Clinical vs. chronological skin age: exploring determinants and stratum corneum protein markers of differential skin ageing in 351 healthy women

Apparent skin age can be determined by several clinical measurements and may differ from chronological age, hence defining age acceleration/deceleration (Age A/D). Using data from 360 women with dermatological scoring of 21 clinical signs, we defined 3 well-separated co-occurring classes capturing the dryness, the elasticity and the oily nature of the skin. We related the risk of each clinical signs to the stratum corneum levels of 5 pre-selected proteins, we identified specific chronological age-adjusted signatures of each clinical sign. Using variable selection approaches, we identified 6 (of the 21) clinical signs which were jointly predictive of chronological age and used to define the clinical skin age, and subsequently age A/D. Applying univariate and multivariate approaches we found that stratum corneum levels of insulin degrading enzyme (IDE) was protective against (β = - 1.74, p = 3.3 × 10^-6; selection proportion > 90%) accelerated skin ageing. In conclusion, our results support the fact that molecular markers found in the stratum corneum could predict skin ageing acceleration/deceleration.