By Steven Reinberg
Risk factors such as smoking, high blood pressure and diabetes might boost the odds of dementia almost as much as carrying the gene that raises the risk of Alzheimer's disease, the researchers reported.
"Most of these risk factors are treatable or preventable. And it is important to treat these vascular [circulatory system] risk factors starting at least in middle age, if not earlier," said lead researcher Dr. Rebecca Gottesman. She's an associate professor of neurology and epidemiology at Johns Hopkins University in Baltimore.
Gottesman said there's no guarantee that controlling these heart risk factors will reduce the risk of dementia, but it's likely they will.
For the study, Gottesman and her colleagues collected data on more than 15,700 men and women who took part in a study that started in 1987 in four communities around the United States.
Over the course of the study, the risk for dementia increased as expected, Gottesman said. But those people who had a risk for heart disease at the beginning of the study, when they were between the ages of 45 and 64, had a significantly higher risk for dementia, she added.
During the study period, more than 1,500 people developed dementia. The risk was 41 percent higher among middle-aged smokers, 39 percent higher among those with high blood pressure (140/90 mm Hg or higher), and 31 percent higher for those with borderline high blood pressure (between 120/80 mm Hg and 139/89 mm Hg), the researchers found.
Diabetes in middle age, however, was linked with the highest risk for dementia -- 77 percent, compared with people without diabetes, Gottesman said.
The findings were to be presented Wednesday at the International Stroke Conference in Houston.
Dr. Sam Gandy, director of the Center for Cognitive Health at Mount Sinai Hospital in New York City, said it makes sense that diseases that affect blood circulation will affect the brain.
"These findings fit well with the notion that Alzheimer's is related to midlife risks that set you up for late-life brain degeneration," Gandy said.
Research presented at meetings is considered preliminary until published in a peer-reviewed journal.