Assessment of sun reactive skin type with multiple correspondence analysis, hierarchical and tree-structured classification methods.

The sun reactive skin type classification is based on sunburn susceptibility, tanning ability and phenotypic information. As subjects rarely match all features of a given skin type, the attribution to a class is partially subjective. The aims of the study, were to analyse the contribution of each characteristic to the classification made by the expert, and to establish a classification based on a statistical approach conducted on 212 women living in the Ile-de-France area. Multiple regression was used to construct a formula for each phototype. The coefficients obtained demonstrated that the importance of each characteristic was extremely variable from one phototype to another, suggesting that the phototype determination could be facilitated by adding a weight for every characteristic in the decision. Then, multiple correspondence analysis and clustering analysis methods showed that one phototype could be divided into two more homogenous classes.