From the *Department of Orthopaedics and †Clinical Epidemiology Unit, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; ‡Centre for Clinical Epidemiology and Biostatistics, The University of Newcastle, Newcastle, NSW, Australia; and §Department of Preventive and Social Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Accepted for publication February 4, 2011.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has approved the protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.
Reprints: Patarawan Woratanarat, MD, PhD, Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand (e-mail: [email protected]).
