血清维生素C浓度与肾结石患病率之间的 U型关系：基于NHANES的横断面研究

U-Shaped Relationship between Serum Vitamin C Concentration and Prevalence of Kidney Stones: A Cross-Sectional Study from NHANES

摘要: 目的：关于维生素C水平与肾结石发生风险之间的关系仍存在争议。本研究旨在探讨血清维生素C浓度与肾结石发生之间的关联。方法：本研究进行了横断面分析，使用2017~2018年国家健康与营养调查的数据，共有4932名参与者。血清维生素C浓度采用超高效液相色谱法测定，研究对象肾结石患病率通过问卷调查获得。研究采用分段回归分析确定血清维生素C的临界值为1.69 mg/dL，并通过对数似然比检验验证了该阈值的显著性。然后，构建了三种logistic回归模型，以探讨过量(≥1.69 mg/dL)与非过量的血清维生素C对肾结石的影响，并进行分层分析以评估其在不同人群中的适用性。结果：参与者中肾结石的患病率为10.22%。研究发现，血清维生素C浓度与肾结石患病率之间存在U形关系，1.69 mg/dL被确定为临界值。当血清维生素C浓度低于该临界值时，维生素C每增加一个单位可使肾结石发生率降低29%；而当浓度超过该临界值时，肾结石患病率与血清维生素C浓度呈正相关。结论：本研究发现，血清维生素C浓度与肾结石风险之间呈现非线性关系，表明无论是过高还是过低的血清维生素C水平都与肾结石的风险相关。这些结果强调了维持适当的血清维生素C水平可能在肾结石预防中具有重要性，但我们的结论尚需通过进一步的临床研究加以验证。

Abstract: Objective: The relationship between vitamin C levels and the risk of kidney stone formation remains controversial. This study aimed to investigate the association between serum vitamin C concentration and kidney stone occurrence. Methods: A cross-sectional analysis was conducted using data from the 2017~2018 National Health and Nutrition Examination Survey, comprising 4932 participants. Serum vitamin C concentrations were measured by ultra performance liquid chromatography. The prevalence of kidney stones among participants was determined through self-reported questionnaires. Segmented regression analysis identified a serum vitamin C threshold value of 1.69 mg/dL, the significance of which was confirmed by a log-likelihood ratio test. Subsequently, three logistic regression models were constructed to examine the effects of excess (≥1.69 mg/dL) versus non-excess serum vitamin C on kidney stones. Stratified analyses were conducted to evaluate the applicability of these models across different populations. Results: The prevalence of kidney stones among participants was 10.22%. A U-shaped relationship was observed between serum vitamin C concentration and kidney stone prevalence, with a threshold identified at 1.69 mg/dL. Below this threshold, each unit increase in serum vitamin C concentration decreased kidney stone incidence by 29%. Conversely, above this threshold, kidney stone prevalence was positively correlated with serum vitamin C concentrations. Conclusions: This study identified a nonlinear relationship between serum vitamin C concentration and kidney stone risk, indicating that both excessively high and low serum vitamin C levels are associated with increased risk. These findings underscore the importance of maintaining appropriate serum vitamin C levels for kidney stone prevention; however, further clinical studies are required to validate our conclusions.