What role does HbA1c play in longevity?

HbA1c (glycated hemoglobin) reflects average blood glucose over 2–3 months. Elevated levels (>6.5 %) indicate diabetes, which robustly shortens lifespan through cardiovascular, renal, and neurodegenerative complications. Even in the prediabetic range (5.7–6.4 %), risk of accelerated aging increases. Conversely, a stable low HbA1c (<5.7 %) is associated with better glycemic control and reduced biological aging. However, HbA1c is not a direct longevity test: factors like anemia, hemoglobin variants, or kidney disease can distort values. Moreover, aggressive lowering in older adults does not always improve outcomes. For longevity, a moderate, stable HbA1c within the healthy range appears optimal – combined with lifestyle factors such as diet, exercise, and stress management. Evidence comes from large cohorts and meta-analyses (human-strong). Caveat: A single HbA1c value should not replace a comprehensive medical assessment.