NYU Langone Health researchers found that maintaining normal blood pressure, stable blood sugar and avoiding smoking during midlife can delay dementia by 13 years. The U.S. study also revealed that women develop dementia later than men regardless of their risk factors.
More than 900,000 people are currently living with dementia in the UK, a figure expected to rise to over 1.6 million by 2040. Dementia is the leading cause of death, accounting for more than 74,000 deaths a year.
The vast majority of cases occur in people over 65, with risk doubling every five years past that age. Britons over 80 have a one in six chance of developing the condition.
Making healthy lifestyle choices, including regular exercise, eating a balanced diet and managing body weight, has been shown to reduce dementia risk by more than 45 per cent. The latest research indicates that meeting health markers in midlife could stave off the disease by more than a decade.
To measure the effect of different health factors on dementia risk, scientists analysed medical data from more than 12,000 people with an average age of 56. Participants were assessed for high blood pressure, diabetes and smoking, and were followed for an average of 26 years.
During the tracking period, 3,008 participants developed dementia, while 5,238 people died without developing the condition. Individuals with no risk factors developed dementia an average of 13 years later than those with all three factors.
Among participants who had all three risk factors, women still tended to develop dementia later than men. Women lived an average of 18.1 years from the start of tracking without developing dementia, compared to 16.6 years for male study participants.
White participants with all three risk factors also tended to develop dementia later than Black participants by an average of 3.6 years. People can use a symptom checklist to make note of symptoms before talking to a GP, as everyone experiences dementia differently.
"These results suggest that vascular risk reduction may benefit all groups, but that certain populations, such as black adults, may especially benefit from targeted prevention efforts," said Dr Coresh. "Hopefully, these results will encourage people to stop smoking and watch their vascular health closely from age 45 on."
Vascular health and brain damage
High blood pressure is one of the most common risk factors for dementia, yet polls show just over a third of Britons recognise it as such. The condition affects more than 16 million people in the UK and damages delicate brain blood vessels over time, reducing vital blood flow and oxygen.
If left untreated, chronic high blood pressure damage can cause tiny strokes and structural shrinkage in brain areas responsible for memory, as well as white matter injury known as vascular dementia.
Diabetes can be similarly destructive to the brain. Uncontrolled high blood sugar, insulin resistance and damaged blood vessels impair brain cell function, cause chronic inflammation and disrupt the normal clearance of toxic brain proteins associated with cognitive decline.
Smoking damages blood vessels throughout the body, inhibits blood flow and leads to accelerated brain shrinkage in smokers over time. Chemicals in cigarette smoke cause blood to thicken and clot easily, increasing stroke risk, which is a known risk factor for dementia.
Dementia research and NHS guidance
The Daily Mail and Alzheimer's Society have partnered in the Defeating Dementia campaign to beat the disease, which claims 76,000 lives each year as the UK's biggest killer. The campaign aims to raise awareness of the disease in an effort to increase early diagnosis, boost research and improve care.
Dementia patients face what charities describe as a cruel injustice, with many facing high care costs, patchy support and no drugs available on the NHS to slow, cure or prevent the disease. Dementia receives far less research funding than other major illnesses such as cancer, despite costing the UK economy an estimated £42 billion a year.
Charities have warned that progress could stall further after dementia was removed from official NHS planning guidance this year, effectively signalling it should be deprioritised.
"This study adds to growing evidence that looking after our heart health in midlife may help us live more years free from dementia," said Dr Richard Oakley, associate director of research and innovation at Alzheimer's Society. "While no single action can guarantee that you won’t get dementia, evidence shows that what’s good for the heart is often good for the brain."
"Around one in three people born today will develop dementia in their lifetime, yet research suggests that around 45 per cent of dementia cases worldwide could be prevented or delayed by addressing factors that affect our health throughout life," Dr Oakley added.
"Although we’re beginning to understand more about what increases our risk of dementia, there is still a lot to learn," Dr Oakley said. "That’s why Alzheimer’s Society funds world class dementia research, providing hope for the future while transforming lives today. Anyone concerned about their risk of dementia can find out more at alzheimers.org.uk."
