The urinary β microglobulin-creatinine ratio is inversely associated with lumbar spine bone mineral density in the elderly Chinese males.

Unlabelled: Renal tubule cells play a pivotal role in maintaining bone homeostasis. Hence, renal tubular function may be associated with bone mineral density. Our study found that urinary β microglobulin-creatinine ratio (UBCR) levels correlated negatively with lumbar spine bone mineral density (BMD) and T and Z values, and may be a marker for osteoporosis in Chinese elderly male adults.

Purpose: To study the association of UBCR levels with BMD and the predictive value of UBCR for osteoporosis in elderly Chinese male adults.

Methods: A cross-sectional study of 149 (65 to 85 years, 69.7 ± 4.6) Chinese male adults who underwent health checkups in Huadong Hospital in Shanghai China was conducted. BMD was measured by dual-energy X-ray absorptiometry. The clinical variables and BMD of the participants in the low UBCR group (B1, UBCR < 300 μg/g) and the high UBCR group (B2, UBCR ≥ 300 μg/g) were compared. Associations between UBCR with clinical variables and BMD were analyzed by Pearson's correlation coefficient and multiple regression analysis. BMD and T and Z values were compared between the B1 and B2 groups. The odds ratios (ORs) for dose-dependent increases in osteoporosis between B1 and B2 were analyzed by binary logistic regression analysis. The area under the receiver operating characteristic (ROC) curve was used to analyze the capacity of UBCR to predict osteoporosis.

Results: UBCR was significantly higher in the osteoporosis group. After adjusting for multiple confounders, UBCR levels correlated negatively with BMD and T and Z values of the lumbar spine. Lumbar spine BMD and T and Z values were significantly lower in the B2 UBCR group than in the B1 UBCR group. Compared with the B1 participants, the ORs for "osteoporosis" were 12.401 times higher in B2 participants (P = 0.005) by binary logistic regression analysis after adjusting for potential confounders. The UBCR index (cutoff = 362.48 μg/g) had a sensitivity of 78.6% and a specificity of 68.7% for identifying osteoporosis, with an area under the ROC curve of 0.760.

Conclusions: These results suggest that UBCR levels correlate negatively with lumbar spine BMD and T and Z values and may serve as a marker for osteoporosis in Chinese elderly male adults.