1. Department of Neurology; Wake Forest School of Medicine, Main Floor Reynolds Tower; Winston-Salem North Carolina 27157 USA
2. Center for Worker Health; Wake Forest School of Medicine; Winston-Salem North Carolina USA
3. Department of Biostatistical Sciences, Division of Public Health Sciences; Wake Forest School of Medicine; Winston-Salem North Carolina USA
4. Department of Family and Community Medicine; Wake Forest School of Medicine; Winston-Salem North Carolina USA
5. Department of Epidemiology and Prevention, Division of Public Health Sciences; Wake Forest School of Medicine; Winston-Salem North Carolina USA