Type 1 diabetes in children - risk factors and prediction

Abstract: Susceptibility genes and environmental factors are important for development of Type 1 diabetes (T1D). Increased birth weight (BW), increased linear growth and gestational infections are among the reported risk factors. T1D is predictable by analysis of HLA genotypes and islet cell autoantibodies. In this thesis risk factors and prediction of T1D were studied as part of the Diabetes Prediction in Skåne (DiPiS) study. In paper I, an analysis of the association between T1D high-risk HLA genotypes, cord blood autoantibodies and BW indicated an increased risk for high relative BW (HrBW) in children with high-risk HLA. Presence of cord blood autoantibodies decreased this risk. In paper II the effect of gestational infections on BW was studied. Infections with fever and/or gastroenteritis during pregnancy increased the risk for HrBW. Furthermore, infections aggravated, but could not fully explain, the association between high-risk HLA and HrBW. The presence of cord blood autoantibodies decreased the risk for HrBW only when occurring together with infections. In paper III, intrauterine and childhood growth, corrected for mid-parental height, in children developing T1D were studied in relation to HLA genotypes. HLA genotypes were associated with SDS of birth length, confirming their interaction with intrauterine growth. T1D children were taller, but not heavier, at birth than non-HLA matched controls, but not compared to HLA matched ones. T1D children showed increased height development during the first 18 months compared to both non-HLA and HLA matched controls. Thus, other factors than HLA-genotypes are concluded to be responsible for the increased linear growth before T1D onset. In paper IV parental reactions to DiPiS was studied. Most parents were not worried by participation in our study.