1. Environmental and Occupational Medicine, Department of Medical Sciences, Uppsala University, 751 05 Uppsala, Sweden
2. Department of Neurobiology, Care Sciences and Society, Primary Care Medicine, Karolinska Institute, 171 77 Stockholm, Sweden
3. Department of Medical Sciences, Section of Infectious Diseases, Uppsala University, 751 05 Uppsala, Sweden
4. Department of Health Economics and Management, School of Public Health, Urmia University of Medical Sciences, Urmia 57147-83734, Iran