Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
Department of Radiology, Mayo Clinic, Rochester, Minnesota.
J Gerontol A Biol Sci Med Sci. 2018 Aug 10;73(9):1244-1250. doi: 10.1093/gerona/glx240.
The longitudinal association between cerebral amyloid-beta (Aβ) and change in gait, and whether this association is mediated by cortical thickness, has yet to be determined.
We included 439 clinically normal (CN) participants, aged 50-69 years and enrolled in the Mayo Clinic Study of Aging with cerebral Aβ, cortical thickness, and gait measurements. Cerebral Aβ deposition was assessed by Pittsburgh Compound B (PiB)-PET in multiple regions of interest (ROIs) (ie, frontal, orbitofrontal, parietal, temporal, anterior cingulate, posterior cingulate/precuneus, and motor). Cortical thickness was assessed on 3T MRI in corresponding ROIs. Gait parameters (gait speed, cadence, stride length, double support time, and covariance of stance time) were measured with GAITRite. Multivariate-adjusted two level structural equation models were used to examine the longitudinal association between PiB-PET, cortical thickness, and change in gait over a median 15.6 months.
Higher PiB-PET in all ROIs was associated with decreasing cadence and increasing double support time, and in the temporal ROI was associated with declining gait speed. In sex-stratified analyses, higher PiB-PET in all ROIs was associated with declining performance on all gait parameters among women. In contrast, among men, the only association was with higher orbitofrontal ROI PiB-PET and declining cadence. None of the associations were mediated by cortical thickness or attenuated after adjustment of baseline cognition.
Higher PiB-PET was associated with declining gait, particularly among women in this middle-aged CN cohort, independent of cortical thickness and baseline cognitive. Elevated brain Aβ may play a critical role in age-related mobility decline.
脑淀粉样蛋白-β（Aβ）与步态变化的纵向关联，以及这种关联是否由皮质厚度介导，尚未确定。
我们纳入了 439 名年龄在 50-69 岁、临床正常（CN）的 Mayo 诊所衰老研究参与者，他们具有脑 Aβ、皮质厚度和步态测量值。通过多部位感兴趣区（ROI）的匹兹堡化合物 B（PiB）-PET 评估脑 Aβ 沉积（即额、眶额、顶、颞、前扣带、后扣带/楔前叶和运动区）。在相应 ROI 上使用 3T MRI 评估皮质厚度。使用 GAITRite 测量步态参数（步速、步频、步长、双支撑时间和站立时间协方差）。采用多变量调整的两水平结构方程模型来检验 PiB-PET、皮质厚度与中位随访 15.6 个月的步态变化之间的纵向关联。
所有 ROI 的 PiB-PET 越高，与步频降低和双支撑时间增加有关，在颞叶 ROI 与步速下降有关。在性别分层分析中，所有 ROI 的 PiB-PET 越高，与女性所有步态参数的表现下降有关。相比之下，在男性中，唯一的关联是眶额 ROI PiB-PET 较高，步频降低。皮质厚度或基线认知调整后，没有关联被中介或减弱。
在这个中年 CN 队列中，较高的 PiB-PET 与步态下降有关，尤其是女性，独立于皮质厚度和基线认知。大脑 Aβ 升高可能在与年龄相关的运动能力下降中发挥关键作用。
