According to a new study, Alzheimer's patients with a history of diabetes and elevated levels of cholesterol, especially LDL cholesterol, are more prone to faster cognitive decline.
The results of the study by Columbia University Medical Center researchers, has provided further evidence of the role of vascular risk factors in the onset and progression of Alzheimer's disease.
"These findings indicate that controlling vascular conditions may be one way to delay the course of Alzheimer's, which would be a major development in the treatment of this devastating disease as currently there are few treatments available to slow its progression," said Yaakov Stern, Ph.D., a professor at the Taub Institute for the Research on Alzheimer's Disease and the Aging.
He added: "Preventing heart disease, stroke and diabetes, or making sure these conditions are well managed in patients diagnosed with them, can potentially slow the disease progression of Alzheimer's."
From the study, the researchers used longitudinal data for a mean of 3.5 years (up to 10.2 years) for 156 people diagnosed with Alzheimer's disease who were participants in the Washington Heights/Inwood Columbia Aging Project, a 10-year multi-ethnic, prospective, epidemiological study of cognitive aging and dementia in northern Manhattan.
"Through the Washington Heights/Inwood Columbia Aging Project, we were able to follow patients before they began to show symptoms of Alzheimer's and for several years following their diagnosis. This makes our estimates of progression much more powerful, since we were able to know exactly when cognitive decline began," said Stern.
It was found that a history of diabetes and higher cholesterol levels (total cholesterol and LDL-C) was associated with faster cognitive decline.
A history of heart disease and stroke was found to be associated with cognitive decline only in carriers of the apolipoprotein E e4 (APOE-e4) gene, which has been implicated in late-onset Alzheimer's disease.
The authors wrote: "There has been intense interest in identifying modifiable Alzheimer's disease risk factors such as cardiovascular risk factors, with the goal of preventing or at least delaying disease onset. However, little attention has been given to the influence of these factors on disease progression."
The researchers said that the link between vascular risk factors and faster cognitive decline in patients with Alzheimer's disease may occur because vascular diseases may increase oxidative stress or activate inflammation in the brain.
This could trigger the production of amyloid, and/or triggering the formation of neuron tangles, known as neurofibrillary tangles, which are believed to be a primary cause of Alzheimer's disease.
Now researchers are trying to study the basis of the links between vascular risk factors and alzheimer's disease using epidemiologic and imaging approaches.
The study will be published in the March 2009 issue of Archives of Neurology.