Objective:

To investigate how BMI influences the nonlinear relationship between AIP and the risk of prediabetes in a large cohort of Chinese adults.

Key Findings:

• 12,371 participants developed FPG-defined incident prediabetes during a median follow-up of 3.0 years, indicating a significant health concern.
• A significant interaction between AIP and BMI was observed (P for interaction < 0.001), suggesting BMI's critical role in this relationship.
• AIP was associated with prediabetes risk only in normal-weight and overweight participants, highlighting the need for tailored risk assessments.
• Nonlinear associations were identified with inflection points at AIP = -0.20 for normal-weight and AIP = 0.057 for overweight individuals, indicating specific thresholds for risk.

Interpretation:

The association between AIP and prediabetes risk is significantly modified by BMI, with notable nonlinear and threshold-dependent relationships primarily observed in normal-weight and overweight individuals.

Limitations:

• The study relied solely on FPG to define prediabetes, lacking HbA1c and OGTT data, which may limit the accuracy of prediabetes classification.
• The findings may not be generalizable beyond the Chinese population, necessitating further research in diverse populations.

Conclusion:

The study underscores the importance of considering BMI when assessing the risk of prediabetes associated with AIP, revealing significant nonlinear relationships in specific BMI categories that could inform clinical practice.