Atherogenic index of plasma and stroke risk across blood pressure strata in Chinese adults

This study investigated the association between the atherogenic index of plasma (AIP) and stroke risk across blood pressure (BP) strata, with exploratory assessments of the bidirectional mediating roles of body mass index (BMI) and AIP. We included 8,695 participants from the China Health and Retirement Longitudinal Study (CHARLS, 2011–2020). AIP was calculated as log₁₀(TG/HDL-C). Time-dependent Cox models were used to estimate the hazard ratios (HRs). Restricted cubic spline (RCS) and mediation analyses were performed. Higher AIP was independently associated with increased stroke risk (HR: 1.60, 95% CI 1.22‑2.09).This association was observed in both the high-normal BP (HR: 2.08, 95% CI 1.21‑3.59) and hypertension strata (HR: 1.47, 95% CI 1.03‑2.11), with no significant interaction by BP strata ( P = 0.660). RCS analysis showed a dose-response relationship between baseline AIP levels and stroke risk across all participants, high-normal BP, and hypertension strata. Exploratory mediation analysis suggested that BMI mediated 20.59% of AIP’s effect on stroke, while AIP mediated 20.52% of BMI’s effect. AIP is an independent risk factor for stroke, with no significant effect modification by BP strata. Exploratory mediation analyses suggest that integrating AIP screening with BMI management could be beneficial for stroke prevention, a finding that requires prospective validation.