Cognitive decline and markers of inflammation and hemostasis: The Edinburgh Artery Study

OBJECTIVES: To determine whether circulating markers of activated inflammation and hemostasisare associated with cognitive decline in older people. DESIGN: Prospective cohort study (Edinburgh Artery Study). SETTING: Eleven general practices in Edinburgh, Scotland. PARTICIPANTS: A sample of 452 men and women followed for 16 years. MEASUREMENTS: Biomarker data were collected in 1987/88, and cognitive assessment was first conducted in 1998/99, when the mean age of the sample ± standard deviation was 73.1±5.0), and subsequently in 2002/03. Information was obtained on verbal declarative memory(Wechsler Logical Memory Test (LMT)), nonverbal reasoning (Raven's Standard Progressive Matrices), verbal fluency ( Verbal Fluency Test), information processing speed (Wechsler Digit Symbol Test), and a general cognitive factor representing the variance common to the individual test scores. RESULTS: In age-adjusted analyses, plasma fibrinogen, interleukin-6 (IL-6), and intercellular adhesion molecule1 (ICAM-1) were negatively associated with performance on all cognitive measures in 2002/03 except the LMT (correlation coefficients from −0.10 to −0.24). In multivariate analyses controlling for demographic characteristics, depression, and cardiovascular morbidity and risk factors, fibrinogen independently predicted 4-year decline in nonverbal reasoning (P<.05). Also, when cognitive change was estimated from peak prior level, IL-6 turned out to be inversely related to decline in information processing speed (P<.05). Similarly, ICAM-1 was associated with a greater decline in general cognitive ability (P<.05) and nonverbal ability (P<.05). CONCLUSION: Systemic markers of inflammation and hemostasisare associated with a progressive decline in general and specific cognitive abilities in older people, independent of major vascular comorbidity.