Laboratory of Personality and Cognition, National Institute on Aging, Baltimore, MD 21224, USA.
Hum Brain Mapp. 2012 Sep;33(9):2204-10. doi: 10.1002/hbm.21353. Epub 2011 Aug 30.
Although obesity has been linked to structural brain changes, little is known about its associations with the rates of brain atrophy. We examined associations between global (BMI) and central (waist circumference) midlife obesity and subsequent trajectories of regional brain atrophy in 152 individuals [M (age) = 69 ± 7.8] prospectively followed through the Baltimore Longitudinal Study of Aging; 21 individuals became impaired during follow-up. We report no associations (P > 0.05) between either global or central midlife obesity and subsequent rates of regional brain volume changes against a background of age-related atrophy in older individuals who remained nondemented. When looking at the entire sample, greater decline was observed in the volume of gray matter, precuneus, cingulate and orbito-frontal gyri for globally obese (P < 0.03), even though only data up to the point of dementia diagnosis were included in the analyses (i.e., while still considered clinically normal). Moreover, when trajectories of regional volume changes were examined across the range of BMI and waist circumference values instead of employing a cut-off point to define obesity, a different pattern of results emerged. Overall, our results suggest that midlife obesity may be an important modifier of brain atrophy in individuals who are developing cognitive impairment and dementia, while it has little effect on structural brain integrity in nondemented older adults. Moreover, the discrepancies in findings between studies may be in part due to participant sampling and methodological differences.
尽管肥胖与大脑结构变化有关，但人们对其与大脑萎缩速度的关系知之甚少。我们研究了 152 名参与者（M（年龄）= 69±7.8）中年时全身（BMI）和中央（腰围）肥胖与随后区域性脑萎缩速度之间的关系，这些参与者前瞻性地通过巴尔的摩纵向衰老研究进行了随访；21 名参与者在随访过程中出现了认知障碍。我们报告说，在没有认知障碍的老年人群中，肥胖与年龄相关的萎缩背景下，无论全身性还是中央性中年肥胖都与随后的区域性脑容量变化率没有关联（P＞0.05）。当观察整个样本时，全身性肥胖者的灰质、楔前叶、扣带回和眶额回的体积下降更为明显（P＜0.03），尽管分析中仅包括痴呆诊断前的数据（即，仍被认为是临床正常）。此外，当在 BMI 和腰围值的整个范围内检查区域性体积变化的轨迹而不是使用截止值来定义肥胖时，出现了不同的结果模式。总体而言，我们的结果表明，中年肥胖可能是认知障碍和痴呆患者大脑萎缩的重要调节因素，而对无认知障碍的老年成年人的大脑结构完整性几乎没有影响。此外，研究之间的结果差异可能部分归因于参与者抽样和方法学差异。
