Evaluation of Serum Zinc Levels in Hyperbilirubinemic Neonates Before and After Phototherapy.
BACKGROUND
The existing therapeutic methods for neonatal jaundice are costly, time-consuming and potentially risky. Zinc salts can reduce phototherapy duration by precipitating unconjugated bilirubin in the intestine (bilirubin and zinc can form a complex in physiologic pH); however, zinc toxicity is an issue that must be considered since theoretically bilirubin reduction by phototherapy may increase serum zinc levels, making additional zinc supplementation the potential cause of zinc toxicity.


OBJECTIVE
So, our purpose was evaluating the serum zinc level alterations before and after phototherapy, in hyperbilirubinemic newborns.


METHODS
A prospective cohort study was performed at the children's medical center of Tehran University of Medical Sciences from 2012 to 2014. Healthy, full-term exclusively breast fed newborns with non-hemolytic jaundice were enrolled in the study. Participants were divided into two groups based on serum bilirubin levels (TSB < 18 mg/dL and TSB ≥ 18 mg/dL) at admission. Pre- and post-phototherapy total serum zinc level was measured before and 12 - 24 hours after termination of phototherapy.


RESULTS
Phototherapy was associated with a significant increase in the serum zinc level in neonates with severe hyperbilirubinemia (TSB ≥ 18 mg/dL) but not in those with mild-moderate hyperbilirubinemia (TSB < 18 mg/dL). In addition, phototherapy caused a significant increase in the rate of zinc with potentially toxic levels (zinc > 200) in only neonates with severe hyperbilirubinemia.


CONCLUSIONS
Phototherapy increases serum zinc level by reducing bilirubin level so that additional supplementation of this element can lead potentially to zinc toxicity.
Breastfeeding Research Center, Family Health Institute, Tehran University of Medical Sciences, Tehran, IR Iran.
Ziba
Z
Mosayebi
Tehran University of Medical Sciences, Tehran, IR Iran.
Maral
M
Rahmani
Tehran University of Medical Sciences, Tehran, IR Iran.
Shahin
S
Behjati Ardakani
Maternal, Fetal and Neonatal Research Center, Family Health Institute, Tehran University of Medical Sciences, Tehran, IR Iran.
Mahdi
M
Sheikh
Maternal, Fetal and Neonatal Research Center, Family Health Institute, Tehran University of Medical Sciences, Tehran, IR Iran.
Mamak
M
Shariat
Maternal, Fetal and Neonatal Research Center, Family Health Institute, Tehran University of Medical Sciences, Tehran, IR Iran; Maternal, Fetal and Neonatal Research Center, Vali-Asr Hospital, Imam Khomeini Hospital Complex, Tehran, IR Iran.
Golnaz
G
Rezaeizadeh
Hyperbilirubinemia; Neonate; Phototherapy; Zinc