Comparative study of rheological and surface pattern parameters of human skin as a function of age, work conditions...

The present study deals with the comparison of three non-invasively measurable parameters of human skin as a function of age and environmental factors. Two of them are related to mechanical properties and one to the surface microtopography of the skin. Three populations were studied living in different conditions concerning exposure of skin to external influences. The first population (cloistered nuns) lives in well controlled, uniform conditions (skin is always hidden from solar radiation), the second one is regularly exposed to infrared radiation (glass-blowers) and the third one represents an average population (white-collar workers). Two of the studied parameters seem interesting for the estimation of biological aging which may not be identical to chronological age. The first one, the elastic rebound of the skin, is generally well correlated to age but the rate of change is rather slow. The other one, related to the skin surface relief, also generally well related to age, changes faster but the dispersion of the individual results is greater than for elastic rebound. For a better estimation of biological aging the determination of both parameters seems to be preferable to the determination of any of them individually.