The risk factors associated with the possibility of developing dementia may vary with age, a new study indicates.
Researchers suggest the findings could help to accurately predict someone’s risk of developing dementia, and enable individualised advice for lifestyle changes.
Among people aged around 55, the risk of developing dementia over the next 10 years was increased in those with diabetes and high blood pressure, the study indicates.
While for people around 65 years old, the risk was higher in those with heart disease, and for those in their 70s, diabetes and stroke.
According to the study, 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.
Study author Emer McGrath, of National University of Ireland, Galway and a member of the American Academy of Neurology, said: “These findings can help us to more accurately predict a person’s future risk of developing dementia and make individualised recommendations on lifestyle changes and risk factor control to help reduce their risk of dementia later on.”
Researchers looked at data from the Framingham Heart Study – an ongoing study in America, including 4,899 people aged around 55 years, 2,386 of whom remained dementia free and had data available at around age 80.
Starting at age 65, they were followed to see who developed dementia.
The study found that people who had diabetes when they were 55 were more than four times more likely to go on to develop dementia than those who did not have diabetes at that age.
While 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 – the top number in the reading.
According to the research, people who had cardiovascular disease when they were 65 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, those who had a stroke or diabetes were around 40% to 60% more likely to develop dementia, the study indicates.
Dr McGrath said: “Dementia is a complicated disease and risk prediction scores need to be tailored to the individual.
“Our findings support the use of age-specific risk prediction scores for dementia instead of a one-size-fits-all approach.”
Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: “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.
“Further work in a more representative group of people will ensure we understand the risk for people from different ethnic backgrounds who we know are already at a greater risk of vascular conditions.
“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.”
The findings are published in the Neurology journal.