β-cell function (HOMA-β)

HOMA-β (Homeostatic Model Assessment of Beta-cell function) is a fasting-state surrogate for pancreatic β-cell insulin-secretory capacity, calculated as (20 × fasting insulin in µU/mL) / (fasting glucose in mmol/L − 3.5). It reflects predominantly basal insulin secretion and correlates modestly with more demanding assessments such as the disposition index from intravenous glucose tolerance tests, though it cannot capture dynamic glucose-stimulated secretion. β-cell mass and secretory function decline progressively with age and are accelerated by insulin resistance, glucolipotoxicity, and chronic low-grade inflammation. Monitoring HOMA-β alongside HOMA-IR provides a paired view of both demand and supply within the glucose-regulation axis, relevant to prediabetes risk stratification and longevity-oriented metabolic assessment.