HOUSTON — People who have heart disease risks in middle age are more likely to have dementia later in life, according to a study presented Wednesday at the American Stroke Association’s International Stroke Conference 2017.

“The health of your vascular system in midlife is really important to the health of your brain when you are older,” said Rebecca F. Gottesman, M.D., Ph.D., associate professor of neurology and epidemiology at the Johns Hopkins University in Baltimore, Maryland.

In the ongoing study that began in 1987 and enrolled 15,744 people in four U.S. communities, the risk of dementia increased as people got older. Heart disease risks such as diabetes, high blood pressure or smoking detected at the start of the study, when participants were 45-64 years old, also had a significant impact on later dementia.

During the study, dementia developed in 1,516 people and the risk of the condition later in life was 41 percent higher in midlife smokers than in non-smokers or former smokers; 39 percent higher in people with high blood pressure (greater than 140/90 mmHg) in middle age and 31 percent higher in those with pre-hypertension (between 120/80 mmHg and 139/89 mmHg) compared to those with normal blood pressure; and 77 percent higher in people with diabetes in middle age than in non-diabetics.

“Diabetes raises the risk almost as much as the most important known genetic risk factor for Alzheimer’s disease,” Gottesman said.

Furthermore, the risk of dementia was 11 percent lower in women and highest in blacks, those who had less than a high school education, older, carried the gene that increases Alzheimer’s risk, or had high blood pressure, diabetes or smoked at the time of initial evaluation.

Smoking and carrying the gene that increases the chance of Alzheimer’s were stronger risk factors in whites than in blacks, Gottesman said.

“If you knew you carried the gene increasing Alzheimer’s risk, you would know you were predisposed to dementia, but people don’t necessarily think of heart disease risks in the same way,” she said. “If you want to protect your brain as you get older, stop smoking, watch your weight and go to the doctor so diabetes and high blood pressure can be detected and treated.”