Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China.
Department of Neurology, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China.
J Alzheimers Dis. 2023;96(2):657-668. doi: 10.3233/JAD-230575.
Sedentary behavior is associated with cognitive impairment, but the neuropathological mechanisms underlying their associations are poorly understood.
To investigate the associations of accelerometer-measured sedentary behavior patterns with brain structure and cognition, and further to explore the potential mechanisms.
This community-based study included 2,019 older adults (age≥60 years, 59% women) without dementia derived from participants in the baseline examination of MIND-China (2018-2020). We assessed sedentary parameters using an accelerometer and cognitive function using a neuropsychological test battery. Structural brain markers were assessed on the structural brain MRI scans in a subsample (n = 1,009). Data were analyzed using the general linear, isotemporal substitution, and mediation models.
In the total sample (n = 2,019), adjusting for multiple covariates and moderate-to-vigorous-intensity physical activity, longer mean sedentary bout duration was linearly related with lower z-scores of global cognition, verbal fluency, and memory (ptrend < 0.05), whereas greater total sedentary time was linearly associated with lower z-scores of global cognition, verbal fluency, and memory only among individuals with long sedentary time (>10 h/day) (ptrend < 0.05); Breaking up sedentary time with same amount of light-intensity physical activity was significantly associated with higher verbal fluency and memory z-scores (p < 0.05). In the MRI subsample (n = 1,009), separately entering structural brain MRI markers into the mediation models substantially attenuated the associations of mean sedentary bout duration with global cognition, verbal fluency, and memory z-scores.
Prolonged uninterrupted sedentary time is associated with poor global cognition, memory, and verbal fluency among rural older adults, and structural brain markers could partially mediate the association.
久坐行为与认知障碍有关，但它们之间关联的神经病理学机制尚不清楚。
探究加速度计测量的久坐行为模式与大脑结构和认知之间的关联，并进一步探讨潜在的机制。
本研究为基于社区的研究，共纳入 2019 名年龄≥60 岁的老年人（59%为女性），这些老年人均来自 MIND-China 研究的基线检查阶段（2018-2020 年）。我们使用加速度计评估久坐参数，使用神经心理学测试工具包评估认知功能。在子样本（n=1009）中对结构脑标记物进行了结构脑 MRI 扫描评估。使用一般线性模型、等时替代模型和中介模型进行数据分析。
在总样本（n=2019）中，在调整了多种协变量和中高强度体力活动后，较长的平均久坐时间与整体认知、言语流畅性和记忆的 z 评分呈线性相关（ptrend<0.05），而较长的总久坐时间与整体认知、言语流畅性和记忆的 z 评分仅在长时间久坐（>10 h/d）的个体中呈线性相关（ptrend<0.05）；将久坐时间打断并以相同的低强度体力活动替代，与言语流畅性和记忆的 z 评分显著升高相关（p<0.05）。在 MRI 子样本（n=1009）中，分别将结构脑 MRI 标志物纳入中介模型，显著减弱了平均久坐时间与整体认知、言语流畅性和记忆 z 评分的关联。
在农村老年人中，长时间不间断的久坐与整体认知、记忆和言语流畅性较差有关，而结构脑标志物可能部分介导了这种关联。
