Correction: “Reduction in BMI z-score and improvement in cardiometabolic risk factors in obese children and adolescents. The Oslo adiposity intervention study - a hospital/public health nurse combined treatment.”

Correction After publication of this work [1], it came to our attention that the laboratory we use changed the method of analysis for insulin and C-peptide during our data collection. Before March 2007 the method used for insulin was competitive radioimmunoassay (Linco Research Inc, St Charles, MO, USA) and for C-peptide competitive luminoimmunoassay (Immulite 2000, Diagnostic Products Corporation, CA, USA). After March 2007 noncompetitive immunofluorometric assays (DELFIA kit form Wallac OY, Turku, Finland) were used. We have therefore recalculated the insulin and Cpeptide values analyzed after March 2007, and repeated the statistical analyses involving insulin, C-peptide and HOMA-IR.