Background: Chronic low-grade inflammation, as measured with the peripheral serum marker C-reactive protein (sCRP), may be a risk factor for dementia in elderly persons.
Methods: The relationship between sCRP and score on the Mini-Mental State Examination (MMSE), a commonly used screening cognitive measure, was investigated in 540 well functioning, healthy, and cognitively normal elders (age 73 +/- 6 years). Sociodemographic status, lifestyle, health status, traditional and nontraditional cardiovascular risk factors including plasma total homocysteine (tHcy), and other peripheral blood markers of vascular inflammation (leukocyte count, serum albumin, and plasma fibrinogen) were also assessed.
Results: Risk for having sCRP in the highest decile (>0.7 mg/dl) was significantly higher in individuals with MMSE score 24-25 (odds ratio = 3.07, 95% confidence interval, 1.2-7.9) and 26-28 (odds ratio = 2.10, 95% confidence interval, 1.1-3.9) compared with those scoring above 28 (reference group). Results were unaffected by adjustment for all potential confounders. No association was found between MMSE and peripheral markers of vascular inflammation other than sCRP, but lower MMSE scores were also independently associated with hyperhomocysteinemia (plasma tHcy > 15 mmol/L).
Conclusion: In healthy, cognitively normal elderly community dwellers, increased sCRP levels are associated with concurrent cognitive impairment as measured by MMSE. The association is independent of sociodemographic status, lifestyle, health status, and traditional and nontraditional cardiovascular risk factors including hyperhomocysteinemia. Results support the hypothesis that chronic low-grade inflammation may be involved in age-related cognitive impairment.