The correlation between the serum LDL-C/Apo B ratio and lumbar bone mineral density in young adults

BACKGROUND: Numerous studies have confirmed that atherosclerosis is related to osteoporosis (OP), and patients with atherosclerosis are more prone to OP. The ratio of low-density lipoprotein cholesterol (LDL-C) to apolipoprotein B (Apo B) is the valid indicator of atherosclerosis. Nevertheless, conclusions regarding relation between LDL-C/Apo B ratio and bone mineral density (BMD) are still lacking. As a result, this study concentrated on investigating the relationship between LDL-C/Apo B ratio and lumbar BMD in the young adult population according to the National Health and Nutrition Examination Survey (NHANES). METHODS: Information of 2027 young adults (age 20–40 years) from NHANES database was obtained for this cross-sectional study. The correlation between serum LDL-C/Apo B ratio and lumbar BMD was explored through weighted multiple stratified linear regression, while the smooth curve fitting model was utilized for analyzing nonlinear relation. In the nonlinear relation, the inflection point was calculated by saturation threshold analysis. The weighted two-piecewise linear regression model was constructed. RESULTS: After covariates were adjusted, the relation between serum LDL-C/Apo B ratio and lumbar BMD varied by sex (males: β = -0.0126, 95% CI -0.0892, 0.0640; females: β = 0.0322, 95% CI -0.0367, 0.1011). By performing age-stratified subgroup analysis, the association also varied by age and sex. Males aged 20–30 years presented a negative trend (β = -0.0570, 95% CI -0.1656, 0.0517), and males with the age of 31–40 years showed a positive trend (β = 0.0810, 95% CI -0.0312, 0.1931). Women showed a positive trend by age (females of 20–30 years: β = 0.0051, 95% CI -0.0935, 0.1036; females of 31–40 years: β = 0.0265, 95% CI -0.0767, 0.1296). In race-stratified subgroup analysis, the relations varied by sex and race. To be specific, non-Hispanic black males showed a negative trend (β = -0.0754, 95% CI -0.2695, 0.1188), and males of other races exhibited a positive trend. The trend was positive for women of all races. CONCLUSION: Differences were detected in the association between serum LDL-C/Apo B ratio and lumbar BMD among cases aged 20–40 years across sex, age, and race/ethnicity. In addition, the inflection points in U-shaped relationships were also calculated. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-023-06325-w.