Background Phototherapy is used on the majority of preterm infants with unconjugated hyperbilirubinaemia. The use of fluorescent tube phototherapy is known to induce oxidative DNA damage in infants and has largely been replaced by blue light-emitting diode phototherapy (BLP). To date, it is unknown whether BLP also induces oxidative DNA damage in preterm infants.
Objective To determine whether BLP in preterm infants induces oxidative DNA damage as indicated by 8-hydroxy-2′deoxyguanosine (8-OHdG).
Design Observational cohort study.
Methods Urine samples (n=481) were collected in a cohort of 40 preterm infants (24–32 weeks’ gestational age) during the first week after birth. Urine was analysed for the oxidative marker of DNA damage 8-OHdG and for creatinine, and the 8-OHdG/creatinine ratio was calculated. Durations of phototherapy and levels of irradiance were monitored as well as total serum bilirubin concentrations.
Results BLP did not alter urinary 8-OHdG/creatinine ratios (B=0.2, 95% CI −6.2 to 6.6) at either low (10–30 µW/cm2/nm) or high (>30 µW/cm2/nm) irradiance: (B=2.3, 95% CI −5.7 to 10.2 and B=−3.0, 95% CI −11.7 to 5.6, respectively). Also, the 8-OHdG/creatinine ratios were independent on phototherapy duration (B=−0.1, 95% CI −0.3 to 0.1).
Conclusions BLP at irradiances up to 35 µW/cm2/nm given to preterm infants ≤32 weeks’ gestation does not affect 8-OHdG, an oxidative marker of DNA damage.
- oxidative stress
- neonatal hyperbilirubinaemia
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Contributors LWEvdS: designed the set-up of the study, coordinated the study and performed 8-hydroxy-2’deoxyguanosine (8-OHdG) sample analyses, data management and statistical analyses. She wrote the majority of the manuscript. MHJRvF: assisted in 8-OHdG sample analyses and designed, validated and optimised the respective method. IK: created the idea for the 8-OHdG analyses and supervised the development of this technique. DHB and AJO: supervised the sample collection by the NICU nurses and performed phototherapy intensity measurements. JWJ: was responsible for daily supervision of all laboratory work, analyses and project planning. HJV: responsible for supervision of the project and regular critical evaluations of study design, study course and manuscript. HG: provided statistical advice during set-up of the study, statistical analyses and drafting of the manuscript and reviewed the manuscript to assure statistical correctness. CVH: created the idea for the study, performed daily supervision of clinical activities, data management, statistical analyses and writing of the manuscript. All authors contributed to the writing of the manuscript.
Funding This study was funded by the Dr. C.J. Vaillant foundation and 'Stichting Vrienden Beatrix Kinderziekenhuis'.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the Medical Ethics Committee of the UMCG (METC 2016/437).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.