The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 13 No.
3 • June 2010
Predicting Future Cognitive Decline
Markers Help Predict Future Cognitive Decline
In Individuals Without Dementia
In a new paper, researchers investigated possible markers for helping anticipate future cognitive decline in people who currently have no signs of dementia. They used data from 2312 male and female subjects aged 50–80 participating in the Aspirin for Asymptomatic Atherosclerosis Trial, a large prospective study based in central Scotland. The results showed that increased levels of plasma fibrinogen (which increases with aging and is associated with greater “stickiness” of blood) and C-reactive protein (CRP, a marker for inflammation) were associated with poorer general cognitive ability, nonverbal reasoning, executive function (CRP only), processing speed, and mental flexibility after 5 years of follow-up and after adjustment for age and sex. They also found significant associations between CRP and fibrinogen and 5-year decline in executive function and nonverbal reasoning, respectively. The researchers reported that baseline plasma viscosity was associated with late-life general cognitive ability, processing speed, and mental flexibility, and with estimated lifetime cognitive decline and 5-year decline in mental flexibility. Since plasma fibrinogen is a major determinant of blood viscosity, the fact that the effects of increasing blood viscosity followed in the same direction as increasing fibrinogen is not surprising. However, adjusting for fibrinogen levels did not account for all of the changes due to increasing blood viscosity, so (as the authors suggest) other factors active in regulation of blood viscosity may be involved.
The researchers note that the effect sizes for the association between inflammatory markers (CRP) and cognitive ability were small, but the results were consistent with other studies. Though causality is still difficult to assess (for example, it may be that poorer cognitive ability in earlier life may be linked to conditions that increase inflammation in later life), it still may be useful to include tests for CRP, fibrinogen, and blood viscosity in your regular tests for assessing your state of cognitive decline in aging.
- Marioni et al. Peripheral levels of fibrinogen, C-reactive protein, and plasma viscosity predict future cognitive decline in individuals without dementia. Psychosom Med 71(8):901-6 (2009).