On Wednesday 1 July 2020, M.A. Hamer will defend her PhD dissertation, entitled: ‘Facial Skin Aging: A multidimensional phenotype’.
Skin aging has a large impact on the general population. Besides the cosmetic relevance, it also reflects a person’s health and wellbeing. Facial skin aging is a complex phenotype, which can be evaluated in many different ways. It consists of several different features. In this thesis, four different features were analyzed, namely wrinkles, pigmented spots, telangiectasia, and perceived age. We used mainly continuous digital measures, which we validated first. Digital measures ensure objective and consistent outcomes. We investigated the relationship of these different features with lifestyle- and physiological determinants as well as with genetic variations. We used standardized 3D-photos and data collected from up to 3831 participants of the Rotterdam Study, a large population-based cohort study in Ommoord (a suburb of Rotterdam in the Netherlands) with mainly northwestern European participants aged ≥40 years. We also used other cohort studies (from Leiden, Germany, and the United Kingdom) to verify our initial findings. We confirmed known and identified new determinants for different skin aging features. The varying results of skin color with the different skin aging features show that different skin types age in a different manner: fair-skinned individuals tend to show more atrophic signs of aging (pigmented spots and telangiectasia), whereas darker-skinned individuals show more hypertrophic signs of aging (wrinkles). Results of the genetic analyses were also different per skin aging feature; known skin color genes were associated with pigmented spots and perceived age, but not with wrinkles. This emphasizes the hypothesis that different skin aging features have different (genetic) backgrounds.
The PhD defences will not take place publicly in the Senate Hall or Professor Andries Queridoroom due to the coronavirus. The candidates will defend their thesis online.