Reference and Influential Factors of Serum Bone Markers in Chinese Adolescents

This study aimed to establish reference ranges of bone markers in Chinese adolescents between the age of 12 and 16, and to search these markers' characteristics and influential factors. Personal information and fasting blood samples were collected from 174 healthy adolescents in Northeast China. Serum levels of PINP, ALP, β-CrossLaps, calcium, phosphate, PTH, 25(OH)D and TSH were measured. Reference ranges were established for PINP [(85.55-2,028.75)ng/ml], ALP [(53.88-463.63)U/L], β-CrossLaps [(0.16-1.19)ng/ml], calcium [(2.35-2.70)mmol/L], phosphate [(1.17-2.06)mmol/L] and PTH [(2.64-43.36)μg/L] in this population. We observed that bone formation markers PINP and ALP levels were evidently higher when compared to kit references for adults. Reference ranges for calcium, phosphate and PTH also differed from those provided by kit manuals. Serum ALP, PINP, phosphate and PTH changed with age (all P < 0.005), and were significantly higher in boys than in girls (all P < 0.05). Serum 25(OH)D and TSH levels didn't correlate with PINP, ALP and β-CrossLaps (all P > 0.05). In conclusion, unique reference ranges should be provided for adolescents. BMI, sex and age independently influence certain serum bone markers in adolescents. Vitamin D deficiency is widespread. Serum levels of vitamin D and TSH may not influence bone turnover markers in this population.