Qiu Xichenhui, Kuang Jiahao, Huang Yiqing, Wei Changning, Zheng Xujuan
Health Science Center, Shenzhen University, No. 1066, Xueyuan Avenue, Nanshan District, Shenzhen, Guangdong Province, 518060, People's Republic of China.
School of Tech X Academy, Shenzhen Polytechnic University, No. 7098, Liuxian Avenue Nanshan District, Shenzhen, Guangdong Province, 518118, People's Republic of China.
BMC Public Health. 2024 Aug 8;24(1):2152. doi: 10.1186/s12889-024-19332-w.
The impact of obesity on cognitive function has engendered considerable interest. Weight-adjusted waist index (WWI) has emerged as a novel and innovative marker of obesity that reflects weight-independent abdominal obesity. However, the association between WWI and cognitive function remains unclear. To address this gap, the present study aims to explore the relationship between weight-adjusted waist index (WWI) and cognitive performance in older adults.
We conducted a cross-sectional investigation using datasets from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. The study included 3,472 participants (48.59% male, 51.41% female) of various races (Mexican American, Other Hispanic, Non-Hispanic White, Non-Hispanic Black, and Other), with a mean age of 69.95 years (SD = 6.94). Multivariate regression and smoothing curve fitting were used to investigate the linear and nonlinear relationship between WWI and cognitive performance in the following domains: learning and memory, verbal fluency, and processing speed, as measured by Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST), respectively. Subgroup analysis and interaction tests were conducted to examine the stability of this relationship across groups. Machine learning models based on random forests were used to analyze the predictive performance of WWI for cognitive function.
A total of 3,472 participants were included in the analysis. The results revealed significant negative associations between WWI and low scores on the CERAD-WL [-0.96 (-1.30, -0.62)], AFT [-0.77 (-1.05, -0.49)], and DSST [-3.67 (-4.55, -2.79)]. This relationship remained stable after converting WWI to a categorical variable. In addition, this significant negative association was more pronounced in men than women and diminished with advancing age. Non-linear threshold effects were observed, with correlations intensifying between WWI and CERAD-WL when WWI surpassed 12.25, AFT when WWI surpassed 11.54, and DSST when WWI surpassed 11.66.
A higher WWI, indicating increased abdominal obesity, was associated with deficits in learning, memory, verbal fluency, and processing speed among older adults. These findings suggest that abdominal obesity may play a crucial role in cognitive decline in this population. The stronger relationship observed between WWI and cognition in men highlights the need for gender-specific considerations in interventions targeting abdominal obesity. The results demonstrate the importance of interventions targeting abdominal obesity to preserve cognitive performance in older adults.
肥胖对认知功能的影响引发了广泛关注。体重调整腰围指数（WWI）已成为一种反映与体重无关的腹部肥胖的新型肥胖标志物。然而，WWI与认知功能之间的关联仍不明确。为填补这一空白，本研究旨在探讨体重调整腰围指数（WWI）与老年人认知表现之间的关系。
我们使用2011 - 2014年美国国家健康与营养检查调查（NHANES）的数据集进行了一项横断面调查。该研究纳入了3472名参与者（男性占48.59%，女性占51.41%），涵盖不同种族（墨西哥裔美国人、其他西班牙裔、非西班牙裔白人、非西班牙裔黑人以及其他种族），平均年龄为69.95岁（标准差 = 6.94）。采用多元回归和平滑曲线拟合来研究WWI与以下认知领域表现之间的线性和非线性关系：学习与记忆、语言流畅性和处理速度，分别通过阿尔茨海默病注册协会词汇学习子测试（CERAD - WL）、动物流畅性测试（AFT）和数字符号替换测试（DSST）进行测量。进行亚组分析和交互作用测试以检验这种关系在不同组间的稳定性。基于随机森林的机器学习模型用于分析WWI对认知功能的预测性能。
共有3472名参与者纳入分析。结果显示，WWI与CERAD - WL低分[-0.96（-1.30， -0.62）]、AFT低分[-0.77（-1.05， -0.49）]和DSST低分[-3.67（-4.55， -2.79）]之间存在显著负相关。将WWI转换为分类变量后，这种关系仍然稳定。此外，这种显著负相关在男性中比女性更明显，且随着年龄增长而减弱。观察到非线性阈值效应，当WWI超过12.25时，WWI与CERAD - WL之间的相关性增强；当WWI超过11.54时，与AFT之间的相关性增强；当WWI超过11.66时，与DSST之间的相关性增强。
较高的WWI表明腹部肥胖增加，与老年人的学习、记忆、语言流畅性和处理速度缺陷相关。这些发现表明腹部肥胖可能在该人群的认知衰退中起关键作用。在男性中观察到的WWI与认知之间更强的关系凸显了在针对腹部肥胖的干预措施中考虑性别差异的必要性。结果表明针对腹部肥胖的干预措施对于保持老年人认知表现的重要性。
