Association of TC/HDL-C Ratio with Incident Hip Fracture Risk in Middle-Aged and Older Chinese Adults: A Prospective Cohort Study

Hip fracture, a severe complication of osteoporosis, imposes a heavy burden on aging populations. Evidence on the association between the total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) ratio and hip fracture risk in Chinese middle-aged and older adults is limited. We enrolled 8,407 participants aged ≥ 45 years from the China Health and Retirement Longitudinal Study (2011–2020) without prior hip fracture and with complete lipid data. Participants were categorized by quartiles of the baseline TC/HDL-C ratio. Kaplan–Meier analysis, Cox proportional hazards regression, and restricted cubic spline (RCS) models were applied. During follow-up, 373 incident hip fractures occurred (cumulative incidence 4.44%). In the fully adjusted model, the highest quartile (Q4, ≥ 4.80) was associated with a 28% lower hip fracture risk compared with the lowest quartile (Q1, < 3.10) (HR = 0.72, 95% CI: 0.53–0.98, P  = 0.037). RCS analysis confirmed a significant nonlinear association ( P for nonlinearity = 0.049). Age, sex, and BMI did not significantly modify the association. An elevated TC/HDL-C ratio is independently associated with a lower risk of hip fracture in Chinese middle-aged and older adults, showing a nonlinear dose–response pattern. This ratio may serve as a supplementary biomarker for early hip fracture risk screening.