Darker skin types underrepresented in sunscreen trials

Individuals with skin of color are still underrepresented in clinical trials of sunscreens, according to a study.

“Skin of color (SOC) patients have historically been underrepresented in both dermatologic pedagogy and dermatologic research,” Shreya Patel, MD, of the department of dermatology at Boston University’s School of Medicine, and colleagues wrote in a research letter. “Recently, the field of dermatology has made efforts to improve SOC content in educational resources; however, skin type diversity in dermatology research will likely take greater action and time.”

A retrospective review of all clinical and randomized controlled sunscreen trials from 1970 through 2020 was completed with trials being identified by the keywords “sunscreen” and “ultraviolet” on PubMed.

Studies completed in English that included skin type data and ultraviolet protection on human volunteers were included.

Of the 92 trials reviewed, skin type I was included in 43%, whereas skin types II and III were included in 89%, respectively. Skin type IV was included in 34% of trials and skin type V in only 7%. No trials included skin type VI patients.

Clinical photoprotection was the endpoint of 62% of the reviewed trials, while molecular markers were the endpoint for 31% and clinical pigmentation was the endpoint in 7% of trials.

“Most trials studied photoprotection, which relies on erythema, an endpoint easier studied in skin type I to III patients,” the authors wrote. “However, even molecular studies showed overrepresentation of lighter skin type patients.”

Historical exclusion of darker skin types may be due to the difficulty in assessing erythema, however, with a greater understanding of the importance of sun protection in all skin types, representation should increase, according to the authors.

“It is essential that SOC patients are included in relevant sunscreen clinical trials moving forward,” the authors wrote. “While this study specifically examined the lack on inclusivity in sunscreen trials, dermatologic research should work toward greater inclusivity and diversity.”