OBJECTIVETo evaluate the relationship between 25-hydroxy vitamin D [25(OH)D] and carotid artery intimal medial thickness (IMT) in type 2 diabetic (T2DM) patients.

METHODSSerum 25(OH)D and carotid IMT were measured in 300 T2DM patients. Patients were divided into four quartile groups according to the serum 25(OH)D levels (Q1: < 26.17 nmol/L, 74 cases; Q2: 26.17 - 32.75 nmol/L, 76 cases; Q3: 32.75 - 42.93 nmol/L, 78 cases; Q4 > 42.93 nmol/L, 72 cases).

RESULTSCarotid IMT, carotid artery plaque prevalence, duration of diabetes, HbA1c, CRP and PTH were significantly higher in subjects with low 25(OH)D compared subjects with high 25(OH)D (P < 0.05). Carotid artery IMT in Q1 and Q2 groups were significantly higher than that in Q4 group (1.03 ± 0.21 vs. 0.90 ± 0.20, 1.01 ± 0.26 vs. 0.90 ± 0.20, P < 0.05), was similar among Q1 and Q2 and Q3 groups. Prevalence of carotid atherosclerotic plaque in Q1 group (50.0%) was also significantly higher than in Q3 (29.5%, P < 0.05) and Q4 (16.7%, P < 0.05). Similarly, 25(OH)D concentration was significantly lower in patients with carotid plaque compared patients without carotid plaque [(28.31 ± 4.91) nmol/L vs. (36.31 ± 4.31) nmol/L, P < 0.01]. Pearson correlation analysis showed that carotid IMT was positively correlated with age, smoking, BMI, HbA1c, CRP, LDL-C, PTH/25(OH)D ratio (P < 0.05), and was negatively correlated with 25 (OH) D (r = -0.51, P < 0.01). Multivariate regression analysis showed that 25(OH)D concentration was an independent predictor of carotid IMT in this cohort (β = -0.39, P < 0.01).

CONCLUSIONSerum 25(OH)D concentration is negatively correlated with carotid IMT and low 25 (OH) D level is a risk factor for preclinical atherosclerosis in T2DM patients.