心血管病危险因素在正常老人认知功能动态轨迹中的作用及机制探讨

正常老人的认知功能动态变化差异较大，申请人前期发现近5%正常老人的认知功能在12年随访期间出现快速下降，心血管疾病可能加剧这一趋势，而心血管病危险因素对认知功能动态轨迹的影响尚无定论。此外，心血管危险因素与认知功能之间的潜在机制尚不明确。为此，本项目拟开展两部分研究：其一，拟基于中国老年健康影响因素跟踪调查（CLHLS）随访队列，利用组基轨迹模型拟合正常老人的认知功能动态轨迹，通过参数G-formula模型评估心血管病危险因素在认知功能动态轨迹中的作用。其二，拟依据心血管病危险因素不同等级（多、中、少）纳入认知正常老人各30名，考察心血管病危险因素对脑血流特征及脑功能连接的影响，利用结构方程模型探索脑血流特征及脑功能连接在心血管病危险因素与认知功能关联之间的作用路径。本项目有望为从血管功能健康视角减缓认知功能衰退提供新思路，为阐明心血管危险因素影响认知功能的潜在神经血管机制提供重要参考。

The cognitive trajectory varies among non-demented older adults. In a 12-year follow-up study, we found approximately 5% participants presented rapid cognitive decline. Cardiovascular diseases increased the risk of cognitive decline. However, the influence of cardiovascular risk factors on cognitive decline remained inconsistent. Besides, the potential neurovascular mechanism of the cardiovascular risk factors and cognitive function has not been fully investigated. Therefore, the proposed program will include two sub-studies. The first sub-study will use the longitudinal data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Group-based trajectory modeling will be used to identify potential trajectories of cognitive function among cognitively intact older adults. The parametric G-formula modeling will be used to evaluate the influence of cardiovascular risk factors on the trajectories of cognitive function. The second sub-study will recruit 30 dementia-free older adults in each group of different levels of cardiovascular risk factors, i.e., high, medium and low risk. The influence of cardiovascular risk factors on the characteristics of cerebral blood flow and brain functional connectivity will be assessed. Further, the association among cardiovascular risk factors, cerebral blood flow, brain functional connectivity and cognitive function will be investigated with structural equation modeling. It is anticipated that the findings of the proposed program will provide novel insight on preventing cognitive decline from the angle of maintaining health vascular function, and will provide evidence in elucidating the potential neurovascular mechanism between cardiovascular risk factors and cognitive function.