The triglyceride-to-HDL cholesterol ratio is associated with lower BMD in older adults at high altitudes: a retrospective retrospective cross sectional study

Purpose: Focusing on older adults living in high-elevation areas, this study aimed to examine the association between the TG/HDL-C ratio and the odds of low bone mineral density (BMD), providing evidence to support bone health management in this special environment. Methods: In this retrospective analysis conducted at our Hospital, we recruited 650 older adults residing in high-elevation regions between December 2022 and December 2024. Baseline characteristics were gathered using a combination of questionnaires, physical assessments, and laboratory tests. Bone mineral density (BMD) at the lumbar spine (L1-L4) and femoral neck was evaluated via dual-energy X-ray absorptiometry (DXA). Subjects were stratified into quartiles based on their TG/HDL-C ratios. To assess the link between these ratios and the likelihood of low BMD, we employed multivariate logistic regression, while restricted cubic spline (RCS) modeling and stratified analyses were utilized to examine dose-response patterns and ensure result stability. Results: As the TG/HDL-C ratio increased, participants tended to have less favorable metabolic profiles, accompanied by lower lumbar spine and femoral neck BMD values (P<0.001). The prevalence of low BMD increased from 35.8% in Q1 to 61.3% in Q4 (P<0.001). After adjusting for potential confounders (age, sex, BMI, lifestyle factors, hypertension, diabetes, and hemoglobin), a higher TG/HDL-C ratio was independently associated with higher odds of low BMD. Compared with Q1, Q4 showed higher odds of low BMD in the lumbar spine (OR = 2.86, 95%CI: 1.72-4.75; P for trend=0.003) and femoral neck (OR = 3.55, 95%CI: 1.65-7.62; P for trend=0.005). Restricted cubic spline analyses suggested a significant non-linear association between the TG/HDL-C ratio and the odds of low BMD at both sites (non-linear P = 0.021 for lumbar spine; 0.045 for femoral neck), with steeper increases in odds when the ratio exceeded approximately 1.5 and 2.0, respectively. Subgroup analyses showed consistent associations across age, sex, BMI, and comorbidity strata. Conclusion: Among older adults living at high altitudes, a higher TG/HDL-C ratio was associated with lower BMD in the lumbar spine and femoral neck, with a non-linear pattern. The TG/HDL-C ratio may serve as a practical marker to help identify individuals with a higher probability of low BMD in this setting.