1. Environmental Epidemiology Division, Israel Ministry of Health, Jerusalem 9446724, Israel
2. Negev Environmental Health Research Institute, Soroka University Medical Center, Beer-Sheva P.O. Box 651, Israel
3. Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva P.O. Box 653, Israel
4. Neurology Department, Soroka University Medical Center, Beer-Sheva P.O. Box 651, Israel
5. Department of Geography and Environmental Development, Faculty of Humanities and Social Sciences, Ben-Gurion University of the Negev, Beer-Sheva P.O. Box 653, Israel
6. Soroka Clinical Research Center, Soroka University Medical Center, Beer-Sheva P.O. Box 651, Israel