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

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.

Effect of Age, Gender, and Sun Exposure on Ethnic Skin Photoaging: Evidence Gathered Using a New Photonumeric Scale

BACKGROUND

African-Americans are less affected by photoaging than lighter skin individuals. Although scales for photoaging have been developed for Caucasians and Asians, no scale exists for African-Americans.

AIM

To develop a photonumeric scale for photoaging and to determine factors that contribute to photoaging in African-Americans.

METHODS

Five participants' photographs were selected as standards to create a 9-point photonumeric scale (0 = none, 8 = most severe). Three blinded dermatologists used the scale to grade the remaining participants' photographs.

RESULTS

Interrater reliabilities were 0.775 (95% CI: 0.635, 0.880) for trial 1 and 0.832 (0.747, 0.883) for trial 2. Intrarater reliabilities, assessed over a 1 week interval, were 0.863 (0.727, 0.940), 0.928 (0.890, 0.954), and 0.866 (0.739, 0.935) for the three graders, indicating strong agreement. Photoaging scores were then correlated with participants' survey on lifestyle factors, which yielded age as a significant predictor (r = 0.91, p < 0.001). Furthermore, multiple regression model to predict facial photoaging (adjusted R² = 0.849) selected age (b₁ = 0.111, p < 0.001), sun exposure (b₂ = 0.206, p = 0.014), and gender (b₂ = -0.388, p = 0.063) as the most important variables.

CONCLUSIONS

A reliable photonumeric scale for photoaging in African Americans was developed. Age, sun exposure, and male gender were found to be contributory factors to photoaging.