Cross-sectional studies indicate that normal aging is accompanied by decreases in brain structure. Especially during older ages, however, high inter-individual variability might obscure the intra-individual trajectories of the aging process. Further, methodological differences in study designs, e.g. brain metrics assessed, hamper the generalizability of study results. Therefore, the current study aimed to compare longitudinal age-related changes in brain structure (measured through cortical thickness) in two large independent samples of healthy older adults (n = 161 each); the Longitudinal Healthy Aging Brain (LHAB) database project at the University of Zurich; Switzerland and 1000BRAINS at the Research Center Juelich, Germany. Annual percentage changes in the two samples revealed stable to slight decreases in cortical thickness over time. After correction for major covariates, i.e. baseline age, sex, education, and image quality, sample differences were only marginally present. Results suggest that general trends across time might be generalizable over independent samples, assuming the same methodology is used and similar sample characteristics are present.

中文翻译：

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纵向年龄对大脑结构的影响-两种研究的比较方法

横断面研究表明，正常的衰老伴随着大脑结构的减少。但是，尤其是在老年人中，较高的个体间差异可能会掩盖衰老过程的个体内轨迹。此外，研究设计的方法学差异（例如评估的大脑指标）阻碍了研究结果的普遍性。因此，当前的研究旨在比较两个较大的健康老年人独立样本（每个n = 161）中与年龄相关的纵向纵向脑结构变化（通过皮层厚度测量）；苏黎世大学的纵向健康老化大脑（LHAB）数据库项目；瑞士和1000BRAINS在德国Juelich研究中心。这两个样品的年百分比变化表明，随着时间的推移，皮层厚度稳定至轻微降低。在校正了主要协变量（即基线年龄，性别，教育程度和图像质量）之后，样本差异仅出现在很小的范围内。结果表明，假设使用相同的方法并且存在相似的样本特征，那么跨时间的总体趋势可能会在独立样本上得到概括。