Memory-related impairments in type 2 diabetes may be mediated by insulin resistance and hyperglycemia. Previous cross-sectional studies have controversially suggested a relationship between metabolic control and a decrease in hippocampal volumes, but only longitudinal studies can test this hypothesis directly. We performed a longitudinal morphometric study to provide a direct test of a possible role of higher levels of glycated hemoglobin with long term brain structural integrity in key regions of the memory system – hippocampus, parahippocampal gyrus and fusiform gyrus. Grey matter volume was measured at two different times – baseline and after ~7 years. We found an association between higher initial levels of HbA1C and grey matter volume loss in all three core memory regions, even in the absence of mild cognitive impairment. Importantly, these neural effects persisted in spite of the fact that patients had significantly improved their glycemic control. This suggests that early high levels of HbA1c might be irreversibly associated with subsequent long-term atrophy in the medial temporal cortex and that early intensive management is critical.

中文翻译：

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没有轻度认知障碍的 2 型糖尿病患者的血糖控制可预测 7 年内大脑记忆区域出现不可逆萎缩

2 型糖尿病中与记忆相关的损害可能是由胰岛素抵抗和高血糖介导的。先前的横断面研究提出了代谢控制与海马体积减少之间的关系，但存在争议，但只有纵向研究才能直接检验这一假设。我们进行了纵向形态测量研究，以直接测试高水平糖化血红蛋白对记忆系统关键区域（海马、海马旁回和梭状回）长期大脑结构完整性的可能作用。在两个不同的时间测量灰质体积——基线和约 7 年后。我们发现 HbA1c 初始水平较高之间存在关联1C即使没有轻度认知障碍，所有三个核心记忆区域的灰质体积也会减少。重要的是，尽管患者的血糖控制得到了显着改善，但这些神经效应仍然存在。这表明早期高水平的 HbA1c 可能与随后的内侧颞叶皮层长期萎缩不可逆转地相关，因此早期强化治疗至关重要。