The presence in middle age of risk factors for cardiovascular disease, like smoking or High cholesterol, is strongly tied to the development of dementia later in life, investigators in California report.

“What is bad for the heart is also bad for the brain,” Dr. Rachel A. Whitmer said in an interview with AMN Health. “Future research needs to figure out what the mechanisms are.”

Whitmer, with Kaiser Permanente’s Division of Research, Oakland, and her colleagues studied data on 8845 subjects who were members of the HMO and had equal access to medical care.

The team correlated the results of health exams conducted between 1964 and 1973, when the participants were between 40 and 44 years old, and the diagnosis of dementia between 1994 and 2003. Dementia was documented among 721 individuals at ages 66 to 82.

Each of four risk factors - diabetes, high blood pressure, High cholesterol and smoking - was significantly associated with a 20 to 40 percent increased risk of dementia, the authors report in the journal Neurology.

Subjects with all four risk factors had more than double the likelihood of being diagnosed with dementia compared with those with none of the risk factors, after factoring in age, race, gender and education.

“It appears that dementia is not a separate neurodegenerative process that happens in the brain,” Whitmer said. “We’ve shown that there is a vascular side to it.”

She pointed out that all the subjects were members of an HMO, so “certainly they were treated and still they were at a greater risk of dementia versus those who didn’t have these diseases.”

She suggested that earlier, more aggressive treatment of risk factors - improving blood glucose control among people with diabetes, lowering cholesterol levels, reducing high blood pressure, and smoking cessation - may show that “the risk of dementia could be largely modifiable.”

SOURCE: Neurology, January 25, 2005.