Association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and bone mineral density in the lumbar spine: A cross-sectional and mediation analysis

Osteoporosis, characterized by low bone density and disrupted bone structure, increases fracture risk. While the link between bone mineral density (BMD) and various health factors, including lipid metabolism, is widely studied, the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) has not been extensively explored in relation to BMD. This study aims to investigate the association between NHHR and lumbar spine BMD, considering the potential mediating role of body mass index (BMI). We analyzed 9054 participants from the National Health and Nutrition Examination Survey (2011-2018) using multivariate linear regression, generalized additive models, and mediation analysis. Subgroup and threshold effect analyses were also conducted. A negative correlation between NHHR and lumbar spine BMD was found, with significant nonlinear relationships and threshold effects. This association was stronger in individuals aged ≤ 50 years, especially those who were nondiabetic and engaged in moderate recreational activities. Mediation analysis indicated that BMI partially mediates this relationship, explaining 35.8141% of the association. This study reveals a U-shaped relationship between NHHR and lumbar spine BMD and highlights the role of BMI in this association. Managing NHHR-related lipid levels and BMI is crucial for osteoporosis prevention, particularly in younger, nondiabetic populations.