1. Centre for Epidemiology, National Board of Health and
Welfare, SE-106 30 Stockholm Sweden, gudrun.persson@sos.se
2. Centre for Epidemiology, National Board of Health and
Welfare, SE-106 30 Stockholm Sweden
3. Department of Public Health Sciences, Karolinska Institute,
Stockholm, Sweden, finn.diderichsen@socmed.ki.se
4. National Institute ofHealth, SE-103 52 Stockholm, Sweden,
bosse.pettersson@fhi.se
5. Department of Public Health & Clinical Medicine, Umeå university, SE-90 185 Umeå, Sweden, stig.wall@epiph.umu.se