1. Cochlear Center for Hearing and Public Health, Johns Hopkins University , Baltimore, Maryland , USA
2. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland , USA
3. Department of Medicine, School of Health and Exercise Sciences, Center for Chronic Disease Prevention and Management, University of British Columbia , Kelowna, British Columbia , Canada
4. Department of Neurology, University of North Carolina School of Medicine , Chapel Hill, North Carolina , USA