Plasma metabolome and circulating vitamins stratified onset age of an initial islet autoantibody and progression to type 1 diabetes: the TEDDY study

Children’s plasma metabolome, especially lipidome reflects gene regulation and dietary exposures, heralding the development of islet autoantibodies (IA) and type 1 diabetes (T1D). The TEDDY study enrolled 8676 newborns by screening HLA-DR-DQ genotypes at six clinical centers in four countries; profiled metabolome and measured concentrations of ascorbic acid, 25-hydroxyvitamin D (25(OH)D), erythrocyte membrane fatty acids following birth until IA seroconversion under nested case-control design. We grouped children having an initial autoantibody only against insulin (IAA-first) or glutamic acid decarboxylase (GADA-first) by unsupervised clustering of temporal lipidome, identifying a subgroup of children having early onset of each initial autoantibody, i.e., IAA-first by 12 months and GADA-first by 21 months, consistent with population-wide early seroconversion age. Differential analysis showed that infants having reduced plasma ascorbic acid and cholesterol experienced IAA-first earlier, while early onset of GADA-first was preceded by reduced sphingomyelins at infancy. Plasma 25(OH)D prior to either autoantibody was lower in T1D progressors compared to non-progressors, with simultaneous lower diglycerides, lysophosphatidylcholines, triglycerides, alanine before GADA-first. Plasma ascorbic acid and 25(OH)D at infancy were lower in HLA-DR3/DR4 children among IA cases but not in matched controls, implying gene expression dysregulation of circulating vitamins as latent signals for IA or T1D progression.