Up to 1.7 million people could be living with dementia in England and Wales by 2040—over 40% more than previously forecast—finds a new UCL-led study.

Previous studies, based on data up to 2010, showed that dementia incidence had declined in high-income countries. However, the new research, published in The Lancet Public Health, indicates that dementia incidence started to increase in England and Wales after 2008.

Based on this estimated upward incidence trend, researchers project that the number of people with dementia in England and Wales may be significantly higher than expected in the future.

According to previous research in England and Wales, the number of people living with dementia had been previously predicted to increase by 57% from 0.77 million in 2016 to 1.2 million in 2040.

However, the new research suggests that this figure could be as high as 1.7 million.

Researchers examined nine waves of data from people over the age of 50 and living in private households in England between 2002 and 2019, from the English Longitudinal Study of Aging (ELSA).

They found that the dementia incidence rate (a measure that considers the percentage of the population in each age group that has dementia) decreased by 28.8% between 2002 and 2008. However, it increased again by 25.2% between 2008 and 2016.

A similar non-linear pattern was observed across subgroups according to age, sex, and educational attainment.

Most notably, researchers found that disparities in the rate of dementia incidence were increasing between education groups, as there was both a slower decline in 2002-2008 and a faster increase after 2008 in participants with lower educational attainment.

If the incidence rate increases as fast as what was observed between 2008 to 2016 (a 2.8% increase per year) researchers predict that the number of people with dementia in England and Wales is set to increase to 1.7 million by 2040—approximately twice the number in 2023. This compares to an estimate of one million people if dementia rates had continued to decline as previously reported.

Lead author, Dr. Yuntao Chen (UCL Institute of Epidemiology & Health Care), said, "It is shocking to think that the number of people living with dementia by 2040 may be up to 70% higher than if dementia incidence had continued to decline.

"Not only will this have a devastating effect on the lives of those involved, but it will also put a considerably larger burden on health and social care than current forecasts predict.

"Continued monitoring of the incidence trend will be crucial in shaping social care policy."

Although an increase in dementia cases has often been attributed to an aging population, the researchers also found that the rate of dementia onset within older age groups is also increasing.

Principal investigator Professor Eric Brunner (UCL Institute of Epidemiology & Health Care) said, "Our research has exposed that dementia is likely to be a more urgent policy problem than previously recognized—even if the current trend continues for just a few years. We have found that not only is the aging population a major driver of the trend in England and Wales, but also the number of people developing dementia within older age groups is increasing.

"We don't know how long this pattern will continue, but the UK needs to be prepared so we can ensure that everyone affected, whatever their financial circumstances, is able to access the help and support that they need."

James White, Alzheimer's Society's Head of National Influencing, commented, "Dementia is the biggest health and social care issue of our time. Statistics from this Lancet Public Health study are a stark reminder that without action, the individual and economic devastation caused by dementia shows no sign of stopping.

"We know that one in three people born in the UK today will develop this terminal condition in their lifetime. With prevalence on the rise, improving diagnosis has never been more important. Everyone living with dementia must have access to a timely, accurate and specific diagnosis, and who you are or where you live should have no bearing on this. The figures also make it clear that pressure on our already struggling social care system is only going to increase.

"Quality social care can make a huge difference to people's lives, but we know that people with dementia—who are the biggest users of social care—are struggling with a care system that's costly, difficult to access, and too often not tailored to their needs."