BACKGROUND Daily physical activity patterns differ by Alzheimer’s disease (AD) status and might signal cognitive risk. It is critical to understand whether patterns are disrupted early in the AD pathological process. Yet, whether established AD risk markers (β-amyloid (Aβ) or APOE-ε4) are associated with differences in objectively measured activity patterns among cognitively unimpaired older adults is unclear. METHODS Wrist accelerometry, brain Aβ (+/-), and APOE-ε4 genotype were collected in 106 (Aβ) and 472 (APOE-ε4) participants [mean age 76 (SD: 8.5) or 75 (SD: 9.2) years, 60% or 58% women] in the BLSA. Adjusted linear and function-on-scalar regression models examined whether Aβ or APOE-ε4 status was cross-sectionally associated with activity patterns (amount, variability, or fragmentation) overall and by time-of-day, respectively. Differences in activity patterns by combinations of Aβ and APOE-ε4 status were descriptively examined (n=105). RESULTS There were no differences in any activity pattern by Aβ or APOE-ε4 status overall. Aβ+ was associated with lower total amount and lower within-day variability of physical activity overnight and early evening, and APOE-ε4 carriers had higher total amount of activity in the evening and lower within-day variability of activity in the morning. Diurnal curves of activity were blunted among those with Aβ+ regardless of APOE-ε4 status, but only when including older adults with MCI/dementia. CONCLUSIONS Aβ+ in cognitively unimpaired older adults might manifest as lower amount and variability of daily physical activity, particularly during overnight/evening hours. Future research is needed to examine changes in activity patterns in larger samples and by other AD biomarkers.

中文翻译：

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老年人中阿尔茨海默病风险标记的日常体力活动差异

背景技术日常体力活动模式因阿尔茨海默病（AD）状态而异，并且可能预示着认知风险。了解 AD 病理过程早期的模式是否被破坏至关重要。然而，目前尚不清楚已建立的 AD 风险标志物（β-淀粉样蛋白 (Aβ) 或 APOE-ε4）是否与认知未受损的老年人客观测量的活动模式差异相关。方法 收集 106 名 (Aβ) 和 472 名 (APOE-ε4) 参与者的手腕加速度、大脑 Aβ (+/-) 和 APOE-ε4 基因型 [平均年龄 76 (SD: 8.5) 或 75 (SD: 9.2) 岁， BLSA 中有 60% 或 58% 女性]。调整后的线性和标量函数回归模型检查了 Aβ 或 APOE-ε4 状态是否分别与整体和一天中不同时间的活动模式（数量、变异性或碎片）存在横截面相关性。对 Aβ 和 APOE-ε4 状态组合的活动模式差异进行了描述性检查 (n=105)。结果 总体而言，Aβ 或 APOE-ε4 状态的任何活动模式均无差异。 Aβ+ 与夜间和傍晚体力活动总量较低和日内变异性较低有关，APOE-ε4 携带者晚上的活动总量较高，早晨活动的日内变异性较低。无论 APOE-ε4 状态如何，Aβ+ 患者的昼夜活动曲线均变钝，但仅限于患有 MCI/痴呆的老年人。结论 认知未受损的老年人中的 Aβ+ 可能表现为日常体力活动量较低且变异性较低，尤其是在夜间/晚上。未来的研究需要检查更大样本和其他 AD 生物标志物的活动模式的变化。