Which vascular risk factors are associated with the risk of developing dementia may vary with age. A new study shows that among people around age 55, the risk of developing dementia over the next 10 years was increased in those with diabetes and high blood pressure. For people around 65 years old, the risk was higher in those with heart disease, and for those in their 70s, diabetes and stroke. For 80-year-olds, the risk of developing dementia was increased in those with diabetes and a history of stroke, while taking blood pressure medications decreased the risk. The study is published in the May 18, 2022, online issue of Neurology^®, the medical journal of the American Academy of Neurology.

These findings can help us to more accurately predict a person's future risk of developing dementia and make individualized recommendations on lifestyle changes and risk factor control to help reduce their risk of dementia later on."

Emer R. McGrath, MB, PhD, study author, National University of Ireland Galway and member of the American Academy of Neurology

For the study, researchers looked at data from the Framingham Heart Study, including 4,899 people at about age 55 years, 2,386 of whom remained dementia free and had data available at around age 80. Starting at age 65, the participants were followed to see who developed dementia.

People who had diabetes when they were 55 years old were over four times more likely to later develop dementia than people who did not have diabetes at that age. And 55-year-olds with high blood pressure were more likely to develop dementia, with the risk increasing by about 12% for every 10-point increase in systolic blood pressure, which is the top number in the reading.

People who had cardiovascular disease when they were 65 years old were nearly twice as likely to later develop dementia as those who did not have those conditions. This could include a heart attack or other heart conditions, but not stroke.

People in their 70s who had diabetes and stroke were more likely to develop dementia. For 80-year-olds, people who had a stroke or diabetes were about 40% to 60% more likely to develop dementia.

"Dementia is a complicated disease and risk prediction scores need to be tailored to the individual," McGrath said. "Our findings support the use of age-specific risk prediction scores for dementia instead of a one-size-fits-all approach."

A limitation of the study is that most participants were white people, so the results may not apply to people of other ethnicities.

The study was supported by the Health Research Board of Ireland, Alzheimer's Association, National Heart, Lung, and Blood Institute, National Institute on Aging and the National Institute of Neurological Disorders and Stroke.