Having type 2 diabetes in middle age could mean being four times more likely to develop dementia.
Diabetes is linked to dementia, with experts suspecting it can lead to the build-up of potentially harmful proteins in the brain.
Researchers looked at almost 5,000 people who were tracked over a decade to see if they developed dementia.
They found people aged 55 who had diabetes had four times the risk of getting dementia in the decade after they turned 65.
Most will have had type 2 diabetes, which is linked to an unhealthy diet and being overweight.
Diabetes and high blood pressure were the biggest risks for dementia in people aged 55.
For those aged 65, having cardiovascular disease, like a previous heart attack or angina, was the biggest risk linked to dementia.
People aged 70 and older had the greatest risk of dementia if they had previously had a stroke or had diabetes.
Having type 2 diabetes in middle age could mean being four times more likely to develop dementia
Professor Emer McGrath, who led the study from the National University of Ireland Galway, said: ‘This shows that people who have diabetes in their fifties are more likely to develop dementia – probably because having the condition at a younger age can do more damage to your body and brain.
‘It matters because these people have four times the risk of dementia in the decade after most people enter retirement.
‘No one wants to be diagnosed with a condition like Alzheimer’s disease when they are retired, have stopped working, and want to start enjoying their life without worries.’
More than 325,000 people are living with dementia in England – but have not been diagnosed
More than 325,000 people in England are living with dementia but have not been diagnosed, according to a study.
Diagnosis rates have fallen below the Government’s target of two-thirds since the pandemic began.
The report found there is a postcode lottery in terms of who is diagnosed, with proportions ranging from 83 per cent to less than 50 per cent.
NHS England set an ambition in 2013 for two-thirds of people with dementia in England to have a diagnosis and follow-up support.
But the rate fell from 68 per cent in February 2020 to 62 per cent in March, NHS Digital said.
Consultancy Future Health said the data suggests more than 325,000 people in England may have undiagnosed dementia.
The report said that from 2020 to 2021, 430,000 people had a formal diagnosis but around four in ten of those with dementia did not.
It found the Midlands has the highest proportion of undiagnosed dementia, while London and the North West have the lowest.
But the analysis also uncovered regional variations. In Stoke-on-Trent, the rate of diagnosis is 83 per cent, compared with 48 per cent in nearby Stafford.
Around 676,000 people in England and 850,000 across the UK are estimated to have dementia.
The NHS Digital figures compare the number of people thought to have dementia with the number of people diagnosed with it.
The study, published in the journal Neurology, shows how the factors which may lead to dementia change at different ages.
Researchers looked at middle-aged people aged 55, those in later life aged 65 and 70, and older people aged 75 and 80.
For each group, they looked at whether people had had a stroke, if they had heart disease, diabetes or an irregular heartbeat, and if they took blood pressure pills.
People with diabetes at the age of 55 were 4.3 times more likely to get dementia in the decade after they turned 65.
But those who had diabetes at the age of 65 were only twice as likely to get dementia in the next decade.
This suggests it is worse for the brain to have the condition from a younger age.
For people aged 65, the risk of getting dementia was most strongly linked to whether someone had cardiovascular disease, such as a heart attack or angina, which may also affect the brain.
At aged 55, diabetes and systolic blood pressure were most important, with every ten-point increase in someone’s top blood pressure number — which shows the force at which the heart pumps blood around the body — linked to a 12 per cent higher risk of dementia.
Diabetes and a history of stroke, which more than tripled the risk of dementia in people aged 70, was most important for those aged 70 and 75.
At the age of 80, the biggest factors linked to dementia risk were diabetes, linked to being 40 per cent more likely to develop dementia, as well as having had a stroke and whether they were taking blood pressure pills.
These pills may aid the brain by keeping blood pressure and flow under control, but only for some people.
The study, published in the journal Neurology, looked at people from the US and took their age and sex into account when working out their dementia risk.
Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: ‘The findings from this study confirm existing research, which links vascular risk factors, such as high blood pressure and diabetes, with an increased risk of developing dementia in later life.
‘We know that poorer vascular health can increase the chances of developing small vessel disease and other conditions that affect blood flow in the brain, which then damages our brain cells irreparably.
‘Studies like this are good for highlighting links, but we need to understand more about why and how these conditions affect dementia risk.
‘With this knowledge, researchers can then design treatments and prevention strategies to benefit people in their midlife – a critical timepoint for reducing your risk of dementia.’