INS and type 1 diabetes mellitus: A similar cohort of first- and second-degree relatives of people with T1D underwent assessments of the contribution of insulin resistance (mathematical modeling of glucose/C-peptide responses after OGTT) and β-cell glucose sensitivity (slope of the insulin secretion/plasma glucose dose–response function) every 6 months for 3 years until the onset of hyperglycemia and disease progression (90).