Defining Metabolically Healthy Obesity: Role of Dietary and Lifestyle Factors

BackgroundThere is a current lack of consensus on defining metabolically healthy obesity (MHO). Limited data on dietary and lifestyle factors and MHO exist. The aim of this study is to compare the prevalence, dietary factors and lifestyle behaviours of metabolically healthy and unhealthy obese and non-obese subjects according to different metabolic health criteria. MethodCross-sectional sample of 1,008 men and 1,039 women aged 45-74 years participated in the study. Participants were classified as obese (BMI ≥30kg/m2) and non-obese (BMI 2). Metabolic health status was defined using five existing MH definitions based on a range of cardiometabolic abnormalities. Dietary composition and quality, food pyramid servings, physical activity, alcohol and smoking behaviours were examined. ResultsThe prevalence of MHO varied considerably between definitions (2.2% to 11.9%), was higher among females and generally increased with age. Agreement between MHO classifications was poor. Among the obese, prevalence of MH was 6.8% to 36.6%. Among the non-obese, prevalence of metabolically unhealthy subjects was 21.8% to 87%. Calorie intake, dietary macronutrient composition, physical activity, alcohol and smoking behaviours were similar between the metabolically healthy and unhealthy regardless of BMI. Greater compliance with food pyramid recommendations and higher dietary quality were positively associated with metabolic health in obese (OR 1.45-1.53 unadjusted model) and non-obese subjects (OR 1.37-1.39 unadjusted model), respectively. Physical activity was associated with MHO defined by insulin resistance (OR 1.87, 95% CI 1.19-2.92, p = 0.006). ConclusionA standard MHO definition is required. Moderate and high levels of physical activity and compliance with food pyramid recommendations increase the likelihood of MHO. Stratification of obese individuals based on their metabolic health phenotype may be important in ascertaining the appropriate therapeutic or intervention strategy.

研究背景：目前学界对于代谢健康型肥胖（metabolically healthy obesity, MHO）的定义尚未达成共识，且关于饮食、生活方式因素与MHO关联的研究数据较为匮乏。本研究旨在依据不同的代谢健康判定标准，对比肥胖与非肥胖人群中代谢健康及代谢异常个体的患病率、饮食相关因素及生活行为方式。
研究方法：本研究纳入1008名男性与1039名年龄介于45至74岁的女性作为横断面研究样本。受试者被分为肥胖组（BMI≥30kg/m²）与非肥胖组（BMI 2），代谢健康状态依据5种已有的代谢健康（metabolic health, MH）判定标准进行定义，这些标准基于一系列心血管代谢异常指标。研究对饮食构成与饮食质量、膳食金字塔食物份数、身体活动、饮酒及吸烟行为进行了评估。
研究结果：不同判定标准下，MHO的患病率差异显著（2.2%至11.9%），女性患病率更高，且整体随年龄增长而升高；不同MHO分类标准之间的一致性较差。在肥胖人群中，代谢健康个体的患病率为6.8%至36.6%；在非肥胖人群中，代谢异常个体的患病率为21.8%至87%。无论BMI分组如何，代谢健康与代谢异常人群的热量摄入、膳食宏量营养素构成、身体活动、饮酒及吸烟行为均无显著差异。在肥胖人群中，更高的膳食金字塔推荐食物依从性与更佳的饮食质量与代谢健康呈正相关（未校正模型中比值比（odds ratio, OR）为1.45~1.53）；在非肥胖人群中，该关联的OR值为1.37~1.39。身体活动与以胰岛素抵抗为判定依据的MHO呈显著相关（OR=1.87，95%置信区间：1.19~2.92，p=0.006）。
研究结论：亟需建立统一的MHO判定标准。中等及高水平的身体活动，以及遵循膳食金字塔饮食推荐，均可提升个体罹患MHO的可能性。基于代谢健康表型对肥胖人群进行分层，或有助于确定合适的治疗或干预方案。