['The effect of mild renal dysfunction on bone mineral density and fracture risk is uncertain.', 'We evaluated whether mild renal dysfunction would affect bone mineral density (BMD) and the risk of vertebral fractures (VFs) in 659 postmenopausal women.', 'Creatinine clearance (CCr) and the estimated glomerular filtration rate (eGFR) were calculated using the Cockcroft-Gault and the Modification of Diet in Renal Disease formulas, respectively. BMD was measured by dual-energy x-ray absorptiometry. Renal function was categorized by the criteria of the Kidney Disease Outcomes Quality Initiative Committee.', 'Comparison of fracture prevalence by chronic kidney disease stages revealed that the group of stage 3 or greater by eGFR had a significantly higher rate of VFs (45.3%) than stages 1 (23.8%) and 2 (25.3%) groups. In the stage 2 group, there were significant positive correlations between eGFR and BMD values at the femoral neck and radius as well as between CCr and BMD values at all sites. Moreover, postmenopausal women with VFs had lower eGFR and CCr than those without VFs in stage 2. When multivariable logistic regression analysis was performed with the presence of VFs as a dependent variable and CCr levels adjusted for years after menopause, smoking habit, alcohol intake, and lumbar spine BMD as an independent variable, CCr levels were identified as a factor associated with the presence of VFs in postmenopausal women with chronic kidney disease stage 2.'] Is mild renal dysfunction a risk factor for a decrease in bone mineral density and vertebral fractures in Japanese postmenopausal women?