UCLA Center for Health Policy Research, University of California, Berkeley - Division of Environmental Health Sciences, University of California, Berkeley - Division of Environmental Health Sciences, University of California, Los Angeles (UCLA) - Department of Neurology, University of California, Berkeley - Division of Environmental Health Sciences, University of California, Los Angeles (UCLA) - Department of Epidemiology, University of California, San Francisco (UCSF) - Department of Epidemiology and Biostatistics and University of California, Los Angeles (UCLA) - Department of Environmental Health Sciences