The association between the ZJU index and bone mineral density (BMD) among patients with type 2 diabetes mellitus.

Background: Previous studies have suggested that type 2 diabetes mellitus (T2DM) is associated with poor bone health, including osteoporosis (OP) and osteopenia. The ZJU index, a novel calculation that integrates fasting plasma glucose (FPG), body mass index (BMI), triglyceride (TG), and alanine aminotransferase (ALT) to aspartate aminotransferase (AST) ratio, is strongly associated with glucolipid metabolism and insulin resistance (IR). In this study, we explored the association of ZJU with bone mineral density (BMD) and OP/osteopenia, and investigated the predictive effect of ZJU on OP/osteopenia in patients with T2DM. Methods: This cross-sectional study included 496 patients with T2DM aged>50 years. The clinical data were collected and the BMD of femoral neck (FN), left hip (LH), and lumbar spine (LS) were measured. The association between BMDs and ZJU levels was investigated by adjusting for covariates utilizing multiple linear regression analyses. Multivariable logistic regression was constructed to identify independent factors of OP and osteopenia, and receiver operating characteristic (ROC) curves were used to display the diagnostic performance according to the area under the ROC curve (AUC). Results: OP and osteopenia patients showed significantly higher ZJU levels than those with normal BMD in T2DM (39.387 ± 3.558, 38.112 ± 2.552 vs 35.192 ± 2.600, p < 0.001). Spearman's correlation analysis showed that ZJU was significantly negatively correlated with the BMD of FN (r = -0.39, p < 0.001), LH (r = -0.35, p < 0.001), and LS (r = -0.32, p < 0.001). The multiple linear regression indicated a negative association between ZJU and BMD of FN (β = -0.006, p = 0.009), LS (β = -0.155, p = 0.011) after adjusted for covariates. Meanwhile, the results of logistic regression revealed that the ZJU was a contributing factor to osteopenia and OP risk in T2DM individuals aged>50 years (OR 1.446, 95 % CI: 1.087-1.923, p = 0.011; OR 1.878, 95 % CI: 1.218-3.715, p = 0.039, respectively). ZJU provided the AUC value of 0.695 and 0.716 on osteopenia and OP in T2DM, respectively. Conclusions: A high ZJU index was significantly associated with an increasing risk of osteopenia and OP. The ZJU is expected to be a potential index for detecting decreased BMDs in middle-aged and elderly T2DM patients. Early intervention in T2DM patients with increased ZJU may further reduce the incidence of osteopenia and OP, in addition to focusing on independent biomarker in clinical practice.