In the predefined subgroup analyses, we assessed effect modification of the treatment-2-h-C-peptide AUC (mean change at 24 months) by baseline factors, and the results were generally similar across all pre-selected factors, including age at recruitment, sex, baseline values of BMI, serum 25(OH)D level, HbA1C level, insulin treatment, fasting C-peptide, diabetic ketoacidosis (DKA), as well as HLA subtype (HLA-DR3, -DR4 or -DR9), number of alleles of HLA-DR3, -DR4 or -DR9, and vitamin D receptor (VDR) gene (ApaI, FokI, and BsmI). The gene discussed is VDR; the disease is diabetic ketoacidosis.