1. Children’s Clinical University Hospital, Vienibas Gatve 45, LV-1004 Riga, Latvia
2. Department of Paediatrics, Riga Stradins University, Vienības Gatve 45, LV-1007 Riga, Latvia
3. Department of Public Health and Epidemiology, Institute of Public Health, Riga Stradins University, Kronvalda Boulevard 9, LV-1010 Riga, Latvia
4. Institute of Occupational Safety and Environmental Health, Riga Stradins University, Dzirciema 16, LV-1007 Riga, Latvia