Objective To explore the time cross-lagged effect between carotid intima-media thickness(CIMT)and bone mineral density(BMD)and to assess whether CIMT can be used as an early predictor of osteoporosis.Methods Based on the retrospective cohort study involved,people who underwent health checkups at The First Affiliated Hospital of Xi'an Jiaotong University from January 2019 to December 2023 were selected,and data related to CIMT and BMD were collected.The time-series relationship between CIMT and BMD was explored by cross-lagged modeling.Meanwhile,the effects of CIMT on BMD and its dose-response relationship were assessed using multiple linear regression and restricted cubic spline regression models.Results Analysis of 2 453 study subjects revealed a significant negative relationship between prior physical examination CIMT and subsequent BMD,and this relationship remained significant after controlling for confounders.For every 1-unit increase in CIMT,there was a mean decrease in second-stage BMD T-values of 0.113.Restricted cubic spline regression analysis showed a maximum decrease in BMD T-values of 0.121 for every 1.00 mm increase in CIMT.Conclusion The present study found that there was a significant negative cross-lag effect between CIMT and BMD,and that there was a dose-response between an increase in CIMT and a decrease in BMD.CIMT,as an easy-to-measure indicator,may be a potential marker for early prediction of osteoporosis,especially in the elderly population.