Objective

To explore the value of olfactory identification deficits as a predictor of cerebral β-amyloid status and other markers of brain health in cognitively normal adults aged ~ 70 years.

Methods

Cross-sectional observational cohort study. 389 largely healthy and cognitively normal older adults were recruited from the MRC National Survey of Health and Development (1946 British Birth cohort) and investigated for olfactory identification deficits, as measured by the University of Pennsylvania Smell Identification Test. Outcome measures were imaging markers of brain health derived from 3 T MRI scanning (cortical thickness, entorhinal cortex thickness, white matter hyperintensity volumes); ¹⁸F florbetapir amyloid-PET scanning; and cognitive testing results. Participants were assessed at a single centre between March 2015 and January 2018.

Results

Mean (± SD) age was 70.6 (± 0.7) years, 50.8% were female. 64.5% had hyposmia and 2.6% anosmia. Olfaction showed no association with β-amyloid status, hippocampal volume, entorhinal cortex thickness, AD signature cortical thickness, white matter hyperintensity volume, or cognition.

Conclusion and relevance

In the early 70s, olfactory function is not a reliable predictor of a range of imaging and cognitive measures of preclinical AD. Olfactory identification deficits are not likely to be a useful means of identifying asymptomatic amyloidosis. Further studies are required to assess if change in olfaction may be a proximity marker for the development of cognitive impairment.

中文翻译：

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嗅觉测试不能预测 1946 年英国出生队列中的 β-淀粉样蛋白、神经退行性变或血管病理学的 MRI 测量。

客观的

探讨嗅觉识别缺陷作为 70 岁认知正常成年人脑 β-淀粉样蛋白状态和其他脑健康标志物的预测价值。

方法

横断面观察性队列研究。从 MRC 国家健康与发展调查（1946 年英国出生队列）招募了 389 名基本健康且认知正常的老年人，并根据宾夕法尼亚大学气味识别测试测量了嗅觉识别缺陷。结果测量是来自 3 T MRI 扫描的大脑健康成像标志物（皮质厚度、内嗅皮质厚度、白质高信号体积）；¹⁸ F florbetapir 淀粉样蛋白-PET 扫描；和认知测试结果。参与者在 2015 年 3 月至 2018 年 1 月期间在一个中心接受评估。

结果

平均 (± SD) 年龄为 70.6 (± 0.7) 岁，50.8% 为女性。64.5% 有嗅觉减退和 2.6% 嗅觉丧失。嗅觉与 β-淀粉样蛋白状态、海马体积、内嗅皮层厚度、AD 特征皮层厚度、白质高信号体积或认知无关。

结论和相关性

在 70 年代初，嗅觉功能并不是临床前 AD 的一系列成像和认知测量的可靠预测指标。嗅觉识别缺陷不太可能是识别无症状淀粉样变性的有用方法。需要进一步的研究来评估嗅觉的变化是否可能是认知障碍发展的接近标志。