The relationship of bone mineral density with osteocalcin and bone metabolism index in scoliosis patients secondary to neurofibromatosis type 1

English Keywords:Neurofibromatosis type 1  Scoliosis  Bone mineral density  Osteocalcin  Bone metabolism index

English Abstract:

  【Abstract】 Objectives: To investigate the relationship of bone mineral density(BMD) with osteocalcin(BGP) and serum levels of bone metabolism indexes in scoliosis patients secondary to neurofibromatosis type 1(NF1-S). Methods: From February 2012 to March 2013, 17 NF1-S patients aged 8-18 years old and with the Cobb angle ranging from 40° to 143° were recruited as the case group, while 17 healthy peers ranged 7-19 years old were recruited as the control group. Dual-energy X-ray absorptiometry was used to measure the BMD of two groups. The bone metabolism indexes including BGP, serum alkaline phosphatase(ALP), serum calcium, serum phosphorus, urinary calcium, urinary phosphorus, and urinary creatinine were measured by using electro-chemilumin escence immunoassay and an automatic biochemical analyzer. SPSS 16.0 software was used for data analysis. Independent-sample t test was used to analyze the differences of BMD and bone metabolism indexes between two groups, the relationship between lumbar BMD and bone metabolism was accessed by using Pearson correlation analysis. Results: No difference in terms of age and sex was noted in two groups(P>0.05). The BMD of the lumbar spine and the proximal femur in case group was significantly lower than that of the control group(P<0.05). The levels of BGP(135.6ng/ml), serum calcium(2.59mmol/L), serum phosphorus(1.75mmol/L) and urinary calcium/creatinine(U Ca/Cr, 0.10mg/mg) were significantly higher than those of control group(79ng/ml, 2.45mmol/L, 1.47mmol/l, 0.06mg/mg)(P<0.05). The levels of serum ALP(141.6u/L vs 141.8u/L, t=3.611, P=0.991) and urinary phosphorus/creatinine ration(U P/Cr, 0.47mg/mg vs 0.46mg/mg, t=0.054, P=0.957) showed no significance between two groups(P>0.05). The factors, including BGP(r=-0.916, P=0.000) and U Ca/Cr(r=-0.968, P=0.000), were both negatively related with lumbar BMD. Conclusions: The BMD in NF1-S patients is significantly lower than those of the normal control. The levels of BGP, serum calcium, serum phosphorus and U Ca/Cr in NF1-S patients are higher than that of the normal control. The level of BGP and U Ca/Cr is a more sensitive index to monitor the situation of BMD in NF1-S patients.