[1] Division of Epidemiology, B-150 Starlimg-Loving Hall, Ohio State University, Columbus, OH 43210
[2] Dept. of Vet. Preventive Medicine, College of Veterinary Medicine, Ohio State University, Columbus
[3] Division of Epidemiology, School of Public Health, Ohio State University
[4] Department of Veterinary Biosciences, College of Veterinary Medicine, Ohio State University
[5] Department of Veterinary Medicine, Virginia-Maryland Reg. Coll. Vet. M., Univ. of Maryland at College Park, College Park, MD
[6] Disability Prevention Unit, Division of Family Health, State of New York Dept. of Health, Albany