Supplementary material from: Chinese adults are more susceptible to effects of overall obesity and fat distribution on cardiometabolic risk factors

Context: The body mass index (BMI) and waist circumference (WC) as diagnostic tools of obesity do not reflect the same level of fat mass and whether obesity leads to various effects on cardiometabolic risk factors among different racial/ethnic population is unknown. Objective: The study aims to address the multicollinearity between BMI and WC by using the residual model approach, and to assess and compare the effects of obesity metrics on cardiometabolic risk factors among different races/ethnicities. Design, setting and participants: Data from a nationally representative sample of Mainland Chinese adults collected in 2010, and data from the National Health and Nutrition Evaluation Survey (NHANES) 2005-2016 were used. By conducting a regression analysis between WC and BMI, the variation of BMI was removed from WC measures and residual of WC was obtained. The associations between obesity metrics and cardiometabolic risk factors were compared among different races/ethnicities by sex. Results: The residual WC was significantly associated with all the cardiometabolic risk factors in Mainland Chinese, and most of the factors in Non-Hispanic White and Non-Hispanic Black adults, but not in the other races/ethnicities. The standardized regression coefficients of the associations between obesity metrics and cardiometabolic factors showed that the obesity metrics had greater impact on systolic blood pressure, diastolic blood pressure and triglyceride in Chinese adults than those of other racial/ethnic groups. Conclusions: Chinese adults are more susceptible to the effects of overall obesity and fat distribution on cardiometabolic risk factors than the other racial/ethnic population.

研究背景：体重指数（body mass index, BMI）与腰围（waist circumference, WC）作为肥胖的诊断工具，无法反映同等水平的体脂量；目前尚不明确在不同种族/族裔人群中，肥胖是否会对心血管代谢危险因素（cardiometabolic risk factors）产生各异的影响。
研究目的：本研究旨在通过残差模型方法（residual model approach）解决BMI与WC之间的多重共线性（multicollinearity）问题，并评估并比较不同种族/族裔人群中各类肥胖指标（obesity metrics）对心血管代谢危险因素的影响。
研究设计、研究场景与研究对象：本研究采用2010年收集的中国内地成年人全国代表性样本数据，以及2005-2016年美国国家健康与营养检查调查（National Health and Nutrition Evaluation Survey, NHANES）的数据。通过开展WC与BMI之间的回归分析，从腰围测量值中剥离BMI的变异成分，得到腰围残差。按性别分层，比较不同种族/族裔人群中肥胖指标与心血管代谢危险因素之间的关联。
研究结果：腰围残差与中国内地成年人的所有心血管代谢危险因素均存在显著关联，与非西班牙裔白人（Non-Hispanic White）和非西班牙裔黑人（Non-Hispanic Black）成年人的多数危险因素存在显著关联，但与其他种族/族裔人群的危险因素无显著关联。肥胖指标与心血管代谢危险因素关联的标准化回归系数显示，中国成年人的肥胖指标对收缩压（systolic blood pressure）、舒张压（diastolic blood pressure）及甘油三酯（triglyceride）的影响程度高于其他种族/族裔人群。
研究结论：相较于其他种族/族裔人群，中国成年人更易受到全身性肥胖及体脂分布异常对心血管代谢危险因素产生的影响。