Epidermal Thickness at Different Body Sites: Relationship to Age, Gender, Pigmentation, Blood Content, Skin Type and Smoking Habits

TLDR

The study examined how epidermal thickness varies with age, gender, skin type, pigmentation, blood content, smoking habits, and body site. The authors measured stratum corneum and cellular epidermis thickness from biopsies of three body sites in 71 volunteers and used multiple regression to assess the independent effects of these factors. Epidermal thickness differed by body site, with the dorsal forearm having the thinnest stratum corneum and the buttock the thickest cellular epidermis; stratum corneum thickness correlated positively with pigmentation and negatively with smoking duration, while cellular epidermis thickness correlated positively with blood content and was greater in males, with no association to age or skin type.

Abstract

Epidermal thickness and its relationship to age, gender, skin type, pigmentation, blood content, smoking habits and body site is important in dermatologic research and was investigated in this study. Biopsies from three different body sites of 71 human volunteers were obtained, and thickness of the stratum corneum and cellular epidermis was measured microscopically using a preparation technique preventing tissue damage. Multiple regressions analysis was used to evaluate the effect of the various factors independently of each other. Mean (SD) thickness of the stratum corneum was 18.3 (4.9) microm at the dorsal aspect of the forearm, 11.0 (2.2) microm at the shoulder and 14.9 (3.4) microm at the buttock. Corresponding values for the cellular epidermis were 56.6 (11.5) microm, 70.3 (13.6) microm and 81.5 (15.7) microm, respectively. Body site largely explains the variation in epidermal thickness, but also a significant individual variation was observed. Thickness of the stratum corneum correlated positively to pigmentation (p = 0.0008) and negatively to the number of years of smoking (p < 0.0001). Thickness of the cellular epidermis correlated positively to blood content (P = 0.028) and was greater in males than in females (P < 0.0001). Epidermal thickness was not correlated to age or skin type.