Associations of Serum TG with Bone Mineral Density and Lean Mass in Healthy Iranian Adolescents

Abstract

Background: The association between triglyceride (TG) levels and bone health in adolescents remains inconsistent, and data from non-Western populations are scarce. Objectives: This study was the first to examine the association between TG levels and dual-energy X-ray absorptiometry (DXA)-derived bone parameters in healthy Iranian youth. Methods: In this cross-sectional study, 478 adolescents (241 boys and 237 girls; aged 9 - 18 years) from Kawar, Iran, underwent anthropometric measurements, fasting TG profiling, and whole-body DXA scans. Univariate and multivariable linear regression analyses were used to evaluate associations between TG levels, expressed per 1-standard deviation (SD) increase, and bone area (cm2), bone mineral content (BMC; g), bone mineral density (BMD; g/cm2), and lean mass (g), with sequential adjustment for age, sex, vitamin D3, and pubertal status according to Tanner stage. Results: The mean TG level was 74.99 ± 51.92 mg/dL. Univariate analyses showed positive associations for 22 of 29 parameters, with the strongest associations observed for pelvic BMD (β = 0.19; 95% CI, 0.11 - 0.28; P < 0.0001) and total lean mass plus BMC (β = 0.17; 95% CI, 0.08 - 0.26; P = 0.0002). In fully adjusted models, significant associations were retained for total BMD (β = 0.08; P = 0.004), pelvic BMD (β = 0.14; P < 0.001), femoral neck BMD (β = 0.11; P = 0.007), and total lean mass (β = 0.10; P < 0.001), with puberty largely explaining the attenuation. Conclusions: Higher TG levels, expressed per 1-SD increase equivalent to 52 mg/dL, were positively associated with adolescent bone mineralization and lean mass accrual, independent of measured confounders. These findings suggest a favorable cross-sectional association during growth. These ethnicity-specific findings highlight cardiometabolic-bone interactions and support the hypothesis that TG levels should be considered in future longitudinal studies of skeletal health in youth. Owing to the cross-sectional design, causal inferences cannot be drawn.