The atherogenic index of plasma and triglyceride glucose-body mass index are inversely associated with cognitive impairment in middle-aged and older Chinese adults: A community-based cohort study

Background Although metabolic disorders are associated with cognitive dysfunction, the relationship with composite metabolic indices remains unclear. Objective This study aimed to examine the longitudinal associations of the atherogenic index of plasma (AIP) and the triglyceride-glucose body mass index (TyG-BMI) with incident cognitive impairment in a community-based cohort of middle-aged and older adults. Methods This prospective cohort study included 1492 cognitively normal adults (age ≥40 years). Baseline AIP and TyG-BMI were calculated from blood samples. Incident cognitive impairment was defined using education-specific Mini-Mental State Examination cut-offs at a 2-year follow-up. Associations were evaluated using multivariable logistic regression (adjusted for age, sex, education, apolipoprotein E ε4, and other confounders) and restricted cubic spline models. Results Among participants, 59.4% were female, with a median age of 55 years (IQR, 48–63). Over a median follow-up of 2.02 years (IQR, 1.98–2.06), 133 participants (8.9%) developed cognitive impairment. After full adjustment, higher levels of AIP (OR = 0.21, 95% CI: 0.09–0.50) and TyG-BMI (OR = 0.99, 95% CI: 0.98–0.99) were inversely associated with the risk of cognitive impairment (both p < 0.001). A dose-response relationship was observed, with risk decreasing as index levels increased. Conclusions In this middle-aged and older Chinese cohort, higher AIP and TyG-BMI were associated with a reduced short-term risk of cognitive impairment. These findings highlight the complex, context-dependent nature of metabolic-cognitive associations, suggesting these indices may reflect a metabolic profile relevant to early cognitive maintenance.