Aging is the collective physiological, functional, and mental changes that accrue in a biological organism over time. However, people age at different rates, a consequence of both genetic and environmental factors. A recent study found that people whose biological age is five years older than their chronological age are roughly 40 percent more likely to develop vascular dementia or experience a stroke than those whose biological and chronological ages align.

Using 18 routinely measured clinical biomarkers, researchers calculated the biological ages of more than 325,000 people enrolled in the UK Biobank study. Then, they evaluated how older biological age influenced the occurrence of neurological conditions, including dementia of all types, stroke, Parkinson’s disease, and motor neuron disease, over a nine-year follow-up period.

They found that nearly 1,400 participants developed dementia, and more than 2,500 experienced a stroke. Having an older biological age that was five years older than chronological age increased the participants' risk of dementia by 26 percent, vascular dementia by 41 percent, and stroke by 39 percent. The findings were consistent even after considering various disease-specific risk factors.

These findings suggest that accelerated biological aging markedly increases the risk of dementia and stroke. Age acceleration can result from intrinsic factors, such as normal metabolism and genetics, or extrinsic factors, such as diet, smoking, and exercise. Learn how epigenetic changes influence biological aging in our overview article.

• Read study abstract.