing more about causes can help develop better treatments and prevention strategies.
Many of these factors are modifiable, offering more hope to people trying to find ways to not only manage but overcome dementia. After all, dementia may be something you can reduce your risk of by living a healthier lifestyle.
“Early-onset dementia has a very devastating impact because those affected usually have jobs, children and lead busy lives,” said Stevie Hendrix, a neuroscientist at Maastricht University.
“It’s often thought that the cause is genetic, but for many people we don’t know exactly what causes it, so in this study we wanted to look at other risk factors as well.”
The study was published in JAMA Neurology.
A version of this article was first published in January 2024.
