Validity of self-reported skin color by using skin color evaluation scale

Although skin color has been suggested to be associated with the risk of some chronic disease, there has been no validated visual skin-color scale, with which subjects can self-report their skin color. Our objective was to develop a visual skin color evaluation scale for self-reporting that would be useful in large-scale epidemiological studies.

Study participants were 99 university Japanese students aged 19-29. We developed a skin color evaluation scale consisting of six colors from light to dark. Participants were asked to choose one color that was the closest to their skin color. Their skin color was measured on the back of the hand and the inner upper arm by an examiner using a narrowband reflective spectrophotometer. Self-reported skin color was compared with the melanin and erythema indices.

Spearman's rank correlation coefficients of self-reported color with the melanin index after adjusted for age, temperature, and humidity were moderate but significant at both sites for both men and women. The correlation coefficients with the erythema index were significant only on the back of the hand for men. The higher melanin index was significantly associated with the darker skin color in both sexes for both sites. The erythema index showed such a significant trend only in men and not in women.

The validity of the skin color chart was moderate of melanin among Japanese people. It may be useful for large population studies examining the relationships between skin color and health outcomes.