[1] GERMAN RHEUMATISM RES CTR, Epidemiol Unit, Berlin, Germany
[2] Univ Munster, Dept Paediat Rheumatol & Immunol, Munster, Germany
[3] Asklepios Clin St Augustin, St Augustin, Germany
[4] German Ctr Paediat & Adolescent Rheumatol, Garmisch Partenkirchen, Germany
[5] Clin City Cologne, Cologne, Germany
[6] Hannover Med Sch, Hannover, Germany