Why skin color matters for infant jaundice

Jaundice is one of the most common medical issues in newborns, affecting nearly 80% of full-term infants in their first days of life. The condition occurs when excess bilirubin, a yellow pigment formed as red blood cells break down, builds up in the body. While mildcases usually resolve on their own, dangerously high bilirubin levels can cause brain damage or even death. The standard treatment, phototherapy, uses blue light to break bilirubin down into forms the body can excrete.

A theoretical study recently published in Biophotonics Discovery used computer modeling to examine how skin color and other skin properties might influence how much therapeutic light reaches target tissues.

Researchers from the University of Twente, Isala Hospital, and University Medical Center Groningen employed advanced computer simulations to model light penetration in newborn skin. The simulations incorporated factors such as skin pigmentation, hemoglobin levels, bilirubin concentration, skin thickness, and treatment light wavelength.

Since specific data on skin color variations in newborns have not yet been reported, the researchers based their pigmentation parameters on established measurements from adult skin data. The modeling predicted that skin pigmentation would have the largest effect on light penetration.

Compared with light-skinned infants, the simulations suggested dark-skinned infants might receive up to 5.7 times less effective light dose under identical settings. This theoretical difference translated into predicted bilirubin reductions of about 40.8% for light-skinned newborns after 24 hours of phototherapy, versus 25.6% for dark-skinned newborns. The model also predicted that epidermal thickness and bilirubin levels would influence treatment effectiveness, though to a lesser degree.

The simulations further suggested that optimal treatment wavelength might vary by skin color. While light-skinned infants were predicted to respond best at around 460 nanometers (nm), dark-skinned infants showed better theoretical responses at slightly longer wavelengths, around 470 nm. The researchers propose that a compromise wavelength near 465 nm could provide more consistent results across skin tones.

Current phototherapy guidelines use a standardized approach without adjustments for skin tone. While phototherapy generally demonstrates effectiveness across populations, the authors note their theoretical findings suggest it might be less efficient in darker-skinned infants, potentially affecting treatment duration and outcomes.

Highlighting the importance of obtaining more fundamental insight into newborn skin pigmentation, they also emphasize the critical need for clinical studies to validate these computational predictions and determine whether actual bilirubin reduction varies by skin color in real patients.

“Our modeling suggests skin color significantly influences the amount of light absorbed by bilirubin during treatment,” concludes corresponding author Alida J. Dam-Vervloet. “However, these are theoretical predictions that need clinical validation. Real-world studies measuring actual bilirubin reduction across different skin tones are essential to determine whether more personalized phototherapy approaches are warranted in real newborn infants receiving phototherapy.”