Background: Inflammatory processes may be involved in the development of dementia, although findings from epidemiologic studies directly examining inflammatory markers and dementia or its precursor, impaired cognitive function, are inconsistent.
Methods: We measured plasma levels of the inflammatory marker, C-reactive protein, using a high-sensitivity assay (hs-CRP) in 4,231 older participants of the Women's Health Study, who provided blood samples between 1992 and 1996 when they were age 60 to 90 years. From 1998 to 2000, we administered a battery of 5 cognitive tests measuring general cognition, verbal memory, and category fluency. Using multiple linear regression, we compared mean cognitive test scores across quintiles of hs-CRP, adjusting for potential confounding factors.
Results: There was a wide distribution of hs-CRP levels among these women, and a large proportion had levels considered to reflect a high risk of cardiovascular disease. We observed no suggestion, however, that higher hs-CRP levels were associated with poorer cognitive performance. For example, on a global score combining results of all the cognitive tests, mean scores among women in the highest quintile of hs-CRP did not differ from those in the lowest quintile (multivariable-adjusted mean difference = 0.04; 95% confidence interval [CI]: -0.02 to 0.11, P for trend across quintiles = 0.38).
Conclusion: Overall, in these women, we found no evidence of a link between hs-CRP, a marker of inflammation, and decrements in cognitive function.