Objective:To investigate the correlation of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone(PTH)and bone turnover markers with the glomerular filtration rate(GFR)in elderly male patients with type 2 diabetes mellitus.Methods:The study included a total of 426 non-dialyzed male T2DM patients with a disease course of more than 10 years, of whom 206 aged 60-86 years(the elderly group, 69.8±5.7 years old)and 220 aged 40-59 years(the middle-aged group, 50.1±5.3 years old). According to the estimated GFR(eGFR)calculated using the CKD-EPI formula, patients in each group were divided into four subgroups: Group 1(at CKD1 stage), Group 2(at CKD2 stage), Group 3(at CKD3 stage)and Group 4(at CKD4/5 stage). Levels of 25(OH)D, parathyroid hormone(PTH), procollagen type 1 N-terminal propeptide(P1NP), and C-terminal telopeptide of type Ⅰ collagen(β-CTX)in each group were measured.Results:The median level of 25(OH)D was 17.10(11.30-21.60) μg/L in 426 patients, of whom 292(68.5%)showed vitamin D deficiency.The level of 25(OH)D decreased significantly in the elderly group compared with the middle-aged group(15.10 μg/L vs. 17.15 μg/L, Z=-2.165, P=0.030), while the proportions of patients with vitamin D deficiency were similar in the two groups(68.4% vs. 68.6%, χ2=0.002, P=0.966). With decreasing eGFR, the proportion of patients with vitamin D deficiency gradually increased in the elderly.In the elderly cases, compared with the Group 1 and Group 2, the level of 25(OH)D in Group 3 dropped significantly (10.85 μg/L vs. 16.80 μg/L, Z=-2.808, P=0.005; 10.85 μg/L vs. 15.60 μg/L, Z=-2.099, P=0.044), and Group 4 showed an even more pronounced decrease than Group 3(6.65 μg/L vs. 10.85 μg/L, Z=-1.956, P=0.048). The level of 25(OH)D decreased significantly in the middle-aged patients at the CKD4/5 stage.The levels of PTH and β-CTX were negatively correlated with the 25(OH)D level( r=-0.348 and -0.263, P<0.001), and the level of negative correlation was affected by eGFR. Conclusions:In non-dialysis elderly male patients with T2DM, PTH and bone turnover marker β-CTX levels are negatively correlated with the 25(OH)D level, and the negative correlations are affected by eGFR.