1 Department of Dermatology, Research Unit of Clinical Medicine, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
2 Infrastructure for Population Studies, Faculty of Medicine, University of Oulu, Oulu, Finland.
3 Department of Dermatology, Research Unit of Clinical Medicine, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland. Electronic address: kaisa.tasanen@oulu.fi.