Association of CHI3L1 with bone turnover markers in Iraqi postmenopausal women with osteopenia and osteoporosis

Introduction Chitinase-3-like protein 1 (CHI3L1) has been implicated in bone remodeling, but its relationship with bone turnover markers across different degrees of postmenopausal bone loss remains unclear. This study evaluated CHI3L1 together with CTX-1, NTX-1, and osteonectin (OSN) in Iraqi postmenopausal women with osteopenia (ON) and osteoporosis (OP). Materials and Methods Ninety postmenopausal women aged 45–65 years were classified into control, ON, and OP groups ( n = 30 each) according to lumbar spine BMD and T-scores. Serum biomarkers were measured by ELISA. Group differences were assessed by one-way ANOVA with Tukey's HSD test. Pearson correlations were adjusted using the Benjamini–Hochberg false discovery rate, and multivariable regression was used to evaluate associations with BMD after adjustment for age, BMI, WHpR, and WHtR. ROC analysis assessed discriminatory performance. Results CHI3L1 and NTX-1 increased progressively from controls to ON and OP, whereas OSN decreased. CTX-1 was elevated in ON and OP versus controls but did not differ between ON and OP. CHI3L1, CTX-1, and NTX-1 were inversely associated with BMD, whereas OSN was positively associated (all p < 0.001). CTX-1 showed the highest AUC for ON versus controls (0.974), while NTX-1 showed the highest AUC for OP versus controls (0.999) and OP versus ON (0.968). Conclusion These biomarkers showed distinct associations with skeletal status and BMD. CHI3L1 may provide complementary information alongside established bone turnover markers, while NTX-1 exhibited the highest observed AUC for OP in this cohort. Larger independent studies are required for validation.