代謝健康與體重與全死因死亡風險之相關性：台灣世代研究

The Association of Metabolically Healthy Status and Body Weight on All-cause Mortality: A Representative Cohort Study in Taiwan

目的：代謝健康的過重/肥胖者(metabolically healthy overweight/obesity, MHOO)定義為過重/肥胖卻沒有代謝異常等因子，如高血壓，糖尿病或高血脂。在先前研究中，MHOO的全死因死亡風險與代謝健康且正常體重(metabolically healthy normal weight, MHNW)者相比，結果分岐，因此本研究目的是使用代謝健康的最新定義，探討MHOO是否與較高的全死因死亡風險相關。

方法：本研究由2002-2015年台灣高血壓，高血糖和高血脂調查的5,763名參與者組成，過重/肥胖定義為BMI (body mass index) ≥24 kg/m2，代謝健康定義為沒有高血壓，糖尿病或高血脂且具有健康的代謝狀態（收縮壓<130 mmHg且舒張壓<85 mmHg，飯前血糖<100 mg/dL，三酸甘油酯< 150 mg/dL，HDL男性>40 mg/dL或女性> 50 mg/dL）；我們使用Cox比例風險回歸模型研究不同BMI與代謝狀態分組與全死因死亡率間的關係。

結果：在經過中位數13.7年的追蹤共621例死亡。在調整共變項後，MHOO (HR 0.94，95% CI 0.59-1.50)與MHNW相比，死亡率無明顯差異。次族群分析和敏感性分析顯示相似結果，而年齡可能是重要的修飾因子(effect modifier)；與老年人相比，小於65歲代謝不健康者即使體重正常，死亡風險仍較高(HR 2.06，95% CI 1.39-3.04)；而老年人體重過輕且代謝不健康其死亡風險顯著升高(HR 2.91，95% CI 1.64-5.17)，但代謝不健康之過重肥胖長者且其風險並未升高。

結論：代謝健康之過重肥胖者並不會增加全死因死亡風險，而小於65歲者即使正常體重也應保持代謝健康的狀態，而體重過輕且代謝不健康之長者更應該值得關注。

 

Objective: The objective of this study was to investigate the impact of metabolically healthy status and body weight on all-cause mortality in Taiwan using an updated definition of metabolic health.

Methods: The cohort comprised 5,763 participants from the Taiwanese Survey on Hypertension, Hyperglycemia, and Hyperlipidemia (TwSHHH) from 2002 to 2015. Overweight/obesity was defined as BMI ≥ 24 kg/m2 and metabolically healthy status was defined as absence of hypertension, diabetes, or hyperlipidemia, combined with a healthy cardiometabolic profile. We used a Cox proportional hazards regression model to investigate the relationship between baseline BMI-metabolic groups and mortality. We also performed subgroup analysis to explore potential effect modifiers.

Results: We observed a total of 621 deaths over a median of 13.7 years of follow-up. Metabolically healthy overweight/obesity (MHOO) (HR 0.94, 95% CI 0.59-1.50) was not associated with elevated risk of all-cause mortality compared with metabolically healthy normal weight (MHNW) after adjusting for covariates. The three BMI groups of metabolically unhealthy all showed a significantly higher risk of mortality. Subgroup analysis showed that age is a significant effect modifier. People less than 65 years old that were metabolically unhealthy had elevated risk of mortality even when they were within normal weight (HR 2.06, 95% CI 1.39-3.04). Among elderly people, those underweight and metabolically unhealthy showed significantly elevated risk (HR 2.91, 95% CI 1.64-5.17), but those metabolically unhealthy and with normal weight or overweight/obesity did not.

Conclusion: MHOO without cardiometabolic risk factors was not associated with increased all-cause mortality. People under 65 years old should maintain a metabolically healthy status even within normal weight. More attention should be paid to the elderly with underweight and metabolically unhealthy status.