1. Epidemiology and Public Health Sciences, Department
of Public Health and Clinical Medicine, UmeÅ University, UmeÅ,
Sweden, urban.janlert@epiph.umu.se
2. Epidemiology and Public Health Sciences, Department
of Public Health and Clinical Medicine, UmeÅ University, UmeÅ,
Sweden, Department of Community Health, Norrbotten County Council,
LuleÅ, Sweden