Author Contributions: Mr Martin had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Martin, Deyo,
Analysis and interpretation of data: Martin, Deyo, Mirza, Turner, Comstock, Hollingworth, Sullivan.
Drafting of the manuscript: Martin,
Critical revision of the manuscript for important intellectual content: Martin, Deyo, Mirza, Turner, Comstock,
Statistical analysis: Martin, Comstock,
Obtained funding: Deyo, Mirza.
Administrative, technical, or material support: Martin, Mirza.
Study supervision: Deyo, Mirza, Sullivan.
Financial Disclosures: None reported.
Funding/Support: This study was supported in part by grant number P60AR48093 and K23AR48979 from the National Institute of Arthritis, Musculoskeletal, and Skin Diseases (NIAMS).
Mr Martin's research is supported in part by an endowment to the University of Washington's Department of Orthopaedics & Sports Medicine from Surgical Dynamics Inc (more recently purchased by Stryker Corporation).
Dr Deyo's and Dr Mirza's spine research has benefitted from a gift to the University of Washington's Department of Orthopaedics &
Sports Medicine from Synthes Inc, but this study received no support from the Synthes gift.
Role of the Sponsors: The study sponsors had no role in the design or conduct of the study; the collection,
management, analysis, and interpretation of the data; or the preparation,
review, or approval of the manuscript.
Disclaimer: The conclusions and opinions presented herein are those of the authors and not necessarily those of NIAMS, the sponsors, the University of Washington, or Oregon Health & Science University.