title: The skin aging index: a new approach for documenting anti-aging products or procedures.
abstract: OBJECTIVE
  The overall appearance of an aged skin is characterized by a combination of several attributes such as wrinkles, brown spots and sagging. Our objective was to develop and validate a statistical framework to assess the overall anti-ageing benefits of products/procedures.
  
  
  METHODS
  Different skin attributes were evaluated by a clinical grader and combined using a Principal Component Analysis (PCA). The Skin Ageing Index was defined as the normalized projection of the clinical grading values on the first PCA axis. Several Skin Indexes were built by grouping specific parameters related to a skin condition such as overall ageing, wrinkles and sagging. The method was validated following two steps. Firstly, a clinical study was performed on 173 Caucasian women and the correlation between the Skin Indexes and the volunteers' real and perceived age was estimated. Secondly, a double-blinded placebo-controlled randomized study was performed on 87 Caucasian women to assess the efficacy of an anti-wrinkle cream containing retinol, hyaluronic acid and dihydroxymethylchromone. Facial wrinkles were clinically evaluated and a Wrinkle Index was built.
  
  
  RESULTS
  All indexes were highly correlated with the real and the perceived age (0.57 ≤ Pearson R ≤ 0.92, P-value ≤ 0.05). Finally, the Wrinkle Index provides documented evidence that the tested product significantly reduced the appearance of wrinkles versus the placebo and the baseline assessment (-23.53% after 4 weeks, -27.83% after 8 weeks).
  
  
  CONCLUSIONS
  Skin ageing Indexes capture information relevant to the visual transformation of facial skin with age, while providing documented product benefits. These tools may enable a simpler and more consistent comparison of anti-ageing products/procedures.
authors.affiliation: Johnson & Johnson Santé Beauté France, 92787 Issy-les-Moulineaux, France. ankengne@its.jnj.com
authors.forename: Alex
authors.initials: A
authors.lastname: Nkengne
authors.forename: Romain
authors.initials: R
authors.lastname: Roure
authors.forename: Ana Beatriz
authors.initials: AB
authors.lastname: Rossi
authors.forename: Christiane
authors.initials: C
authors.lastname: Bertin
mesh_terms: D000328:Adult; D000368:Aged; D003358:Cosmetics / Q000008:administration & dosage*; D003879:Dermatologic Agents / Q000008:administration & dosage*; D004282:Documentation / Q000379:methods / Q000706:statistics & numerical data*; D004311:Double-Blind Method; D005260:Female; D005602:France / Q000453:epidemiology; D006305:Health Status Indicators; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015595:Skin Aging / Q000187:drug effects* / Q000502:physiology*; D016896:Treatment Outcome; D064232:Visual Analog Scale; D055815:Young Adult
chemical_list: D003358:Cosmetics; D003879:Dermatologic Agents
keywords: PCA; aging; aging index; clinical evaluation; products comparison