Association between the psychological frailty index and stroke: a cohort study from CHARLS

Stroke is a leading cause of death and disability worldwide, especially in the aging population. Psychological vulnerability serves as a multidimensional mental health vulnerability state, but there is a lack of large sample studies on its association with stroke. The aim of this study was to investigate the relationship between psychological vulnerability, as quantified by the Psychological Frailty Index, and stroke. This study was based on baseline data from the China Health and Retirement Longitudinal Study (CHARLS), which included 15,284 participants ≥ 45 years of age. PFI was used as a composite measure of psychological vulnerability by quartiles. Stroke was analyzed using Cox logistic regression models to analyze the relationship between PFI and stroke risk, and the dose-response relationship was tested using restricted cubic spline (RCS). Subgroup analyses and interaction tests were performed to assess differences in different populations. In the fully adjusted Cox model, each one-IQR increase in PFI was associated with an 87% higher risk of incident stroke (HR = 1.87, 95% CI 1.54-2.27; P < 0.001). Compared with participants in the lowest PFI quartile (Q1), those in the highest quartile (Q4) exhibited a more than three-fold increased stroke risk (HR = 3.12, 95% CI 1.99-4.91; P < 0.001). Restricted cubic spline analysis demonstrated a linear dose-response relationship between PFI and stroke risk (P for nonlinearity > 0.05). In subgroup analyses, the association between PFI and stroke was significantly modified by age and marital status (P for interaction < 0.05). In this study, we found that psychological vulnerability was significantly positively and linearly associated with stroke risk. Assessment of psychological vulnerability may be an important component of a comprehensive stroke prevention and control strategy, with particular attention to the elderly and those with social support deficits. Future longitudinal studies should be conducted to clarify the causal relationship.