Importance Dietary proteins, such as gluten, have been suggested as triggers of the disease process in type 1 diabetes (T1D). Objectives To study the associations of cereal, gluten, and dietary fiber intake with the development of islet autoimmunity (IA) and T1D. Design Prospective birth cohort, the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Study recruited children with genetic susceptibility to type 1 diabetes from 1996 to 2004 and followed them every 3-12 months up to 6 years for diet, islet autoantibodies and T1D. Setting Two university hospitals in Finland Participants Altogether 6081 infants participated in the study (78% of those invited). Dietary data was available on 5714 children, and both dietary and IA data on 5545 children, of whom, 68% had data on islet autoantibodies up to 6 years of age. Information on T1D was available for all children. Exposures The child's intake of cereals, gluten, and dietary fiber was calculated from repeated 3day food records up to 6 years. Main outcome measures IA was defined as repeated positivity for islet cell antibodies and at least one biochemical autoantibody out of three ones analysed, or T1D. Data on diagnosis of T1D was obtained from Finnish Pediatric Diabetes Register. Results Of the 5545 children (53.2% boys), 246 developed IA and of the 5714 children, 90 developed T1D during the 6-year follow-up. Based on joint models, the intake of oats (HR 1.08

Aims/hypothesis Our aim was to study the association between serum 25-hydroxyvitamin D (25OHD) concentration and islet autoimmunity and type 1 diabetes in children with an increased genetic risk of type 1 diabetes. Methods Serum samples for 25OHD measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children in 15 countries. Case children (n = 244) were defined as having positivity for at least two out of four diabetes-associated autoantibodies measured at any one sample. For each case child, two control children were selected matched for country and date of birth (±1 year) (n = 488). Of the case children, 144 developed type 1 diabetes. Serum 25OHD was measured repeatedly in infancy and childhood and was compared according to age at the first seroconversion (at 6, 12 and 18 months prior to and at seroconversion) and calendar age (0, 6, 12 and 18 months). Results In children with islet autoimmunity, mean serum 25OHD concentration was lower 18 months prior to the age of first seroconversion of the case children compared with the control children (57.7 vs 64.8 nmol/l, p = 0.007). In children with type 1 diabetes (n = 144), mean serum 25OHD concentration was lower 18 months prior to the age of the first seroconversion (58.0 vs 65.0 nmol/l, p = 0.018) and at the calendar age of 12 months (70.1 vs 75.9 nmol/l, p = 0.031) than in their control counterparts. Analyses were adjusted for month of sample collection, human leucocyte antigen genotype, maternal type 1 diabetes and sex. Conclusions/interpretation The results suggest that early postnatal vitamin D may confer protection against the development of type 1 diabetes. Trial registration ClinicalTrials.gov NCT00179777Electronic supplementary material The online version of this article (