Childhood Study Of Optimal Levels Of Vitamin D And Vitamin D Nutritional Status Of Children In Nanjing Investigation

[Objective] Up to now, the optimal level of 25-(OH)D is still unclear for bone health, so we carried out this study to explore the optimal 25-(OH)D concentration for bone healthy in children.[Methods] All subjects (76 are healthy, 66 are suffering from respiratory system infection) aged 0-10 years were enrolled in this study during 2007/12-2008/03. Venous blood samples were collected from subjects before breakfast in the morning and the levels of serum 25-(OH)D, intact parathyroid hormone (PTH), bone-specific alkaline phosphatase (BAP), calcium(Ca), phosphorus(P) were determined by ELISA.[Results] The response curves of 25-(OH)D concentration vs. PTH concentration, 25-(OH)D concentration vs. BAP concentration show that, when 25-(OH)D≤50nmol/L, PTH and BAP are both significantly and negatively correlated with 25-(OH)D (25-(OH)D vs. PTH, r=-0.864, P<0.01; 25-(OH)D vs. BAP, r=-0.856, P<0.01). When 25-(OH)D>50-60nmol/L, PTH and BAP levels keep almost steady. The response curve of 25-(OH)D vs. Ca×P product shows that, when 25-(OH)D≤50nmol/L, Ca×P product rises as 25-(OH)D increases(but the correlation analysis shows r=0.037, P>0.05), when 25-(OH)D>50-60nmol/L, Ca×P product keeps in a certain level.[Conclusion] The optimal 25-(OH)D level for bone health may be 50-60nmol/L in children aged 0-10 years in Nanjing area. [Objective] To get the data of serum 25-hydroxyvitamin D[25-(OH)D], parathyroid hormone(PTH), bone-specific alkaline phosphatase(BAP) levels of 0-10 years old children in Nanjing city, and to get some potentially useful data for the clinical practice on vitamin D supplements.[Methods] All subjects (76 are healthy, 66 are suffering from respiratory system infection) aged 0-10y were recruited during 2007/12-2008/03. Venous blood samples were collected from subjects before breakfast in the morning and the levels of serum 25-(OH)D, intact parathyroid hormone (PTH), bone-specific alkaline phosphatase (BAP), calcium(Ca), phosphorus(P) were determined by ELISA. [Results] The average level of serum 25-(OH)D is 81.3±29.3 nmol/L(mean±SD) in all healthy children, vitamin D deficiency [25-(OH)D<50nmol/L] is observed in 10.5% of these children. The levels of serum 25-(OH)D, PTH, BAP fluctuate with increasing of age, respectively. The level of serum 25-(OH)D is 65.6±32.3 nmol/L in sick children, significantly low than that of healthy children(P<0.05).[Conclusion] The vitamin D status of children in Nanjing area is quite well. With increasing of age, the level of serum 25-(OH)D significantly fluctuates, ascending first and descending later; On the contrary, the levels of serum PTH and BAP descend first and ascend later; Sick children have significantly lower level of serum 25-(OH)D than healthy children.