The relationship between the a body shape index and benign prostatic hyperplasia in middle-aged and elderly adults: a nationwide cohort study

Abstract Objective This study investigates the association between A Body Shape Index (ABSI) and risk of benign prostatic hyperplasia (BPH) in middle-aged and older men. Methods Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS), including 3,223 men aged ≥ 45 years. ABSI was calculated from waist circumference, BMI, and height. Logistic regression and restricted cubic spline models were used to assess the association and potential nonlinear relationship between ABSI and incident BPH. Results During 4 years of follow-up, 260 new BPH cases were identified. A nonlinear association was observed: ABSI was significantly associated with increased BPH risk within a moderate range (7.420–8.916), but not at lower or higher ABSI levels (OR = 1.532, 95% CI: 1.015–2.314, p = 0.042). Conclusion ABSI was associated with BPH risk in a nonlinear pattern. These findings suggest that ABSI may serve as a potential risk indicator, although further research is needed. Limitations include reliance on self-reported BPH diagnosis and lack of biomarker data.