Association between metabolic-inflammatory indices and new-onset stroke: A longitudinal study based on CHARLS

Metabolic-inflammatory dysregulation contributes to atherosclerosis, endothelial dysfunction, and pro-thrombotic states that elevate cerebrovascular risk. To explore the association between metabolic inflammation and new-onset stroke, we investigated 4 emerging indicators - the C-reactive protein-triglyceride glucose index (CTI), platelet-to-high-density lipoprotein-cholesterol ratio (PHR), body roundness index (BRI), and a body shape index (ABSI) - and evaluated their relationships with new-onset stroke. Data were derived from the China Health and Retirement Longitudinal Study (CHARLS) waves of 2011 and 2018. A total of 7365 individuals aged 45 years and older were included in the follow-up cohort. Logistic regression models were used to examine the associations between selected indicators and new-onset stroke, with subgroup analyses stratified by gender. Smoothed curve fitting was used to explore potential nonlinear relationships. The models were adjusted for confounding factors, and sensitivity analyses were performed to assess the robustness of the findings. During the 7-year follow-up period, a total of 545 participants experienced an incident stroke. Across all 3 logistic regression models, CTI, BRI, and PHR were positively associated with increased stroke risk. In the fully adjusted model, participants in the highest quartile of CTI (Q4) had a significantly higher risk compared to those in the lowest quartile (Q1), with an odds ratio (OR) of 2.054 (95% confidence interval [CI]: 1.546-2.729). Similarly, the highest quartiles of BRI and PHR were also significantly associated with increased stroke risk, with BRI Q4 showing an OR of 1.721 (95% CI: 1.296-2.284) and PHR Q4 showing an OR of 1.562 (95% CI: 1.215-2.009). CTI showed the strongest association with incident stroke among the evaluated indicators and exhibited a nonlinear relationship with stroke risk. A data-derived inflection point was identified at CTI = 8.806. Below this value, higher CTI was significantly associated with increased stroke risk (OR = 1.925, 95% CI: 1.469-2.523). Gender-stratified analyses further confirmed a consistent positive association between CTI and stroke risk in both men and women. ABSI showed no significant association with incident stroke. CTI, BRI, and PHR were significantly and positively associated with new-onset stroke, with CTI showing the strongest association among the evaluated indicators. ABSI showed no significant association.