論文丨低BMI相較于高BMI增加老年2型糖尿病患者死亡風險：一項上海市糖尿病管理隊列研究

論文發表

近日，由我院王帆教授（共同通訊作者）、公共衛生學院博士生莫鴻飛（共同第一作者），以及上海市疾病預防控制中心施燕主任（共同通訊作者）、嚴青華副主任醫師（共同第一作者）等專家合作完成的論文“Increased mortality risk with lower versus higher BMI in older adults with T2DM: a Shanghai diabetes management cohort study”發表于期刊《BMC Geriatrics》（SCIE/SSCI雙收錄，JCR Q1）。該期刊是老年學/老年醫學領域權威期刊，聚焦老年人群常見疾病的流行病學、臨床管理及公共衛生干預，涵蓋衰老相關慢性病的預防、診療及預后研究。本研究成果體現了王帆教授團隊在社區體重管理方面的積極探索。

本研究基于上海市糖尿病管理隊列，系統探討了老年2型糖尿病患者中BMI與全因死亡風險的劑量－反應關系，進一步驗證了“肥胖生存悖論”在該人群中的存在，為老年糖尿病患者的體重管理提供了新的科學依據。研究發現，老年T2DM患者的BMI與全因死亡風險呈U型關系，最低風險點對應BMI為22.68。低BMI（＜22.68）顯著增加死亡風險，而高BMI雖與死亡風險正相關，但效應較弱。進一步分析顯示，BMI低于20.41或21.55的人群生存概率顯著下降，而高于24.95或23.81者與參考組無顯著差異。研究提示，在老年2型糖尿病患者中，低BMI帶來的風險遠高于高BMI，體重管理策略應優先避免低BMI，而非盲目追求減重。該成果為中國老年糖尿病人群BMI管理提供了具體的參考閾值（22.68）和安全區間（20.41~24.95），對優化個體化干預策略具有重要臨床與公共衛生意義。

作者/Authors

Hongfei Mo1,2?, Qinghua Yan3?, Yining Wang1, Minna Cheng3, Huiting Yu4, Shuyue Sun1,2, Fei Wu3, Qi Li4, Ziyang Yao2, Haoyu Ge2, Fan Wang2,5*, Yan Shi3*

1. School of Public Health, Fudan University, Shanghai, P.R.China

2. Fudan Development Institute, Fudan University, Shanghai, P.R.China

3. Institute for Chronic Non-communicable Diseases Control, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, P.R.China

4. Institute of Health Information, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, P.R.China

5. Health Communication Institute, Fudan University, Shanghai, P.R.China

?Hongfei Mo and Qinghua Yan contributed equally as co-first authors.

*Correspondence to Yan Shi or Fan Wang

摘要/Abstract

目的本研究旨在探討上海市老年2型糖尿?。═2DM）患者身體質量指數（BMI）與全因死亡率之間的關系，確定最佳BMI閾值及安全區間，并分析低BMI和高BMI對死亡風險的非對稱性影響。

方法這項大規模社區隊列研究基于上海市疾病預防控制中心的糖尿病管理隊列。共納入372,829名年齡≥60歲的T2DM患者，隨訪時間為2020年5月1日至2024年12月31日，中位隨訪期為19個月。BMI通過標準化測量及自我報告的身高和體重（kg/m2）計算得出。全因死亡率數據與上海市死亡登記系統進行匹配。協變量包括性別、年齡、婚姻狀況、教育水平、吸煙、飲酒和體力活動。統計分析采用限制性立方樣條（RCS）分析來探索BMI與死亡風險之間的劑量－反應關系，并確定最佳截斷值。進一步使用Cox回歸和Kaplan-Meier（KM）生存曲線比較不同BMI組別，以評估風險差異。采用±5%和±10%的BMI區間驗證風險梯度，并對協變量進行調整。顯著性水平設定為α=0.05。

結果RCS曲線顯示，BMI與全因死亡率之間呈U型關系，確定BMI為22.68時為死亡風險最低點（協變量調整模型，非線性檢驗P＜0.001）。風險呈現非對稱性：低BMI（＜22.68）顯著增加死亡風險（HR=0.86，95%CI：0.82~0.88，P＜0.001），而高BMI與死亡風險呈正相關（HR=1.01，95%CI：1.01~1.02，P＜0.001），但效應量較弱。分層分析顯示，與參考組（21.55~23.81）相比，BMI＜21.55（-5%區間）的生存概率顯著降低（P＜0.001），而BMI＞23.81（+5%區間）的生存概率與參考組在KM曲線上無顯著差異。同樣，與參考組（20.41~24.95）相比，BMI＜20.41（-10%區間）的生存概率顯著降低（P＜0.001），而BMI＞24.95（+10%區間）在KM曲線上與參考組相比無顯著差異。

結論在老年T2DM患者中存在肥胖生存悖論，低BMI顯著增加死亡風險，而高BMI的保護作用可能部分抵消其代謝危害，導致其風險效應量較低。這些發現提示，老年T2DM患者的體重管理策略應優先考慮避免低BMI，而非激進地減重。

ObjectiveThis study aims to investigate the relationship between body mass index (BMI) and all-cause mortality among older adults with type 2 diabetes mellitus (T2DM) in Shanghai, seeking to determine the optimal BMI threshold and safe range, as well as to analyze the asymmetric effects of low and high BMI on mortality risk.

MethodsThis large-scale community cohort study is based on the diabetes management cohort from the Shanghai Municipal Center for Disease Control and Prevention. A total of 372,829 T2DM patients age ≥60 were included, with a follow-up period from May 1, 2020, to Dec 31, 2024, and a median follow-up of 19 months. BMI was calculated using standardized measurements and self-reported height and weight (kg/m2). All-cause mortality data were matched from the Shanghai Death Registry System. Covariates included sex, age, marital status, education level, smoking, alcohol, and physical activity. Statistical analysis utilized Restricted Cubic Spline (RCS) analysis to explore the dose-response relationship between BMI and mortality risk, identifying the optimal cutoff point. BMI groups were further compared using Cox regression and Kaplan-Meier (KM) survival curves to assess risk differences. BMI intervals of ±5% and ±10% were used to verify risk gradients, with adjustments for covariates. The significance level was set at α=0.05.

ResultsThe RCS curve revealed a U-shaped relationship between BMI and all-cause mortality, identifying a BMI of 22.68 as the point of lowest mortality risk (covariates adjusted model, P for nonlinear <0.001). The risk was asymmetric: a low BMI (22.68) significantly increased mortality risk (HR=0.86, 95%CI: 0.82~0.88, P <0.001), while high BMI was positively correlated with mortality risk (HR=1.01, 95%CI: 1.01~1.02, P <0.001) but with a weaker effect size. Stratified analysis showed that BMI <21.55 (-5% interval) was associated with significantly lower survival probability compared to the reference group (21.55~23.81) (P <0.001), whereas BMI >23.81 (+5% interval) had survival probabilities that were not significantly different from those of the reference group on the KM curve. Similarly, BMI <20.41 (-10% interval) had significantly lower survival probability than the reference group (20.41~24.95) (P <0.001), while BMI >24.95 (+10% interval) showed no statistically significant difference compared to the reference group on the KM curve.

ConclusionsThere is an obesity survival paradox among T2DM older adults, with low BMI significantly increasing mortality risk, while the protective effects of high BMI may partially counterbalance its metabolic harms, resulting in a lower effect size of risk. These findings suggest that weight management strategies for older adults with T2DM should prioritize the avoidance of low BMI over aggressive weight reduction.

關鍵詞/Key Words

全因死亡率；身體質量指數；肥胖悖論；老年2型糖尿??；限制性立方樣條；上海隊列

All-cause mortality; Body mass index (BMI); Obesity paradox; Type 2 diabetes mellitus (T2DM) in older adults; Restricted cubic splines (RCS); Shanghai cohort

全文鏈接/Link

https://link.springer.com/article/10.1186/s12877-026-07017-5

來源｜BMC Geriatrics