SummaryPremature infants are a major risk group for bone metabolic disorders. The purpose of this study is to clarify certain aspects of bone metabolism in healthy preterm and fullterm neonates. Forty neonates (20 preterm and 20 fullterm) were the material of the study. For each neonate demographic data (gender, gestational week) and anthropometric data (body weight) were recorded. Blood samples were collected and biochemical markers of bone metabolism (serum ALP, Ca, P, Mg) were immediately estimated. According to the results there is a statistically significant difference in average ALP of preterm neonates compared to full term neonates. Slightly higher values of Ca, P, Mg occurred in premature neonates while there was a statistically significant difference in the weeks of gestation and body weights between the two groups. It is typical in premature neonates the decrease in levels of ALP by the weeks of gestation and the stable levels of Ca. Gestational week seems to positively affect P and Mg levels in preterm neonates. Conclusively from our study's results arises that the week of gestation and not so much the body weight influence the alterations of bone biochemical biomarkers in healthy premature newborns. It seems that very premature neonates have high levels of serum ALP in decompensation of lower levels of Mg and P from all the newborns in this study. Therefore in very premature neonates, it is recommended to estimate serum ALP, Mg and P for assessment of bone turnover.

Background Almost 30% of the premature infants have low body weight and bone mineral density due to prematurity. There is no consensus of screening premature neonates for metabolic bone disease; therefore, it is important to investigate the use of bone biochemical parameters. Latest studies involved the activity of acetylcholinesterase as a mediator in bone remodeling. It is hypothesized that there is a possible correlation of bone biochemical biomarkers and acetylcholinesterase (AChE) activity in premature infants. Methods We studied 50 neonates (26 preterm with gestational age <32 weeks, 24 full-term). Clinical data (sex, gestational week) and anthropometric parameters (body weight) were recorded. We directly measured the bone biochemical markers in serum such as alkaline phosphatase (ALP), calcium (Ca), phosphorus (P), magnesium (Mg) and parathyroid hormone (PTH). In addition, we measured the AChE activity. Results ALP and parathyroid hormone levels were higher, but Ca, P and AChE were lower in premature neonates group compared with full-term ones. There is a significant positive correlation of gestational age with body weight, Ca and AChE. A significant negative correlation was observed for ALP and PTH with gestational age. Conclusions We found a gestational age-related increase of AChE activity. There were significant relationships between AChE activity with P and PTH.