C-reactive protein-triglyceride glucose index and risk of cognitive decline in Chinese middle-aged and older adults: A 9-year national cohort study from CHARLS

Background Cognitive decline is a pressing global health issue in aging populations. The novel composite biomarker, C-reactive protein-triglyceride glucose index (CTI), may provide a superior tool for early risk stratification. Objective This study examined CTI's capacity to independently predict cognitive decline. Methods This retrospective cohort analysis utilized data from 5464 middle-aged and older adults without baseline cognitive impairment from the China Health and Retirement Longitudinal Study (CHARLS). The incidence of cognitive decline served as the primary outcome. CTI was calculated as: CTI = 0.412× Ln (CRP [mg/L]) + Ln (TG [mg/dl] ×FPG [mg/dl])/2. Cognitive performance was assessed in 2020 using the Chinese Mini-Mental State Examination (MMSE). Logistic regression and complementary approaches were used to analyze associations. Results Over the 9-year follow-up, a significant positive association between CTI and cognitive decline risk was observed. After multifactorial adjustment, individuals in the highest CTI quartile (Q4) demonstrated a 34% elevated risk relative to the lowest quartile (Q1) (HR = 1.34, 95%CI: 1.10–1.63; p = 0.004). A monotonic dose-response gradient was evident (p = 0.005), with restricted cubic splines confirming linearity (p = 0.025). Sensitivity analyses substantiated robustness. Conclusions Elevated CTI is independently associated with increased risk of cognitive decline, suggesting its potential as a dual-pathway biomarker for early screening.