Lifestyle intervention is more effective in high 1-hour post-load glucose than in prediabetes for restoring β-cell function, reducing ectopic fat, and preventing type 2 diabetes

BACKGROUND: High 1-h-post-load plasma glucose (1 h-PG) is an early diabetes risk marker. We hypothesized that isolated high 1 h-PG represents an intermediate state between normal glucose regulation (NGR) and impaired glucose regulation (IGR) and is amendable to greater lifestyle intervention (LI) benefit. METHODS: In the Tübingen Lifestyle Intervention Program, 317 people with either NGR, IGR or isolated high 1 h-PG without IGR underwent LI for 9 months to achieve ≥5 % weight loss. RESULTS: Before LI initiation, insulin sensitivity and β-cell function declined progressively from NGR (n = 106) to high 1 h-PG (n = 96) and to IGR (n = 115). Visceral adipose tissue (VAT) volume and liver fat content increased from NGT to high 1 h-PG and to IGR. LI improved insulin sensitivity and ß-cell function in the high 1 h-PG group to levels observed in NGR together with a marked reduction in hepatic fat content. Compared to the IGR group, T2D risk was reduced by 80 % (37-96 %, p = 0.005) in the high 1 h-PG group during a 12-year follow-up period. The odds of remission to complete normoglycemia were doubled in the high 1 h-PG group compared to the IGR group (2.18 [1.13-4.28], p = 0.021). CONCLUSION: High 1 h-PG indicates an intermediate metabolic state with pathophysiological changes more severe than in NGR but milder than in IGR. In people with high 1 h-PG, LI significantly improved insulin sensitivity and β-cell function and reduced ectopic lipid deposition and the risk of developing T2D compared to IGR. These findings highlight the value of 1 h-PG as a clinically useful biomarker, providing a critical window for early intervention to reverse core metabolic defects driving prediabetes and T2D.