Healthy Midlife Habits Linked to Up to 13 More Years Without Dementia
Keeping blood pressure under control, avoiding diabetes and not smoking during midlife could be associated with substantially more years of life free from dementia, according to new research involving more than 12,000 US adults.
Researchers found that people who had none of three major vascular risk factors at around the age of 55 were estimated to live an average of 30.1 further years without dementia.
By comparison, those who had all three risk factors – hypertension, diabetes and current smoking – were estimated to experience just 17.5 years of dementia-free life from age 55.
The difference amounts to almost 13 years and highlights the potential importance of cardiovascular and vascular health during midlife in supporting healthy brain ageing.
The study, published in Alzheimer’s & Dementia, analysed data from 12,409 participants in the long-running Atherosclerosis Risk in Communities (ARIC) study. Participants had an average age of 56 at the beginning of the analysis, with women accounting for 56% of the cohort.
The ARIC study began in 1986 and was designed to investigate cardiovascular and other health factors that influence health outcomes later in life.
Researchers examined the combined impact of three vascular risk factors – hypertension, diabetes and current smoking – and followed participants for a median of 26.3 years.
During that period, 3,008 cases of dementia were recorded, alongside 5,238 deaths among people who had not received a dementia diagnosis.
The researchers found a clear relationship between the number of midlife vascular risk factors and dementia-free life expectancy. Participants with no identified risk factors had the longest expected period of life without dementia, while those with all three had the shortest.
However, the findings also underline an important distinction. The study found that people with a greater burden of vascular risk factors were more likely to die before developing a recorded dementia diagnosis.
In fact, the estimated lifetime risk of dementia was lower among participants with all three risk factors than among those without any of them. Researchers attributed this apparently counter-intuitive finding to the substantially higher mortality associated with the vascular risk factors.
Among participants who did develop dementia, those without any of the three risk factors lived an estimated 4.1 years with dementia, compared with around three years among those with all three risk factors.
The study also identified differences between population groups. Women generally experienced longer periods of life without dementia than men, while Black participants had fewer dementia-free years than White participants. Participants carrying the APOE ε4 genetic variant, which is associated with increased Alzheimer’s disease risk, also had shorter dementia-free survival than non-carriers.
The researchers suggest that several biological mechanisms could help explain the association between vascular health and cognitive ageing.
High blood pressure and diabetes can contribute to damage affecting blood vessels and the brain, while smoking is associated with oxidative stress and vascular damage. Together, these processes may contribute to stroke risk, damage to small blood vessels in the brain and changes associated with neurodegenerative disease.
The authors said their findings add a different perspective to previous research by considering not simply the probability of developing dementia, but the number of years people can expect to live without the condition.
They emphasised that improving vascular health in midlife could therefore be an important component of strategies aimed at delaying dementia and supporting healthier ageing.
