High one-hour plasma glucose is an intermediate risk state and an early predictor of type 2 diabetes in a longitudinal Korean cohort.

Abstract

Aims: Because one-hour post-load plasma glucose (1h-PG) ≥ 155 mg/dL (8.6 mmol/L) has been proposed as an early marker for future diabetes but lacks sufficient longitudinal confirmation of its risk, we aimed to evaluate the risk of T2D based on 1h-PG and track changes of insulin sensitivity and β-cell function over time by 1h-PG in a longitudinal cohort.

Methods: OGTTs were conducted every 2 years in the 10-year longitudinal Korean Genome Epidemiology study (n = 6144) with three groups characterized at baseline: Low 1h-PG (< 155 mg/dL) with Normal Glucose Tolerance (NGT), High 1h-PG (≥155 mg/dL) with NGT, and prediabetes (PreDM).

Results: T2D risk was higher in people with High 1h-PG with NGT and PreDM than those with Low 1h-PG with NGT. Baseline insulin sensitivity in Low 1h-PG as measured by the insulin sensitivity and secretion (ISS) model and Matsuda insulin sensitivity index (ISI) was higher than in High 1h-PG, which was comparable to PreDM. β-cell function as assessed by ISS and the insulinogenic index decreased from Low 1h-PG to High 1h-PG to PreDM. Over time, insulin sensitivity decreased in the three groups. Time from High 1h-PG to T2D was 0.9 years shorter than from Low 1h-PG. All participants passed the 1h-PG threshold for T2D (209 mg/dL, 11.6 mmol/L) first, and 74 % passed the 1h-PG threshold for impaired glucose tolerance (IGT; 155 mg/dL) first.

Conclusions: High 1h-PG NGT is an intermediate risk category between Low 1h-PG NGT and PreDM and may provide an opportunity for early intervention to prese rve ß-cell function.