INS and type 1 diabetes mellitus: We used the Illumina EPIC array to determine the methylation status of blood DNA samples collected from 1,752 children participating in two prospective longitudinal studies, BABYDIAB/BABYDIET and Primary Oral Insulin Trial (POInT), including 790 children who had a mother with T1D (Supplementary Table 1 and Extended Data Fig. 1a,b).