Major study links 15 factors to risk of early-onset dementia: ScienceAlert

Although dementia is much more common in older adults, hundreds of thousands of people are diagnosed with young-onset dementia (YOD) each year, and a comprehensive study published in 2023 sheds considerable light on why.

Most previous research in this area has focused on genetics passed down through generations, but here the team was able to identify 15 different lifestyle and health factors associated with YOD risk.

“This is the largest and most robust study of its type ever carried out,” said epidemiologist David Llewellyn of the University of Exeter in the United Kingdom, when the results were published in December. 2023.

“Excitingly, this reveals for the first time that we may be able to take steps to reduce the risk of this debilitating disease, by targeting a range of different factors.

The research team analyzed data collected from 356,052 people aged under 65 in the UK.

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 meant higher risk, as did the presence of two variants of the ApoE4 ε4 gene (a genetic scenario already linked to Alzheimer’s disease).

Researchers have described the relationship between alcohol and YOD as “complex.”

While heavy drinking carries increased risk, moderate to heavy drinking correlates with reduced risk – perhaps because people in this second group are generally healthier overall (keep in mind that those who abstain from alcohol often do so for medical reasons).

Higher levels of formal education and lower physical frailty (measured by higher grip strength) were also associated with lower YOD risk. All of this helps fill some of the knowledge gaps around YOD.

“We already knew from research on people with dementia in old age that there are a range of modifiable risk factors,” said neuroepidemiologist Sebastian Köhler of Maastricht University in the Netherlands.

“In addition to physical factors, mental health also plays an important role, including avoiding chronic stress, loneliness and depression.”

Although the findings do not prove that dementia is caused by these factors, they help paint a more detailed picture. As always in this type of research, learning more about the causes can help develop better treatments and preventative measures.

Many of these factors are modifiable, providing more hope for those striving to find ways to beat dementia rather than just manage it.

Ultimately, we may be able to reduce the risk of dementia by living healthier lives.

“Early-onset dementia has a very serious impact, because those affected usually still have jobs, children and busy lives,” said neuroscientist Stevie Hendriks, from Maastricht University.

“It’s often assumed that the cause is genetic, but for many people we don’t know exactly what the cause is. That’s why we also wanted to investigate other risk factors in this study.”

The research was published in JAMA Neurology.

A version of this article was first published in January 2024.