石家庄市夏季汉族4月龄至14岁健康儿童血清25-羟维生素D和甲状旁腺素的关系

目的探讨汉族儿童青少年夏季血清25-羟维生素D(25OHD)和甲状旁腺素(PTH)水平的关系,以及儿童青少年是否存在PTH进入平台期的血清25OHD拐点值。方法河北医科大学第二医院儿科生长发育门诊于2011年6~8月及2012年6~8月向社会招募4月龄至14岁健康儿童青少年。分为1岁、~3岁、~6岁、~10岁和~14岁组。分别采用酶联免疫法和化学发光免疫分析法测定血清25OHD和全段PTH水平。对血清25OHD与PTH水平的关系分别行直线、二次多项式、指数和对数拟合等,计算血清PTH水平进入平台期的血清25OHD阈值。结果共招募632名健康儿童青少年,男童372名,女童260名。1血清25OHD和PTH水平的中位数(P25,P75)分别为56.7(42.2,76.4)nmol·L-1和2.5(2.0,3.3)pmol·L-1。2血清25OHD与PTH在除~10岁组外的其余年龄组中均呈负相关。3二次多项式回归方程能较好反映血清25OHD和PTH之间的曲线关系。回归方程为PTH(pmol·L-1)=4.2698-0.0352·25OHD+0.0002·25OHD2,R2=0.0684。PTH进入平台期时血清25OHD的拐点值为88 nmol·L-1,对应的PTH值为2.72 pmol·L-1。结论 4月龄至14岁汉族儿童青少年的血清25OHD和PTH水平呈负相关,且理想的血清25OHD水平可能为88 nmol·L-1。

Relationship between serum 25-hydroxyvitamin D and parathyroid hormone of Chinese Han children aged from 4 months to 14 years during summer in Shijiazhuang city

Objective To explore the relationship between serum 25-hydroxyvitamin D (25OHD) and intact parathyroid hormone (PTH) of Chinese children aged from 4 months to 14 years and to examine a threshold value of serum 25OHD at which serum iPTH levels decreased and reached a plateau. Methods The subjects aged from 4 months to 14 years who came to division of nutrition, growth and development & endocrinology of department of pediatrics, Second Hospital of Hebei Medical University during June to August in 2011 and 2012 for health examination were recruited on the basis of informed consent. Fasting venous blood was collected and serum 25OHD, PTH, alkaline phosphates (ALP), calcium (Ca) and phosphorus (P) were assayed. Data were analyzed by using SPSS 13.0 software. Multiple linear regressions were used between variables besides bivariate correlations. Linear and quadratic polynomial fitting, cubic polynomial fitting and Loess fitting were used to assess the relationship between 25OHD and iPTH respectively. Results A total of 632 subjects including 372 boys and 260 girls were recruited. ①Serum 25OHD was inversely correlated with serum PTH (R=-0.246, P<0.001). Serum 25OHD was inversely correlated with age (R=-0.643, P<0.001). Serum PTH was positively correlated with age (R=0.15, P<0.001). ②According to the scatter plot of 25OHD and PTH, the quadratic polynomial fitting was the best one to describe the relation. The equation was PTH(pmol·L-1)=4.2698-0.0352D＋0.0002D2(R2=0.068 4). D referred to serum 25OHD levels (nmol·L-1). When differential coefficient equaled to 0, the 25OHD level was 88 nmol·L-1. So 88 nmol·L-1 was considered as the cutoff value at which serum PTH levels decreased and reached a plateau. When serum 25OHD was 88 nmol·L-1, the serum PTH level was 2.72 pmol·L-1. Conclusion In 4 months to 14 years old Chinese children, serum 25OHD inversely correlates with serum iPTH. The ideal serum 25-hydroxyvitamin D levels may be 88 nmol·L-1 for Chinese infants, children and adolescents.