Kuang Xiaodan, Tian Liuhong, Chen Shulei, Fang Jiaming, Ding Pan, Li Jinghai, Wang Lingfang, Shi Hongying
Department of Epidemiology and Health Statistics, School of Public Health, Wenzhou Medical University, University Town, Chashan, Wenzhou, 325035, Zhejiang, China.
School of Mental Health, Wenzhou Medical University, Wenzhou, China.
BMC Public Health. 2025 Apr 7;25(1):1311. doi: 10.1186/s12889-025-22458-0.
Many studies have explored the association between Body Mass Index (BMI) trajectory and mortality, but the association between BMI trajectory during old age and mortality remains underreported, particularly in the Chinese population. This study aimed to investigate the association between BMI trajectories in older adulthood and all-cause mortality in China, and to analyze potential mediating mechanisms.
We analyzed data from the Chinese Longitudinal Healthy Longevity Survey with latent class growth modeling to identity BMI trajectories at 3 follow-up visits (2008, 2011 and 2014). All-cause mortality was assessed from baseline to July 31,2019. Cox proportional hazard regression was used to estimate the association between BMI trajectories and all-cause mortality.
Among 3676 older adults (female: 52.3%, median (IQR) age was 77 (70, 85) years), after 12,516 person-years of follow-up, 1,331 all-cause deaths were recorded. Three distinct BMI trajectories were identified: low-normal stable trajectory (47.33%), normal slight increase trajectory (44.45%), and overweight to obesity trajectory (8.22%). In the fully adjusted model, compared to the normal slight increase trajectory, the risk of all-cause mortality was significantly increased in the low-normal stable trajectory (HR = 1.39, 95%CI: 1.22, 1.60), while the risk of mortality was not statistically different in the overweight to obesity trajectory (HR = 1.16, 95%CI: 0.83, 1.61). Both stratified and sensitivity analyses confirmed these findings. Mediation analysis suggested that cognitive impairment and lack of leisure activities might partially mediate this association. Threshold analysis indicated that the risk of mortality gradually decreases with increasing BMI when BMI is below 26 kg/m (HR = 0.95, 95%CI: 0.93, 0.97) and then remains stable after 26 kg/m.
Compared with normal slight increase trajectory, low-normal stable BMI trajectory during old age may increase the risk of all-cause mortality. These insights hold significant implications for future health management strategies and interventions, aiming to enhance the overall health status and quality of life among older adults.
许多研究探讨了体重指数（BMI）轨迹与死亡率之间的关联，但老年期BMI轨迹与死亡率之间的关联仍未得到充分报道，尤其是在中国人群中。本研究旨在调查中国老年成年人BMI轨迹与全因死亡率之间的关联，并分析潜在的中介机制。
我们分析了中国健康与养老追踪调查的数据，采用潜在类别增长模型来识别在3次随访（2008年、2011年和2014年）时的BMI轨迹。评估从基线到2019年7月31日的全因死亡率。采用Cox比例风险回归来估计BMI轨迹与全因死亡率之间的关联。
在3676名老年人中（女性：52.3%，年龄中位数（四分位间距）为77（70，85）岁），经过12516人年的随访，记录了1331例全因死亡。识别出三种不同的BMI轨迹：低正常稳定轨迹（47.33%）、正常轻微增加轨迹（44.45%）和超重至肥胖轨迹（8.22%）。在完全调整模型中，与正常轻微增加轨迹相比，低正常稳定轨迹的全因死亡风险显著增加（HR = 1.39，95%CI：1.22，1.60），而超重至肥胖轨迹的死亡风险无统计学差异（HR = 1.16，95%CI：0.83，1.61）。分层分析和敏感性分析均证实了这些发现。中介分析表明，认知障碍和缺乏休闲活动可能部分介导了这种关联。阈值分析表明，当BMI低于26kg/m²时，死亡率风险随BMI升高而逐渐降低（HR = 0.95，95%CI：0.93，0.97），然后在26kg/m²之后保持稳定。
与正常轻微增加轨迹相比，老年期低正常稳定的BMI轨迹可能增加全因死亡风险。这些见解对未来的健康管理策略和干预措施具有重要意义，旨在提高老年人的整体健康状况和生活质量。
