Birdsill Alex Cole, Oleson Stephanie, Kaur Sonya, Pasha Evan, Ireton Adele, Tanaka Hirofumi, Haley Andreana
Department of Psychology, The University of Texas at Austin, Austin, Texas.
Department of Kinesiology & Health Education, The University of Texas at Austin, Austin, Texas.
Hum Brain Mapp. 2017 Jul;38(7):3337-3344. doi: 10.1002/hbm.23576. Epub 2017 Apr 8.
The aging U.S. population and the recent rise in the prevalence of obesity are two phenomena of great importance to public health. In addition, research suggests that midlife body mass index (BMI) is a risk factor for dementia, a particularly costly disease, in later life. BMI could influence brain health by adversely impacting cerebral white matter. Recently, greater BMI has been associated with lower white matter fractional anisotropy (FA), an index of tissue microstructure, as measured by diffusion-tensor imaging in midlife. The aim of this study was to investigate the role of abdominal obesity, the most metabolically active adipose tissue compartment, and white matter microstructure in midlife. Community dwelling participants (N = 168) between the ages of 40-62 underwent MRI scanning at 3T and a general health assessment. Inferences were made on whole brain white matter tracts using full-tensor, high-dimension normalization, and tract-based spatial statistics. Higher waist circumference was associated with higher FA, indicating more directional diffusion in several white matter tracts controlling for age, sex, triglycerides, systolic blood pressure, fasting glucose, and HDL-cholesterol. Post hoc analysis revealed that greater waist circumference was associated with lower axial diffusivity, indicating lower parallel diffusion; lower radial diffusivity, indicating lower perpendicular diffusion; and lower mean diffusivity, indicating restricted diffusion. This is the first study to report a positive relationship between obesity and FA, indicating a more complicated view of this relationship in the aging brain. Hum Brain Mapp 38:3337-3344, 2017. © 2017 Wiley Periodicals, Inc.
美国人口老龄化以及近期肥胖患病率的上升是对公共卫生极为重要的两个现象。此外，研究表明中年体重指数（BMI）是晚年患痴呆症（一种代价高昂的疾病）的风险因素。BMI可能通过对脑白质产生不利影响来影响大脑健康。最近，较高的BMI与较低的白质分数各向异性（FA）相关，FA是一种组织微观结构指标，通过中年期的扩散张量成像测量得到。本研究的目的是调查腹部肥胖（代谢最活跃的脂肪组织区域）和中年白质微观结构的作用。年龄在40 - 62岁之间的社区居住参与者（N = 168）接受了3T磁共振成像扫描和全面的健康评估。使用全张量、高维归一化和基于束的空间统计学对全脑白质束进行推断。较高的腰围与较高的FA相关，这表明在控制年龄、性别、甘油三酯、收缩压、空腹血糖和高密度脂蛋白胆固醇的情况下，几个白质束中的扩散方向性更强。事后分析显示，较大的腰围与较低的轴向扩散率相关，表明平行扩散较低；较低的径向扩散率，表明垂直扩散较低；以及较低的平均扩散率，表明扩散受限。这是第一项报告肥胖与FA呈正相关的研究，表明在衰老大脑中这种关系更为复杂。《人类大脑图谱》38:3337 - 3344，2017年。© 2017威利期刊公司。
