C-reactive protein plays a marginal role in cognitive decline: a systematic review and meta-analysis.

OBJECTIVE

The objective of the study was to investigate the association between peripheral levels of C-reactive protein (CRP) and cognitive decline that is defined by 2-5 years of cognitive change in general cognitive function or specific cognitive domain.

METHODS

We searched PubMed and Google for prospective/longitudinal studies that report the association between peripheral levels of CRP and risk of cognitive decline in the nondementia population.

RESULTS

Out of 479 related articles from PubMed and Google, four studies with a total of 5255 non-demented subjects that report odds ratio (OR)/relative risk/hazard ratio of CRP levels and decline in general cognition met our criteria for meta-analysis. The association between higher levels of CRP and risk of global cognitive decline was weak but significant (OR, 1.27 [95% CI, 1.02 to 1.58]). However, the systematic review from six other articles that were not suitable for meta-analysis revealed a marginal association between CRP and cognitive decline in certain domains.

CONCLUSION

Our analysis demonstrated a weak association between peripheral CRP level and global cognitive decline. Because of the small number of included studies and varied methodologies that they applied, caution should be taken when generalizing our finding to the full range of cognitive changes in different cognitive domains observed in non-demented people.