Gutiérrez-Zúñiga Raquel, Davis James R C, Ruddy Kathy, De Looze Céline, Carey Daniel, Meaney James, Kenny Rose Anne, Knight Silvin Paul, Romero-Ortuno Roman
Global Brain Health Institute, Trinity College Dublin, Dublin, Ireland.
The Irish Longitudinal Study on Ageing, Trinity College Dublin, Dublin, Ireland.
Front Aging Neurosci. 2023 Jan 19;15:1065191. doi: 10.3389/fnagi.2023.1065191. eCollection 2023.
Frailty in older adults has been associated with reduced brain health. However, structural brain signatures of frailty remain understudied. Our aims were: (1) Explore associations between a frailty index (FI) and brain structure on magnetic resonance imaging (MRI). (2) Identify the most important FI features driving the associations.
We designed a cross-sectional observational study from a population-based study (The Irish Longitudinal Study on Aging: TILDA). Participants aged ≥50 years who underwent the wave 3 MRI sub-study were included. We measured cortex, basal ganglia, and each of the Desikan-Killiany regional volumes. Age-and sex-adjusted correlations were performed with a 32-item self-reported FI that included conditions commonly tested for frailty in research and clinical settings. A graph theory analysis of the network composed by each FI item and cortex volume was performed. White matter fiber integrity was quantified using diffusion tensor imaging (DTI).
In 523 participants (mean age 69, 49% men), lower cortex and thalamic volumes were independently associated with higher FI. Sensory and functional difficulties, diabetes, polypharmacy, knee pain, and self-reported health were the main FI associations with cortex volume. In the network analysis, cortex volume had a modest influence within the frailty network. Regionally, higher FI was significantly associated with lower volumes in both orbitofrontal and temporal cortices. DTI analyses revealed inverse associations between the FI and the integrity of some association bundles.
The FI used had a recognizable but subtle structural brain signature in this sample. Only some FI deficits were directly associated with cortex volume, suggesting scope for developing FIs that include metrics more specifically related with brain health in future aging neuroscience studies.
老年人的虚弱与大脑健康下降有关。然而，虚弱的大脑结构特征仍未得到充分研究。我们的目标是：（1）探讨虚弱指数（FI）与磁共振成像（MRI）上的脑结构之间的关联。（2）确定驱动这些关联的最重要的FI特征。
我们从一项基于人群的研究（爱尔兰老龄化纵向研究：TILDA）中设计了一项横断面观察性研究。纳入年龄≥50岁且接受了第3波MRI子研究的参与者。我们测量了皮质、基底神经节以及每个Desikan-Killiany区域的体积。使用一份包含32项自我报告的FI进行年龄和性别调整后的相关性分析，该FI包括研究和临床环境中常用于检测虚弱的状况。对由每个FI项目和皮质体积组成的网络进行了图论分析。使用扩散张量成像（DTI）对白质纤维完整性进行量化。
在523名参与者（平均年龄69岁，49%为男性）中，较低的皮质和丘脑体积与较高的FI独立相关。感觉和功能困难、糖尿病、多种药物治疗、膝关节疼痛和自我报告的健康状况是FI与皮质体积的主要关联因素。在网络分析中，皮质体积在虚弱网络中影响较小。在区域上，较高的FI与眶额皮质和颞叶皮质的较低体积显著相关。DTI分析显示FI与一些联合束的完整性之间存在负相关。
在本样本中，所使用的FI具有可识别但微妙的脑结构特征。只有一些FI缺陷与皮质体积直接相关，这表明在未来的衰老神经科学研究中，开发包含与大脑健康更具体相关指标的FI具有空间。
