High-sensitivity C-reactive protein (hs-CRP) is the most widely studied biomarker of systemic inflammation. Its level has been reported to be associated with cognitive impairment. While dementia and cognitive impairment are common non-motor symptoms in advanced idiopathic Parkinson's disease (PD), the clinical value of hs-CRP for predicting dementia in PD patients remains unclear. Therefore, the objective of this study was to clarify the relationship between hs-CRP levels and the development or progression of dementia in PD through evaluating hs-CRP levels in PD patients with or without dementia.

A total of 112 PD patients without dementia (PD-D), 103 PD patients with dementia (PD+D), and 94 healthy controls were used in this study. The levels of hs-CRP and cognitive function were analyzed among these three groups.

The mean serum hs-CRP levels in PD-D and PD+D were 1.76±3.62 mg/dL and 1.44±2.78 mg/dL, respectively, which were significantly ( p =0.02) higher than that (vs. 0.41±1.06 mg/dL) in healthy controls. However, the levels of hs-CRP were not significantly ( p >0.05) different between PD-D and PD+D.

Our results suggest that neuro-inflammation plays a role in the pathogenesis of PD. However, it does not significantly contribute to the development or the progression of dementia in PD patients.