Longevity & Aging · Metabolic & Cardiometabolic
dynamic insulin testing OGTT-with-insulin CGM fasting insulin detects insulin resistance years before fasting glucose or HbA1c become abnormal
In plain terms: Can measuring insulin catch metabolic trouble years before a standard glucose test does?
Part of: • Insulin & Metabolic Aging
Probably, but it rests on one cohort. Whitehall II shows insulin sensitivity falling and compensatory insulin rising three to five years before fasting glucose or HbA1c turn abnormal, and trajectory analyses agree. Almost all of that evidence comes from that single cohort, so earlier detection is not established rather than proven — and glucose markers still carry real predictive signal of their own.
📅 Last reviewed: 2026-07-14 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Population patterns (Observational)
How the studies fall
What the evidence shows
Whitehall II shows insulin sensitivity falling and compensatory insulin rising three to five years before fasting glucose or HbA1c turn abnormal, with trajectory analyses agreeing. Nearly all of it is that one cohort, so independent confirmation is missing, and the ARIC data show glucose markers carry real predictive signal of their own.
The evidence (4)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Rawlings AM, Sharrett AR, Mosley TH, Ballew SH, Deal JA, Selvin E 2017 · Diabetes Care | observational | tested-null | moderate | ARIC: glucose peaks/HbA1c do predict long-term dementia/decline — showing glucose markers carry real signal too, so insulin testing is earlier but glucose is not uninformative. |
| Tabák AG, Jokela M, Akbaraly TN, Brunner EJ, Kivimäki M, Witte DR 2009 · Lancet | observational | supports | high | Whitehall II: in those developing T2DM, insulin sensitivity fell and compensatory hyperinsulinemia rose 3-5+ years before diagnosis, with fasting glucose staying near-normal until a late steep rise. |
| Færch K, Witte DR, Tabák AG, Perreault L, Herder C, Brunner EJ, Kivimäki M, Vistisen D 2013 · Lancet Diabetes Endocrinol | observational | supports | high | Whitehall II subtype analysis: distinct pre-diagnosis trajectories of insulin sensitivity/secretion, confirming metabolic dysfunction is detectable well before glucose-based diagnosis. |
| Hulman A, Simmons RK, Brunner EJ, Witte DR, Færch K, Vistisen D, Ikehara S, Kivimaki M, Tabák AG 2017 · Diabetologia | observational | supports | moderate | Trajectory modeling shows insulin-sensitivity/secretion changes precede diabetes and differ by ethnicity — earliest divergence is in insulin dynamics, not fasting glucose. |
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