1. Senior Research Associate, Department of Epidemiology and Global Health, Umeå University, SE-901 87 Umeå, Sweden.
2. Professor, Department of Epidemiology and Global Health, Umeå University, SE-901 87 Umeå, Sweden
3. Associate Professor, Department of Epidemiology and Global Health, Umeå University, Umeå SE-901 87, Sweden