The Effect of Phototherapy Light Intensity on Neonatal Jaundice in Nigeria: Role of Skin

Neonatal jaundice remains one of the most pervasive neonatal conditions worldwide, affecting an estimated 60–80% of term newborns (Olusanya et al.). In sub-Saharan Africa, including Nigeria, the incidence is exacerbated by delays in diagnosis, low access to high-quality phototherapy devices, and systemic healthcare barriers. Phototherapy, the frontline treatment for neonatal jaundice, involves the use of light to transform bilirubin in the skin into water-soluble isomers for excretion. While phototherapy is generally effective, emerging literature and expert consultation suggest that skin pigmentation significantly influences treatment efficacy, a variable often neglected in current standards. This study seeks to tailor phototherapy to the biology of African infants, making life-saving treatment more equitable, faster, and effective.

 

The efficacy of phototherapy depends heavily on the irradiance and wavelength of the light, as well as the proportion of skin exposed. Global guidelines recommend an irradiance of at least 30 μW/cm²/nm (Cline et al.). However, studies show that in many Nigerian hospitals, the average irradiance of phototherapy units is far below this threshold, with over 90% of units delivering less than 10 μW/cm²/nm (Slusher et al.). In darker-skinned neonates, higher melanin concentration in the epidermis further reduces light penetration, especially in the blue spectrum (Setchfield et al.). This poses a double burden: underpowered devices and melanin absorption both contribute to delayed bilirubin breakdown, increasing the risk of complications like kernicterus.

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This study proposes a systematic investigation into how varying phototherapy light intensity influences bilirubin reduction across different skin pigmentation levels in neonates. Specifically, it aims to answer two primary research questions:

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(1) Does increasing phototherapy irradiance accelerate bilirubin decline in dark-skinned neonates compared to lighter-skinned counterparts?

 

(2) Can blue-green wavelength light (~478 nm), which has better tissue penetration, enhance efficacy in melanin-rich skin?

 

It is hypothesized that neonates with darker skin pigmentation will experience a significantly greater bilirubin reduction when treated with higher-intensity or blue-green phototherapy compared to standard treatment.

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To explore these questions, a randomized controlled trial will be conducted in tertiary hospitals across southwestern Nigeria. Eligible neonates diagnosed with hyperbilirubinemia (TSB ≥12 mg/dL) will be categorized into Fitzpatrick skin types III to VI using a standardized colour scale. Within each group, neonates will be randomly assigned to receive either standard phototherapy (~30 μW/cm²/nm, blue light at ~460 nm) or enhanced phototherapy (either 60 μW/cm²/nm blue light or 30 μW/cm²/nm blue-green light at ~478 nm). Bilirubin levels will be measured at baseline and every 6 hours via blood tests. The primary outcome will be the rate of serum bilirubin decline; secondary outcomes include the duration of phototherapy, adverse events, and the need for exchange transfusion. To ensure that the study results are statistically reliable, we estimate that at least 60 neonates will be needed in each treatment group. This number is based on calculations that give us an 80% chance of detecting a real difference in how quickly bilirubin levels drop between the groups, assuming a moderate effect size. Ethical approval for the study will be sought from the appropriate medical research ethics committees in the participating hospitals

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Conducting a multi-site randomized controlled trial in southwestern Nigeria may present logistical challenges such as variability in phototherapy device availability, protocol standardization across hospitals, and the need for staff training on equipment calibration and study procedures. These considerations will be addressed during the study design phase through centralized training and protocol harmonization across the board. Data will be collected on-site by trained research nurses using tablet-based REDCap forms pre-programmed with validation rules to reduce input errors. All entries will sync daily to a centralized, password-protected REDCap server hosted. A dedicated data manager will perform weekly quality checks for inconsistencies, missing fields, and protocol deviations. Cross-site coordination will be supported through biweekly virtual meetings, and any data queries will be resolved in real-time using a shared monitoring dashboard.

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The analysis will utilize two-way ANOVA (Analysis of Variance) to assess the interaction between skin pigmentation and light modality. It is hypothesized that darker-skinned infants will show significantly greater benefit from enhanced phototherapy conditions. Controlling for confounders such as gestational age, feeding status, and baseline bilirubin levels will be essential. Confounding variables such as gestational age, baseline bilirubin level, and feeding status will be recorded from clinical charts and adjusted for in multivariate regression models.

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The significance of this research lies in its potential to inform more equitable treatment protocols. If skin pigmentation is shown to affect phototherapy efficacy significantly, this would warrant revising clinical guidelines to accommodate population-specific needs. Additionally, it could influence the design and regulatory standards of phototherapy equipment for use in African contexts. As global health moves toward precision and inclusivity, acknowledging melanin’s role in treatment outcomes becomes not just relevant but necessary. In addition, the study will remain sensitive to local cultural contexts, including parental consent practices, community trust in medical interventions, and health-seeking behaviours, all of which influence neonatal care in Nigeria.

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Works Cited: 

Cline, Benjamin K., et al. "Phototherapy Device Effectiveness in Nigeria: Irradiance Assessment and Potential for Improvement." Journal of Tropical Pediatrics, vol. 59, no. 4, 2013, pp. 321–325. Oxford University Press, https://doi.org/10.1093/tropej/fmt027.

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Olusanya, Bolajoko O., et al. "The Burden and Management of Neonatal Jaundice in Nigeria: A Scoping Review of the Literature." Nigerian Journal of Clinical Practice, vol. 19, no. 1, 2016, pp. 1–17. https://doi.org/10.4103/1119-3077.173703.

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Setchfield, Keith, et al. "Effect of Skin Color on Optical Properties and the Implications for Medical Optical Technologies: A Review." Journal of Biomedical Optics, vol. 29, no. 1, 2024, 010901. https://doi.org/10.1117/1.JBO.29.1.010901.

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Slusher, Timothy M., et al. "Treatment of Neonatal Jaundice with Filtered Sunlight in Nigerian Neonates: Study Protocol of a Non-Inferiority, Randomized Controlled Trial." Trials, vol. 14, no. 1, 2014, p. 446. https://doi.org/10.1186/1745-6215-14-446.

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