By Michael Smith, North American Correspondent, MedPage Today
Published: April 01, 2013
Reviewed by F. Perry Wilson, MD, MSCE; Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner
· Note that this analysis of a large cohort study demonstrated that cognitive decline could be predicted better by Framingham cardiovascular risk scores than a specific dementia risk score.
· Be aware that the dementia risk score performed better in terms of predicting decline in memory -- suggesting it may be an appropriate tool to examine risk of Alzheimer's dementia.
Standard risk prediction tools for heart disease and stroke are better at predicting declining mental powers than a specific dementia risk score, researchers reported.
In a long-running cohort study, higher risks on the widely used Framingham cardiovascular disease and stroke scores were strongly associated with declines on four out of five cognitive tests, according to Sara Kaffashian, PhD, of the French National Institute of Health and Medical Research in Paris, and colleagues.
On the other hand, higher risk on the recently proposed Cardiovascular Risk Factors, Aging and Dementia (CAIDE) score was less strongly associated with declines and only on three of the five tests, Kaffashian and colleagues reported in the April 2 issue of Neurology.
All of the risk scores predict cognitive decline starting in late middle age, Kaffashian said in a statement, but the Framingham tests may have an edge in prevention.
"Cardiovascular risk scores may have an advantage over the dementia risk score for use in prevention and for targeting changeable risk factors since they are already used by many physicians," she said.
The varied outcomes, though, might reflect differences in the type of dementia being measured, commented Michael Rafii, MD, PhD, of the University of California San Diego.
"The measures that are being looked at with the stroke measures are more reliable in predicting vascular dementia than Alzheimer's disease, " he told MedPage Today, while the "dementia tool seems to be less correlated with vascular dementia down the road."
The exception is in memory decline, Rafii said, where the Framingham stroke tool performed less well than the CAIDE test. "And that memory decline is really the hallmark of Alzheimer's disease dementia," he said.
The study involved 7,830 participants in the Whitehall II study, who had an average age of 55 when they entered the longitudinal British cohort.
The researchers were able to compare the performance of the CAIDE test with the Framingham cardiovascular tool in 4,374 participants who were free of cardiovascular disease. They compared the CAIDE test with the stroke tool in 5,157 people free of strokes and transient ischemic attacks.
They tested participants in four cognitive domains -- reasoning, memory, verbal fluency (using two tests), and vocabulary -- three times over a 10-year period. As well, they created global cognition scores by combining results from the four domains.
On both the Framingham tools, higher scores at baseline were associated with greater decline on all tests except memory, they found. On the other hand, a higher CAIDE risk was associated with greater decline in reasoning, vocabulary, and global cognition.
Kaffashian and colleagues cautioned that the study is based on a "cohort of office-based employees that may not be entirely representative of the general population."
As well, they noted, participants had a favorable risk profile, so that the reported associations may be underestimates.
On the other hand, the study was well designed and relatively large, so the results are likely to be "meaningful," Rafii commented.
"What would have made this an even stronger study," he said, "would be further gold-standard diagnoses – for example, brain imaging, pathological specimens, or any other validated biomarkers that represent true dementia and its underlying causes."
The study had support from Région Ile-de-France, the Medical Research Council, the British Heart Foundation, the Health and Safety Executive, the French Department of Health, the National Heart, Lung and Blood Institute, the NIH, the National Institute on Aging, the Agency for Health Care Policy Research, and the John D. and Catherine T. MacArthur Foundation.
The authors did not report financial links with industry.
Primary source: Neurology
Kaffashian S, et al "Predicting cognitive decline: A dementia risk score vs the Framingham vascular risk scores" Neurology 2013; 80: 1300–1306.