ABSTRACT

Parallel to improvements in Neonatal Units Care quality, survival of very low birth weight infants improves leading to increase in frequencies of other health problems and osteopenia of prematurity.

In our study, 20 premature infants of less than 34 weeks’ gestation followed in Ankara Training and Research Hospital Neonatal Unit and 20 healthy mature infants were included. Serum calcium, phosphorus, magnesium levels, alkalen phosphatase activity, plasma 25- hydroxy vitamin D levels were evaluated within the first week after birth and at the end of 40th week in premature infants and within the first week after birth in mature infants. Right middle tibia’s bone speed of sound value was measured by quantitative ultrasonography. Evaluation of comparing bone SOS values with infants’ biochemical parameters, whether premature infants take enough Ca, P, D vitamin supplementation and if medication taken is effective on bone SOS values was aimed.

Serum phosphorus, magnesium, 25-hydroxy vitamin D levels, bone speed of sound values measured within the first week after birth and at the end of 40th week in premature infants were similar, serum calcium and alkalen phosphatase levels in premature infants were significantly lower within the first week than at the end of 40th week [8-9.6 mg/dl; 166.6-293 U/L, respectively, p=0.001]. Serum calcium, phosphorus levels at the end of 40th week in premature infants and in healthy mature infants were similar. Serum alkalen phosphatase activities, magnesium levels and plasma 25-hydroxy vitamin D levels at the end of 40th week in premature infants were higher than in mature infants [293±71-178±57 U/L, 0.9-0.8 mmol/L and 38±14-27.3±12 nmol/L, respectively; p 0.001]. In premature infants bone speed of sound values measured at the end of third and sixth months were higher than measure within first week (2928.1 m/sec, 3007.9 m/sec, 2851 m/sec, respectively; p=0.001). Measured bone SOS values at the end of 40th week in premature infants were lower than in healthy mature infants (respectively 2851 m/sec and 3093 m/sec; p=0.01). There was no significant difference in bone SOS values between premature infants taking human milk fortifier or not, having intravenous calcium medication or not and receiving phototherapy or not (p>0.05).

Using quantitative USG in evaluation of premature osteopenia was an easy, cheap and non-invasive method. It was found that bone SOS values measured at the end of 40th week in premature infants were lower than in mature infants. Also it was determined that human milk fortifiers weren’t very effective on bone SOS values. But we thought that this can be caused by small size of our study group.

Keywords: Premature osteopenia, quantitative USG, 25 (OH) vitamin D