U-shaped association between TC/HDL-C ratio and osteoporosis risk in older adults.

This study aimed to evaluate the association between the total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) ratio and the risk of osteoporosis in older adults. A cross-sectional analysis was conducted using data from 7,465 individuals aged 60 and above from the 2005-2020 National Health and Nutrition Examination Survey (NHANES). The TC/HDL-C ratio was calculated and divided into quartiles. Osteoporosis was defined by self-reported physician diagnosis or dual-energy x-ray absorptiometry (DXA) measurements. Multivariable logistic regression models assessed the association between the TC/HDL-C ratio and osteoporosis prevalence. Restricted cubic splines were used to explore non-linear associations and threshold effects. Among the participants, 1,608 had osteoporosis. A higher TC/HDL-C ratio was inversely associated with osteoporosis (OR: 0.92, 95% CI: 0.86-0.99, p = 0.02). The analysis revealed a U-shaped association (p for nonlinearity = 0.005) with a threshold at 4.66. Below this threshold, the TC/HDL-C ratio was negatively associated with osteoporosis (OR: 0.83, 95% CI: 0.72-0.94, p = 0.010), while no significant association was observed above the threshold. In sex-specific analyses, a U-shaped relationship was found in women, with a threshold at 4.35 (p for nonlinearity = 0.0016), but no significant association was found in men. The TC/HDL-C ratio demonstrates a U-shaped association with osteoporosis risk in older adults, particularly in women. Further longitudinal studies are required to validate these findings and determine optimal lipid management strategies for osteoporosis prevention.