Fibrinogen and risk of dementia: A systematic review and meta-analysis

The aim of this meta-analysis is to evaluate the association of fibrinogen with risk of dementia and its subtypes.

Embase, Pubmed and Web of Science were retrieved systematically up to February 2019. Standard mean difference (SMD) with 95 % confidence intervals was estimated using random-effects models.

Sixteen studies involving 3,649 participants were summarized. Patients with all-cause dementia exhibited higher fibrinogen levels than those in non-dementia controls (SMD = 0.90 [0.43;1.36] p < 0.01). Further subgroup analysis revealed a positive association of fibrinogen with vascular dementia (VaD) (SMD = 1.11 [0.45;1.78] p < 0.01) rather than Alzheimer's disease (AD) (SMD = 0.01 [-0.17;0.19]) p = 0.92) and Parkinson's disease dementia (PDD) (SMD = 0.35 [-0.23;0.93] p = 0.24). This correlation was significant in Europeans (SMD = 0.92 [0.34;1.49] p < 0.01), but probably not in Asian based populations (SMD = 1.04 [-0.09;2.17] p = 0.07), and gradually declined with advancing age (60 ≤ age < 70: SMD = 1.22 [0.38;2.06] p < 0.01; 70 ≤ age < 80: SMD = 0.29 [0.04;0.53] p = 0.02; age ≥ 80: SMD = 0.01 [-0.12;0.15] p = 0.84).

Plasma fibrinogen is a potential risk factor for all-cause dementia and VaD under the age of 80, and is more obvious in cohorts with people of European descent.