Atherogenic index of plasma and its 5-year changes associated with type 2 diabetes risk: a 10-Year cohort study

The global burden of type 2 diabetes mellitus (T2DM) is increasing, particularly in resource-limited settings like rural China. Although traditional blood glucose remains an essential measurement for diabetes screening, Atherogenic Index of Plasma (AIP) is emerging as a complementary predictor of T2DM risk. Over time, however, the association between AIP and T2DM risk remains insufficiently understood. To investigate the association between baseline AIP levels and its 5-year changes with the risk of T2DM in a rural Chinese cohort. This prospective cohort study enrolled 14,968 participants without baseline diabetes from a rural Chinese population. AIP was calculated (log(TG/HDL-C)) and used to classify participant results into quartiles. We conducted multivariate Cox proportional hazards regression analysis, restricted cubic spline analyses, subgroup analyses, and sensitivity analyses to determine the association between baseline AIP and 5-year changes in AIP with the 10-year risk of T2DM. Over a median follow-up of 10.4 years, 2,165(N = 14,968) participants developed T2DM. The hazard ratios aHRs; 95% confidence interval (CI) for T2DM increased with quartiles 2, 3, and 4 (versus quartile 1) of AIP: 1.17 (1.00–1.38), 1.38 (1.18–1.62), and 1.96 (1.68–2.29), respectively (p for trend < 0.0001) after multivariable adjustment. Regarding 5-year changes in AIP, participants with increased AIP levels had a 18% higher risk of developing T2DM (aHRs 1.18, 95% CIs: 1.00–1.40) compared to those maintaining stable levels, while those with decreased AIP showed a 20% reduction in risk (aHRs 0.80, 95% CIs: 0.67–0.95). RCS analyses showed linear relationships for both baseline AIP (p for nonlinearity = 0.927) and 5-year changes in AIP (p for nonlinearity = 0.083) with T2DM risk. Our findings indicate that both baseline AIP levels and the 5-year changes in those levels are significantly associated with the risk of T2DM. Individuals with higher baseline AIP or 5-year increases in AIP were more likely to develop T2DM.