Correlation analysis between early changes in biochemical markers of bone metabolism and early nutrition of preterm infants / 中国新生儿科杂志

ABSTRACT

Objective To explore the changes of bone metabolic markers during early stage of preterm infants, as well as the relationship with their nutrition status. Methods Preterm infants with gestational age 30-35 weeks admitted to our Hospital were collected from November 2012 to April 2013. Venous blood samples obtained within 24 hours after birth and between 800-900 AM two weeks after birth were used to determine the Serum β-CTx, osteocalcin ( OC) and propeptide of type I procollagen (PINP) levels by Electro-Chemiluminescence. Analysis of changes of these bone metabolic markers and their relationship with early stage nutrition related indicators were also performed. Results A total of 60 premature infants were collected. There was no significant correlation among serum β-CTx, OC and PINP within 24 hours after birth ( r=0. 170, P＞0. 05 ) . The Serum β-CTx within 24 hours after birth was negatively correlated with gestational age (r= -0. 603, P＜0. 05), whereas the serum OC within 24 hours after birth was positively correlated with gestational age ( r=0. 581, P＜0. 05 ) . However, PINP wasn′t correlated with gestational age significantly (r=0. 134,P＞0. 05). Serumβ-CTx, OC and PINP at 2 weeks after birth increased significantly from the baseline level detected within 24 hours after birth ( P＜0. 05 ) .Δβ-CTx was positively correlated with ΔOC (r=0. 600,P＜0. 05). There was no significant correlation between ΔPINP and Δβ-CTx (r=0. 045,P＞0. 05), as well as ΔOC and ΔPINP (r=0. 110,P＞0. 05).ΔOC was positively correlated with average daily calorie ( P＜0. 05 ) and average daily P/E ( P＜0. 05 ) , negatively correlated with cumulative loss of caloric ( P＜0. 05 ) . There was no significant correlation between Δβ-CTx or ΔPINP with nutrition related indicators of this study. Conclusions Serum OC within 24 hours after birth of preterm infants and their gestational age are positively correlated, while β-CTx detected at the same time and gestational age are negatively correlated. Vigorous metabolism of premature bone occurs during the first two weeks after birth, as the serum β-CTx, OC and PINP levels increased significantly. We suggest that reasonable calorie intake and appropriate protein calorie ratio at early stage after birth is very important for the development of bone of preterm infants.