Abstract / Summary
Abstract Background Diabetes mellitus has become a major global public health burden, particularly in China. The platelet-to-high-density lipoprotein cholesterol ratio (PHR) has emerged as a novel inflammatory and metabolic biomarker associated with cardiometabolic risk. However, prospective evidence regarding its association with incident diabetes remains limited. This study aimed to investigate the association between PHR and the risk of incident diabetes among Chinese middle-aged and older adults. Methods This prospective cohort study used data from the China Health and Retirement Longitudinal Study (CHARLS) spanning from 2011 to 2020. A total of 5835 participants without diabetes at baseline (2011–2012) were included and followed up in 2013, 2015, 2018, and 2020. Participants were divided into four groups according to PHR quartiles. Kaplan-Meier survival analysis and Cox proportional hazards regression models were employed to evaluate the association between PHR and incident diabetes. Restricted cubic spline (RCS) regression was performed to explore potential linear and non-linear relationships. Subgroup and sensitivity analyses were conducted to assess the robustness of the findings. Results During a median follow-up of 116 months, 669 participants developed incident diabetes. Kaplan–Meier analysis revealed a significantly higher cumulative incidence of diabetes in higher PHR quartiles (log-rank p < 0.001). After multivariable adjustment, Cox regression showed that participants in the highest PHR quartile (Q4) had a significantly increased risk of diabetes compared with those in the lowest quartile (Q1) (adjusted hazard ratio (HR) = 1.41, 95% confidence interval (CI): 1.11–1.78, p = 0.004). RCS analysis indicated a positive linear relationship between PHR and diabetes risk (P for nonlinearity = 0.339). Subgroup analyses showed that the association was generally consistent across most subgroups. Sensitivity analyses, including use of a composite diabetes definition (Q4 vs Q1: HR = 1.30, 95% CI: 1.09–1.56) and multiple imputation, yielded consistent findings. Conclusions Elevated PHR levels were associated with an increased risk of incident diabetes among Chinese middle-aged and older adults. Component-specific analyses suggested that this association may be driven predominantly by HDL-C. PHR may represent a simple and routinely available candidate biomarker associated with incident diabetes risk; however, whether it provides information beyond HDL-C alone requires further investigation. Clinical trial registration Not applicable.