Jerrilyn A Cambron1,2
, M Ram Gudavalli1,3
, Marion McGregor4
, James Jedlicka5
, Michael Keenum6
, Alexander J Ghanayem7,8
, Avinash G Patwardhan7,8
and Sylvia E Furner2 
1
Department of Research, National University of Health Sciences, Lombard IL, USA
2
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, USA
3
Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport IA, USA
4
Independent Consultant, Plano TX, USA
5
Department of Chiropractic Practice, National University of Health Sciences, Lombard IL, USA
6
Orthosport Physical Therapy, Inc., Chicago IL, USA
7
Department of Orthopaedic Surgery and Rehabilitation, Loyola University- Stritch School of Medicine, Maywood IL, USA
8
Edward Hines Jr. Veterans Affairs Hospital, Hines IL, USA