1. Netherlands Institute for Pigment Disorders/Department of Dermatology; Academic Medical Centre; Meibergdreef 9 1105 AZ Amsterdam the Netherlands
2. Department of Dermatology; EMGO Institute for Health and Care Research; VU Medical Centre; Amsterdam the Netherlands
3. Department of Epidemiology and Biostatistics; EMGO Institute for Health and Care Research; VU Medical Centre; Amsterdam the Netherlands
4. Department of Dermatology; MC Haaglanden; Den Haag the Netherlands