1 University of Calgary, Department of Medicine, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
2 Department of Internal Medicine 3, University of Erlangen-Nuremberg, Erlangen 91054, Germany.
3 Institute for Biomechanics, ETH Zurich, Wolfgang-Pauli-Strasse 14, 8093 Zurich, Switzerland.
4 Department of Internal Medicine, Subdivision of Rheumatology, CAPHRI/NUTRIM, Maastricht University Medical Centre, P. Debyelaan 25, Postbus 5800, 6202 AZ, Maastricht, Netherlands.