中国中老年人血清维生素D与甲状旁腺素浓度的关系

Relationship between vitamin D and parathyroid hormone in Chinese elderly people

目的探讨中国50岁及以上中老年人血清25-羟基维生素D[25(OH)D]浓度与甲状旁腺素浓度的关系,初步探索中老年人维生素D适宜营养状况的界值并应用于该人群代谢综合征的风险预测。方法从2015年中国成人慢性病与营养监测生物样本库中按年龄、性别分层随机抽取50岁及以上的成年人样本750例,采用问卷调查收集基本信息(年龄、性别、季节等)并进行体格测量。血清中25(OH)D浓度检测采用液相色谱-质谱联用法,白细胞介素-6、甲状旁腺素含量测定采用电化学发光法,磷、白蛋白、肌酐等指标的测定采用全自动生化分析仪。采用多重线性回归筛选影响25(OH)D浓度、甲状旁腺素含量的相关因素,并通过广义加性模型进行校正,采用局部加权散点平滑法预测甲状旁腺素的拐点值,以非线性最小二乘和分段线性回归确定甲状旁腺素达到平台期的25(OH)D界值。以上述界值为切点,采用多因素Logistic回归分析中老年人不同25(OH)D切点与代谢综合征的关系。结果中国50岁及以上中老年人血清25(OH)D缺乏的界值为19.62 ng/mL,充足的界值为28.44 ng/mL。校正性别、年龄、地区、季节等混杂因素后,25(OH)D充足(≥28.44 ng/mL)能够显著降低本研究中老年人代谢综合征风险[OR=0.617(0.439~0.869)]。按性别分层分析,经局部加权散点平滑法初步获得甲状旁腺素处于平台期时25(OH)D的浓度范围,男性、女性分别为20.03~28.43、13.12~26.33 ng/mL;但未能获得有统计学意义的切点。结论本研究观察到中国50岁以上中老年人血清25(OH)D浓度为19.62~28.44 ng/mL时可使甲状旁腺素达到最大抑制,该界值可能因性别而异。更充足的维生素D界值水平(28.44 ng/mL)对该人群的代谢综合征风险具有保护作用。

OBJECTIVE To explore the relationship between serum 25-hydroxyvitamin D(25(OH)D)and serum parathyroid hormone(PTH)level in Chinese people aged 50 years and above,and to probe the optimum threshold for vitamin D sufficiency preliminarily,and apply this threshold to predict the risk of metabolic syndrome(Mets)in this population.METHODS A total of 750 serum samples were selected from the biological samples’bank of Chinese Chronic Diseases and Nutritional Survey(CCDNS,2015-2017)by stratified sampling,basic information(including age,gender,season,etc.)were collected from questionnaire and physical measurement of the subjects were conducted unified.Serum 25(OH)D concentration was determined by high performance liquid chromatography tandem mass spectrometer,and PTH and interleukin-6(IL-6)were detected by electrochemiluminescence method.Phosphorus,albumin(Alb),creatinine(Cr)in blood were detected by automatic biochemical analyzer.Factors affecting the concentration of 25(OH)D and PTH were found by multiple linear regression and adjusted by generalized additive model separately,threshold was predicted by locally weighted regression and smoothing scatterplot,abbreviated as LOESS,and the exact threshold of 25(OH)D was found when PTH reached the plateau by nonlinear least squares estimation and segmented regression.Relationship between 25(OH)D and Mets was analyzed by multivariate logistic regression using the different cut-off points in Chinese elderly people.RESULTS Reference threshold for vitamin D deficiency in Chinese elderly people can be preliminarily discovered as serum total 25(OH)D was 19.62 ng/mL,and 28.44 ng/mL can be used as reference threshold for sufficient vitamin D.Sufficient 25(OH)D(≥28.44 ng/mL)could reduce the risk of Mets significantly(OR=0.617(0.439-0.869))after adjusting for confounding factors such as sex,age,region,season,ect.A plateau in PTH was observed at a 25(OH)D concentration of 20.03-28.43 ng/mL for male whereas 13.12-26.33 ng/mL for female by gender stratification analysis,but no cut-off point was obtained statistically.CONCLUSION Reference threshold for vitamin D sufficiency in Chinese elderly people was preliminarily observed in the range of 19.62-28.44 ng/mL when PTH was maximally inhibited,and the threshold may vary with gender.Applying the threshold we also found that more sufficient levels of vitamin D were protective against Mets in this population.