Supplementary Material for: Blood-Based Oxidative Stress Markers and Cognitive Performance in Early Old Age: The HAPIEE Study

<b><i>Background/Aims:</i></b> Oxidative stress is involved in Alzheimer disease pathology, but its impact on cognitive function in community-dwelling older adults remains unknown. We estimated associations between serum oxidative stress markers and cognitive function in early old age. <b><i>Methods:</i></b> Subjects aged 45-69 years recruited in urban centers in Central and Eastern Europe had memory, verbal fluency, and processing speed assessed at baseline (2002-2005) and 3 years later. Derivatives of reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), and total thiol levels (TTLs) were measured at baseline in a subsample. Linear regression was used to estimate associations of biomarkers with cognitive test scores cross-sectionally (<i>n</i> = 4,304) and prospectively (<i>n</i> = 2,882). <b><i>Results:</i></b> Increased d-ROM levels were inversely associated with global cognition and verbal fluency cross-sectionally and in prospective analysis; observed effects corresponded to 3-4 years' higher age. TTL was inconsistently associated with memory. BAP was not related to cognitive function. <b><i>Conclusion:</i></b> This study found modest evidence for a relationship between serum d-ROMs and cognitive function in a population sample of older adults.

**背景与目的**：氧化应激（oxidative stress）参与阿尔茨海默病（Alzheimer disease）的病理进程，但目前尚不清楚其对社区居住老年群体认知功能的影响。本研究旨在评估早老阶段人群血清氧化应激标志物与认知功能的相关性。**研究方法**：本研究的研究对象为中东欧城市中心招募的45-69岁人群，分别于基线（2002-2005年）及随访3年后对其记忆功能、言语流畅性与信息处理速度进行评估。本研究亚组在基线时检测了反应氧代谢产物衍生物（d-ROMs）、生物抗氧化潜能（BAP）以及总巯基水平（TTLs）。本研究采用线性回归模型，分别在横断面分析（n=4304）与前瞻性分析（n=2882）中评估生物标志物与认知测验得分的相关性。**研究结果**：横断面与前瞻性分析均显示，血清d-ROMs水平升高与整体认知功能及言语流畅性呈负相关，其观测到的效应相当于年龄增长3-4年所带来的认知变化。总巯基水平（TTLs）与记忆功能的相关性并不稳定。生物抗氧化潜能（BAP）与认知功能无显著关联。**研究结论**：本研究在老年人群体样本中，发现血清d-ROMs水平与认知功能存在关联，相关证据较为有限。