These findings are probably less relevant in TM patients because the IGF-1 levels are < −2SDs in 50% of patients compared to healthy individuals 44 and the prevalence of DR remains low for a long duration of diabetes, however, we cannot ignore this point because it suggests that another particular risk factor for the progression of DR is represented by the upregulation of serum IGF-1. This evidence concerns the gene IGF1 and diabetes mellitus.