This cross-sectional study was conducted in NICU of a government tertiary-care hospital from April 2015 to April 2016 after approval by institutional ethics committee.

Convenience sample of 82 preterm neonates with indirect hyperbilirubinemia requiring phototherapy in the first week of life were included after obtaining consent from parents. Neonates with hemolytic jaundice, with jaundice within 24 hours of life, requiring ventilation, and with birth asphyxia were excluded. Total oxidant status (TOS), total antioxidant capacity (TAC) and Oxidative stress index (OSI) were estimated to assess the effect of phototherapy on oxidant-antioxidant status of neonates.

Venous sampling was done prior to and at 48 hours after phototherapy to determine total bilirubin, TOS and TAC. TOS and TAC were measured by Erel’s method with an autolyser using a kit (Rel Assay Diagnostics, Mega Tip Company, Gaziantep, Turkey) [7,8]. OSI was calculated as TOS/TAC /100 [3,4]. Relevant baseline demographic, clinical and biochemical parameters were recorded in all subjects.

Data were analyzed using SSPS version 16. The OSI before and after phototherapy within the same group were compared using Wilcoxon signed rank test. The change between the pre- and post-phototherapy values were calculated for TOS, OSI and TAC. ÄTOS and ÄTAC were compared across groups using Mann-Whitney test.

Forty-one preterm neonates each received LED and conventional phototherapy. The mean (SD) gestational age was 32.9 (1.9) weeks and mean (SD) birth weight 1.6 (0.33) kg. Table I depicts baseline characteristics of the two groups. There were no statistically significant differences except for gestational ages ( P <0.001).

TABLE I Baseline Characteristics of the Study Groups

Post-phototherapy, mean (SD) OSI increased significantly compared to baseline in both conventional [0.26 (0.24) vs 0.61 (0.41); P <0.001] and LED groups [0.24 (0.20) vs 0.32 (0.23); P <0.001]. Table II compares the post phototherapy parameters indicating that conventional phototherapy resulted in higher oxidative stress.

TABLE II	Comparison of Oxidant and Antioxidant Parameters After Conventional and LED Phototherapy 

Binary logistic regression analysis showed that conventional phototherapy [odds ratio (95% CI) 30.8 (5.0-188.9)] and sepsis positivity [odds ratio (95% CI) 12.1 (2.5-51.2)] were significant in predicting higher oxidative stress index when controlled for gestational age, birthweight, surfactant administration and oxygen administration.

The present study, done exclusively among preterm neonates, compared antioxidant-oxidant parameters following conventional and LED phototherapy. Both conventional and LED phototherapy resulted in increased oxidative stress index. However, derangement of antioxidant-oxidant parameters was more pronounced after conventional as compared to LED phototherapy.

The study had a convenience sample and randomization would have increased the strength of evidence. The two groups compared had statistically significant difference in the gestational ages. However, since baseline TAC, TOS and OSI levels were comparable, the difference in gestational ages alone is unlikely to have affected the results.

The baseline TAC in the present study were lower than values reported by Demirel, et al. [4]. The lower TAC could be due to lower gestational age of neonates in the present study. The finding supports the evidence that preterm neonates have immature antioxidant system [9]. Our observation of increase in OSI after both conventional and LED phototherapy is in agreement with the study done by Kale, et al. [5]. However, another study reported increased oxidative stress following conventional but found no significant change following LED phototherapy [4]. The differences observed could be due to dissimilarities in characteristics of the study population, phototherapy equipment, used and timing of sample collection.

We conclude that both conventional and LED phototherapy altered the antioxidant oxidant status towards the oxidant side with the effect of the former being more pronounced than the latter. In light of the findings, we recommend judicious use of phototherapy among preterm neonates who have a lower baseline antioxidant capacity.

Contribution: AA: conceived and designed the study, prepared the protocol, collected data, drafted the manuscript; SRR: designed the study, supervised data collection, analyzed and interpreted the data, revised the manuscript for important intellectual content; BSB: conceived the study, co-ordinated in data collection, provided critical inputs to the manuscript writing; KB: designed the study, critically reviewed the manuscript; NJ: designed the study, guided in analyzing the data. All authors approved the final version of manuscript.

Funding: None; Competing interest: None stated.