Association Between Baseline C-reactive Protein–Triglyceride–Glucose Index and Incident Asthma: A Prospective Cohort Study from the CHARLS

Although insulin resistance and chronic inflammation individually contribute to airway disorders, the prospective risk of asthma associated with their joint burden remains unquantified. This study evaluated the prospective association between the baseline C-reactive protein–triglyceride–glucose (CTI) index and incident asthma using a nationwide cohort of 12,359 middle-aged and older adults from the China Health and Retirement Longitudinal Study (CHARLS). Over a median follow-up of 7 years, 456 participants developed asthma. Multivariable Cox proportional hazards models showed that each 1-unit increase in baseline CTI was associated with an increased risk of incident asthma (HR 1.17; 95% CI, 1.02–1.34). Fine–Gray competing-risk models adjusting for the competing risk of death yielded consistent results (sHR 1.18; 95% CI, 1.05–1.33). In stratified analyses, the association was present in participants without diabetes (HR 1.22; 95% CI, 1.04–1.43) but absent in those with prevalent diabetes. Baseline CTI may serve as an accessible biomarker for identifying individuals at increased risk of future asthma, highlighting the contribution of metabolic-inflammatory dysregulation to asthma development.