For example, a study of Karras et al.’s [159] compared the glucose/insulin profile of 20 individuals diagnosed with normocalcemic hyperparathyroidism and prediabetes versus controls with prediabetes and found similar levels of A1c glycated hemoglobin, HOMA-IR, serum insulin, and glucose levels at 2 h after the 75 g oral glucose test but higher fasting glucose (p = 0.01) that was positively correlated with PTH (rho coefficient of 0.374, p = 0.005) [159]. Here, INS is linked to hyperparathyroidism.