INS and type 1 diabetes mellitus: PDR and DKD were absent in type 1 diabetes patients carrying the protective INS variant and receiving intensive insulin therapy (the current standard of clinical care) 1–5 years from their diagnosis (n = 67; mean post-diagnosis follow up of 20.4 ± 1.6 years), versus 11 of 258 patients (4.3%) lacking this variant (20.4 ± 1.8 years follow up).