Depression and vitamin D deficiency increase risk of young-onset dementia

The risk of young-onset dementia is higher in people with vitamin D deficiency, depression or diabetes, according to a new study.

Young-onset dementia refers to dementia developed before the age of 65, and is believed to affect 70,000 people in the UK.

The study, a collaboration between researchers at UK and Dutch universities, and published in Jama Neurology, looked at more than 350,000 participants in the UK biobank. Researchers carried out a baseline assessment between 2006 and 2010, and followed participants until March 2021. The study identified 15 factors that appeared to raise risk of young-onset dementia, including alcohol abuse, stroke, social isolation and hearing impairment. People who had been through higher education were less at risk.

Previous research has identified several genetic factors that can lead to young onset dementia. There has been less research, however, looking at the role of environmental and lifestyle factors in determining whether someone will develop the condition.

Opportunity to take action on risk factors

Professor David Llywellyn of the University of Exeter, one of the study’s authors, said: “This breakthrough study illustrates the crucial role of international collaboration and big data in advancing our understanding of dementia. There’s still much to learn in our ongoing mission to prevent, identify and treat dementia in all its forms in a more targeted way. This is the largest and most robust study of its kind ever conducted. Excitingly, for the first time it reveals that we may be able to take action to reduce risk of this debilitating condition, through targeting a range of different factors.”

Dr Stevie Hendriks, a researcher at Maastricht University in the Netherlands, said: “Young-onset dementia has a very serious impact, because the people affected usually still have a job, children and a busy life.

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

Four in 10 dementia cases linked to modifiable risk factors

The findings were welcomed by Dr Leah Mursaleen, the head of clinical research at Alzheimer’s Research UK, which co-funded the study. “We’re witnessing a transformation in understanding of dementia risk and, potentially, how to reduce it on both an individual and societal level,” she said. “In recent years, there’s been a growing consensus that dementia is linked to 12 specific modifiable risk factors such as smoking, blood pressure and hearing loss. It’s now accepted that up to four in 10 dementia cases worldwide are linked to these factors.

“This pioneering study shines important and much-needed light on factors that can influence the risk of young onset dementia, and starts to fill in an important gap in our knowledge. It will be important to build on these findings in broader studies.”

Sebastian Köhler, professor of neuroepidemiology at Maastricht University, said that previous research on older people had identified modifiable risk factors for dementia. He added: “In addition to physical factors, mental health also plays an important role, including avoiding chronic stress, loneliness and depression. The fact that this is also evident in young-onset dementia came as a surprise to me, and it may offer opportunities to reduce risk in this group too.”