Correlation Between Early Changes In Biochemical Markers Of Bone Metabolism And Early Nutrition Of Preterm Infants

Objective By detecting β-CTX、OC、PINP of the biochemical markers of bonemetabolism in serum within the24hours life and at the time of2weekslife,recording nutritional intake during hospitalization,to determine the early changesof the biochemical markers of bone metabolism and its correlation with the earlynutrition in preterm infants.Methods Between November1,2012~April30,2013we studied60pretermnewborns, who were admited to The first people’s hospital of Chenzhou affiliatedUniversity of south China,the gestational age of those infants were between30weeksto35weeks. All objects are drawn blood2ml respectively, within24hours after birthand after birth, from8:00to9:00in the morning, determine the Serum β-CTX, OC,PINP levels by using electrochemiluminescence. Daily caloric （kcal/kg.d), dailycalorie milk（kcal/kg.d), daily protein（g/kg.d), daily P/E (g/100kcal), cumulative lossof protein(g/kg）,caloric cumulative loss(kcal/kg) were recorded and calculated.Correlation among the serum β-CTX, OC, PINP levels within24hours after birth,changes in the difference of β-CTX,OC,PINP level within2weeks after birth, andcorrelation between the β-CTX,OC,PINP markers and gestational age within2weeksafter birth, were statistical analyzed by using bivariate correlation analysis. Thechanges of serum β-CTX, OC, PINP level2weeks and24hours after birth wereanalyzed by t test; correlation between serum β-CTX, OC, PINP change differenceand nutritional factors within2weeks after birth was analyzed by curve fitting.Results1Correlation among the serum β-CTX, OC, PINP levels within24hours afterbirth:β-CTX and OC no correlation （r=0.002, P>0.05）, β-CTX and PINP no correlation（r=0.031，P>0.05），OC and PINP no correlation（r=0.170，P>0.05）.2Serum β-CTX levels negatively correlated with gestational age within24hours after birth（r=-0.603, P <0.05）， serum OC level was positively correlatedwith gestational age（r=0.581, P <0.05），serum PINP level was positively correlatedwith gestational age（r=0.134,P>0.05）.3Serum β-CTX, OC, PINP levels significantly increased within2weeks afterbirth compared with24hours after birth, the difference is statistically significant.4Δβ-CTX and ΔOC is a positive relationship（r=0.600,P <0.05）；Δβ-CTX andΔPINP was no correlation（r=0.045，P>0.05）；ΔOC andΔPINP was no correlation（r=0.110，P>0.05）.5There is correlation betweenΔOC and daily caloric （R=0.645,P <0.05）,betweenΔOC and daily P/E（R=0.562,P <0.05）, betweenΔOC and the cumulativeloss of calories（R=-0.321, P <0.05），and no correlation among ΔOC and the milkdaily calories, the average daily amount of protein, the amount of protein accumulatedlosses（P>0.05）； there is no correlation among Δβ-CTX、ΔPINP and daily calories,daily calorie milk, the average daily amount of protein, daily average P/E, thecumulative loss of protein, calories cumulative loss amount（P>0.05）.Conclusions1Bone metabolism at a low bone formation and high bone resorption state,biochemical markers of bone metabolism is closely related to gestational age, OCbone formation index was positively correlated with gestational age, resorption indexβ-CTXwas negatively correlated with gestational age, preterm children born after.2Bone metabolism is active, bone metabolism in serum β-CTX, OC, PINPSignificantly increased,2weeks after birth in preterm children.3Nutrition has an effect on bone metabolism the cumulative loss of calories isclosely related to the changes of serum OC levels, within2weeks after birth inpreterm children;point that it is important for the bone growth and development thatreasonable caloric and suitable P/E are provided early.