What decades of research has taught us about brain health and dementia risk

Did you spot Alzheimer’s Research UK on BBC One’s The One Show this evening? Here’s what the segment was all about. 

Back in 1946, more than 5,000 babies were enrolled in an ambitious new population study: the National Survey of Health and Development (NSHD). 

Eight decades later, many of those babies – now in their 80s – are still taking part in health checks and examinations. By generously giving their time, they’ve helped create the world’s longest continuously studied birth cohort, providing an extraordinary insight into how our health changes throughout life. 

For the past decade, this research has included Insight 46, a major sub-study funded by Alzheimer’s Research UK and other research organisations. Through repeated brain scans and cognitive tests, participants have helped researchers understand more about how our brains change with age and what this could mean for dementia risk. 

Earlier this month, more than 200 participants from the cohort came together at Senate House in London to celebrate their 80th birthdays. There were science-led talks and plenty of cake, including one cut by Alzheimer’s Research UK supporter and actress Anita Harris who lost her husband, Mike Margolis, to Alzheimer’s disease in 2023.

This special milestone, organised by University College London (UCL), is what featured on The One Show this evening. The segment highlighted exactly what Insight 46 and the wider NSHD has discovered. 

Want to know more about what Insight 46 is? We’ve answered some key questions about the study below. 

What is Insight 46? 

Insight 46 is a research study that launched in 2015, drawing on data from the 1946 birth cohort to explore how our everyday choices shape brain health throughout our lives. 

This unique dataset has revealed how often-overlooked factors, such as blood pressure and exercise, can influence our long-term brain health. 

What has Insight 46 taught us about the brain? 

Insight 46 has completely reshaped how scientists think about dementia. It has revealed that many Alzheimer’s‑related brain changes start decades before symptoms appear.    

Its findings are shifting the conversation from treating dementia to recognising, identifying, and potentially reducing risk much earlier in life.   

Evidence from Insight 46, along with wider dementia risk research, has directly shaped Alzheimer’s Research UK’s Think Brain Health campaign, which highlights the key risk factors we may be able to change.    

Understanding more about the factors that influence brain health offers real hope for people living with dementia today. By addressing risk early, it is possible to lay the groundwork for more effective ways to protect brain health over the long term.   

Key findings from Insight 46

• Having high blood pressure in midlife may affect brain health later on. By around age 70, high blood pressure may be linked to a slightly smaller brain and more damage to blood vessels in the brain. This can increase dementia risk.  

• Having a head injury that causes loss of consciousness in your 50s or earlier may affect brain health later in life. By around age 70, people who had experienced this type of injury scored lower than expected on memory and thinking tests and had subtle changes in brain structure. These changes are not direct markers of dementia but may suggest a greater risk of developing it in the future.  

• Exercising regularly before the age of 50 is linked to a larger hippocampus at 70. This is the part of the brain responsible for memory and often the first region of the brain affected in Alzheimer’s disease. 

Being part of Insight 46 

To thank the study participants, UCL hosted a day-long celebration featuring talks on the study’s findings, followed by a party and a big cake. 

Among those in attendance was Sheila, an Insight 46 participant from London. Having seen the impact of dementia on her friends, she hopes research like this will help future generations.

“Taking part in Insight46 was fantastic,” she said. “I had a number of brain scans. Some people hate them, but I rather like them.  

“It was like having a sound installation inside my head. I found it fascinating and felt very privileged to have access to all the medical equipment and specialists. 

 

“What I hope for the study is that it helps scientists learn more about healthy ageing and detecting brain changes that might tell us more about who is at a greater risk of developing dementia and Alzheimer’s. 

“I think spotting the early signs is a good start. Then we can learn more about how to treat and prevent it.” 

Retired property developer Donald, from Scotland, has also taken part in Insight 46 and spoke to us about the study’s ‘extraordinary’ impact over time.  

Donald, aged 80, said: “The whole experience has been positive. I feel increasingly proud to have taken part in it. I would say we’re very fortunate to have had this opportunity in life.   

“It’s a nice feeling to know you’ve made a difference. I hope the study has a good impact on what we know about brain ageing and dementia. Being part of it feels like you’re laying down a track which is going to be followed for years to come. A real legacy for dementia research.”    

Take part in research  

If you want to take part in life-changing research projects, you can. Anyone of any age can sign up to Join Dementia Research, which matches volunteers to relevant studies in their area.  

For more information, visit:   

Join dementia research – register your interest in dementia research : Home  

*Insight46 was established and funded by Alzheimer’s Research UK, The Wolfson Foundation and the Medical Research Council Dementias Platform UK, has monitored participants through detailed brain scans and cognitive tests for over a decade.