To investigate the relationship of metabolic score for insulin resistance (METS-IR) with bone mineral content (BMC) and bone metabolic markers levels among adolescents, so as to provide a scientific foundation for the early identification and prevention of bone-related diseases.

From 2017 to 2019 and 2023, a total of 1 414 adolescents aged 12-18 years from Yinchuan were selected using a method combining convenient sampling with stratified cluster random sampling. The data of basic information, body mass index, BMC, serum osteocalcin (OC), type Ⅰ collagen cross-linked C-terminal peptide (CTX) and calcium (Ca), METS-IR among adolescents were obtained by questionnaire survey, physical measurement and laboratory examination, and METS-IR was divided into four groups Q1-Q4 according to P₂₅, P₅₀ and P₇₅. Logistic regression models combined with restricted cubic splines were employed to analyze the relationship between METS-IR and low BMC as well as low bone metabolic markers. The receiver operating characteristic (ROC) curve was used to evaluate METS-IR effectiveness in diagnosing low BMC.

The levels of BMC, OC, CTX, Ca and METS-IR in the surveyed adolescents were (2.66±0.52)kg, (20.49±13.77)ng/mL, (2 460.89±1 818.96)pg/mL, (2.47±0.67)mmol/L, 30.63±7.58. After adjusting for gender, age and physical activity level, METS-IR in Q4 group had a reduced risk of low BMC and low CTX [OR (95%CI)=0.03(0.01-0.07), 0.45(0.32-0.65)] and an elevated risk of low OC [OR (95%CI)=1.85(1.28-2.67)], compared with the Q1 group (all P < 0.05). Gender-stratified analyses revealed similar trends for both males and females (all P < 0.05). Non-linear dose-response relationships were observed between METS-IR and low BMC (P_{total trend} < 0.01, P_{non-linearity}=0.01), as well as low OC (P_{total trend} < 0.01, P_{non-linearity}=0.01), while a linear relationship was detected with low CTX (P_{total trend} < 0.01, P_{non-linearity}=0.72). ROC curves revealed that METS-IR had the best diagnostic performance for low BMC (AUC=0.85, 95%CI=0.82-0.88, P < 0.01).

Higher METS-IR score is linked to reduced risk of low BMC and CTX but increase risk of low OC among adolescents. These findings suggest METS-IR is a reliable indicator for assessing BMC and early predicting bone health risk among adolescents.