title: Skin from various ethnic origins and aging: an in vivo cross-sectional multimodality imaging study.
abstract: BACKGROUND
  Ethnic differences in skin structural features have not been thoroughly investigated, and the few reported studies are contradictory. Thus, we have carried out a set of in vivo measurements on the skin of about 400 volunteers from various ethnic origins living in the same environment.
  
  
  METHODS
  Female subjects were distributed into four ethnic groups: African Americans, Mexicans, Caucasians, and Chinese. Inter- and intra-ethnic skin structural differences, according to age and anatomic site, were investigated using three non-invasive skin-imaging methods: ultrasound (US) at 25 and 150 MHz, and optical coherence tomography (OCT).
  
  
  RESULTS
  The thickness of the skin is higher on the cheek compared with the dorsal and ventral forearm, with no ethnic or age-related specificity. We confirm that the sub-epidermal non-echogenic band is a sensitive marker of skin aging, and reveal for the first time that it is less pronounced in African Americans. From OCT images, we bring out evidence that the thickness of the dermal-epidermal junction (DEJ) decreased with age, and was higher in African Americans than in Caucasians. Finally, by comparing US images at 150 MHz with OCT images, we show that papillary dermis thickness can be measured and appears to be quite constant irrespective of age or ethnic group.
  
  
  CONCLUSIONS
  Our study confirms that skin imaging is very attractive to further our knowledge of the morphology of skin from various ethnic origins. Regarding age effects, quantitative parameters have shown that they would be delayed in African Americans compared with all other ethnic populations.
authors.affiliation: L'Oréal Recherche, 1, Avenue Eugène Schueller, Aulnay-sous-bois 93601, France. bquerleux@rd.loreal.com
authors.forename: Bernard
authors.initials: B
authors.lastname: Querleux
authors.forename: Thérèse
authors.initials: T
authors.lastname: Baldeweck
authors.forename: Stéphane
authors.initials: S
authors.lastname: Diridollou
authors.forename: Jean
authors.initials: J
authors.lastname: de Rigal
authors.forename: Etienne
authors.initials: E
authors.lastname: Huguet
authors.forename: Frédéric
authors.initials: F
authors.lastname: Leroy
authors.forename: Victoria
authors.initials: V
authors.lastname: Holloway Barbosa
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D017677:Age Distribution; D000368:Aged; D000375:Aging / Q000473:pathology*; D001213:Asian / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D017058:Mexican Americans / Q000706:statistics & numerical data*; D008875:Middle Aged; D012867:Skin / Q000473:pathology*; D014481:United States / Q000208:ethnology; D044465:White People / Q000706:statistics & numerical data*; D055815:Young Adult