Chronological Aging in African-American Skin: A Reliable Photonumeric Scale Demonstrates Age and Body Mass Index as Contributing Factors

Abstract

Background: Increased photoprotection by natural melanin allows for African-Americans to be less impacted by photoaging than Caucasians. However, less is known about chronological aging in this population.

Objective: To create a photonumeric scale for African-Americans to evaluate chronological skin aging and to explore contributing elements to intrinsic aging.

Methods: Standardized photographs of the upper inner arm were taken from 75 African-American participants. Five participants were chosen as standards to create a 9-point photonumeric scale (0 = none, 8 = most severe). The scale was utilized by three blinded dermatologists to independently rate participants' photographs.

Results: The interrater agreements were 0.768 (95% CI: 0.671-0.834) for trial 1 and 0.725 (0.608-0.794) for trial 2. The intrarater agreements were 0.757 (0.596-0.875), 0.850 (0.771-0.903), and 0.790 (0.686-0.855) for the three raters. Averaged chronological aging scores were correlated with participants' survey responses, which revealed age as a significant predictor (r = 0.72, p < 0.001).

Limitation: Our study was limited by the sample size, although the number of study participants was similar on a investigation in Caucasians.

Conclusion: This study created the first reliable photonumeric scale for chronologic skin aging in African-Americans and found increased age and greater BMI as contributors to intrinsic skin aging phenotype in this population.

Keywords: African Americans; Aging; Caucasians; Ethnic skin; Sun-exposed skin; Sun-protected skin.