From the *Back Research Center, Ringe, Denmark; ‡Danish Twin Registry, University of Southern Denmark, Odense, Denmark; §Department of Statistics and Demography, University of Southern Denmark, Odense, Denmark; ¶Department of Neurology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Occupational Medicine, Odense University Hospital, Odense, Denmark; and #Department of Rheumatology, Odense University Hospital, Odense, Denmark.
Acknowledgment date: February 5, 2003. First revision date: July 10, 2003. Acceptance date: July 21, 2003.
L.H. was supported by the Foundation for Chiropractic Research and Postgraduate Education, Denmark.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Foundation funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence to Lise Hestbaek, DC, Back Research Centre, Hospital of Funen, DK-5750 Ringe, Denmark; E-mail: [email protected]