血清25-羟维生素D水平与老年高脂血症患者死亡率的饱和关联：来自NHANES（2001-2016年）的人群基础研究

25-羟维生素D是人体维生素D的主要储存形式，并被国际公认为衡量人体维生素D状态的最佳指标。关于血清25-羟维生素D（25(OH)D）水平与老年高脂血症患者死亡率之间的相互关系的研究较为缺乏。为弥补这一知识空白，我们分析了来自NHANES的老年高脂血症人群中血清25(OH)D水平与死亡率的关联，同时控制了其他影响因素。本研究旨在阐明血清25(OH)D水平与全因死亡率、心血管疾病（CVD）、恶性肿瘤及其他原因死亡率之间的相关性。分析了2001-2016年NHANES的9,271名参与者的数据，利用Kaplan-Meier曲线和限制三次样条法描绘其相互关系，并采用Cox比例风险模型估算多因素调整后的风险比（HR）。本研究包括9,271名参与者（男性占43.28%），平均年龄为69.58岁，随访平均时间为88.37个月。Kaplan-Meier曲线显示，较低的血清25(OH)D水平与全因死亡率、心血管死亡率、恶性肿瘤死亡率以及其他原因死亡风险增加有关。这一负相关关系通过Cox比例风险模型得到进一步确认。此外，限制三次样条不仅揭示了这种负相关，还强调了血清25(OH)D的饱和水平。此外，亚组分析显示，血清25(OH)D水平与全因死亡率的负相关在非肥胖和吸烟人群中更为显著，与其他原因死亡的负相关在非肥胖人群中更为强烈。在老年高脂血症患者中，血清25(OH)D水平与特定原因死亡和全因死亡均呈负相关关系，而且这种负相关关系存在阈值效应。

25-hydroxyvitamin D is the body's main storage form of vitamin D and is internationally recognized as the best indicator of vitamin D status in the human body. There is a scarcity of research investigating the interrelationship between serum 25-hydroxyvitamin D (25(OH)D) levels and mortality among elderly individuals with hyperlipidemia. To address this knowledge gap, we examined the association between serum 25(OH)D levels and mortality in an older hyperlipidemic population from NHANES, while controlling for other influential factors. The study sought to elucidate the correlation between serum 25(OH)D levels and mortality about all-cause mortality, cardiovascular disease (CVD), malignant neoplasms, and mortality from other causes.The data from NHANES 2001-2016, including 9,271 participants were analyzed to examine the association between serum 25(OH)D levels and mortality. The interrelationship was illustrated using Kaplan-Meier curves and restricted cubic splines, while the Cox proportional hazards model was utilized to estimate the multifactor adjusted hazard ratio (HR).This study included 9,271 participants (43.28% male) with an average age of 69.58 years, and the average duration of participant follow-up was 88.37 months. Kaplan-Meier curves demonstrated that lower serum 25(OH)D levels were associated with increased risks of all-cause mortality, cardiovascular mortality, malignant neoplasm mortality, and mortality from other causes. This negative association was further confirmed by the Cox proportional hazards models. Additionally, restricted cubic splines not only revealed this negative association but also highlighted the saturated serum 25(OH)D levels. Moreover, subgroup analyses indicated that the inverse correlation between serum 25(OH)D levels and all-cause mortality was more pronounced in the non-obese and smoking population. And the inverse correlation with mortality from other causes was even stronger in the non-obese population.In the elderly population with hyperlipidemia, 25(OH)D serum levels were negatively correlated with both cause-specific mortality and all-cause mortality. Moreover, there was a threshold effect in this negative association.