[1] Univ Jyvaskyla, Dept Biol & Environm Sci, SF-40351 Jyvaskyla, Finland
[2] Finnish Inst Occupat Hlth, Helsinki, Finland
[3] Univ Helsinki, Inst Biotechnol, FIN-00014 Helsinki, Finland
[4] Tampere Univ Hosp, Dept Dermatol, Tampere, Finland
[5] Natl Publ Hlth Inst, Helsinki, Finland