Introduction:​ Insulin resistance (IR) is closely associated with cardio-metabolic diseases. However, the impact of IR on bone mass remains obscure. The present study is to evaluate the association between the triglyceride-glucose (TyG) indicated IR and bone mass in a nationwide health check-up population in China.

Methods:​ We conducted a retrospective cross-sectional study including 788,247 participants and a longitudinal cohort study in 8770 participants who had repeated measurements of TyG index and bone mass in at least a 2-year follow-up period. The restricted cubic splines and logistic models were used to analyze the association between IR and bone mass in the cross-sectional study. The Cox model was applied to evaluate the relationship between baseline IR and the subsequent incidence of low bone mass and osteoporosis in the longitudinal study.

Results:​ In the cross-sectional study, the TyG index had positive correlations with low bone mass, osteoporosis, or both after adjusting for confounding factors (all P < 0.001). In the longitudinal cohort study, the baseline TyG index was significantly associated with the incidence of low bone mass, osteoporosis, or both during the follow-up period, with hazard ratios (HRs) of 1.56 (95 % confidence interval [CI]:​ 1.25, 1.93, P < 0.05), 1.66 (95%CI:​ 1.06, 2.59, P < 0.05), and 1.55 (95%CI:​ 1.27, 1.88, P < 0.05) after adjusting for confounding factors, respectively.

Conclusions:​ These results suggest that IR indicated by TyG is significantly associated with an increased risk of low bone mass and osteoporosis. Therefore, bone mass monitoring and early prevention strategies may be needed in individuals with IR to prevent the occurrence of low bone mass and osteoporosis.