Relationship Of Serum 25-hydroxyvitamin D₃ With Carotid Intima-media Thickness And Atherosclerotic Plaque In Type 2 Diabetic Patients

Background:At present,the relationship between vitamin D and non-skeletal diseases is increasingly appreciated.Some studies have shown that vitamin D is closely related to the occurrence and development of type 2 diabetes mellitus（T2DM）and complications.Macroangiopathy is a major chronic complication in diabetic patients and a leading cause of death in patients with T2 DM.A large number of studies have demonstrated that carotid intima-media thickness（IMT）can be used as a reliable predictor of diabetic macroangiopathy.Currently,there is little research about the correlation between vitamin D levels and carotid IMT in patients with T2 DM,and there is no definite conclusion.Object:To investigate the relationship between serum 25-hydroxyvitamin D₃ [25-（OH）D₃] concentrations and carotid IMT as well as carotid atherosclerotic plaque in patients with T2 DM.Method:A total of 314 patients with T2 DM were enrolled in this study.The general clinical data and laboratory examinations of all subjects were recorded,such as gender,age,diabetes duration,blood pressure,smoking history,hypertension history,hemoglobin A1c（HbA1c）,triglyceride（TG）,low density lipoprotein cholesterol（LDL-C）,high density lipoprotein cholesterol（HDL-C）,total cholesterol（TC）,serum calcium,fasting blood glucose（FBG）and other biochemical parameters.Serum 25-（OH）D₃,parathyroid hormone（PTH）and osteocalcin（OCN）levels were measured using an electro-chemiluminescence immuno-assay.Color Doppler ultrasound was used to measure carotid IMT and carotid atherosclerotic plaques.Patients were divided into four quartile groups according to the serum 25-（OH）D₃ concentrations: group Q1（<8.9ng/mL,71 cases）;group Q2 [（8.9-13.9）ng/mL,85 cases];group Q3 [（13.9-18.1）ng/mL,77 cases];group Q4（≥18.1ng/mL,81 cases）.Data were analyzed using SPSS 21.0 statistical software,including independent samples t-test,single factor analysis of variance（one-way ANOVA）,chi-square test,Pearson correlation analysis,Spearman correlation analysis,linear regression analysis and Logistic regression analysis.P<0.05 was considered statistically significant.Results:（1）.There were statistical differences in HbA1 c,LDL-C,PTH and serum calcium levels among the four groups（P<0.05）.From group Q1 to group Q4,the levels of HbA1 c,LDL-C and PTH gradually decreased,and the serum calcium levels increased.In addition,compared with group Q1,the systolic blood pressure in group Q3 was lower,the diabetes duration in group Q3 and group Q4 was shorter,and the HDL-C in group Q2 was higher（P<0.05）.（2）.There were statistical differences in carotid IMT and the prevalence of carotid atherosclerotic plaque among the four groups（P<0.05）.Carotid IMT in group Q1 [（1.23±0.40）mm] and group Q2 [（1.19±0.31）mm] was higher than that in group Q3 [（1.06±0.22）mm] and group Q4 [（0.93±0.17）mm]（P<0.05）,the carotid IMT in group Q3 was higher than that in group Q4（P<0.05）.The prevalence of carotid atherosclerotic plaque in group Q1（40 cases,56.34%）,group Q2（58 cases,68.24%）and group Q3（48 cases,62.34%）was higher than that in group Q4（32 cases,39.51%）（P<0.05）.（3）.Patients were divided into plaque group and non plaque group according to whether the patients had carotid atherosclerotic plaque.Compared with non plaque group,patients in plaque group were older,had a longer diabetes duration,higher HbA1 c,LDL-C and proportion of patients with hypertension（P<0.05）.But serum 25-（OH）D₃ concentrations were lower in the plaque group [178 cases,（13.4±5.8）ng/mL] compared with the non plaque group [136 cases,（15.7±8.0）ng/mL]（P<0.05）.（4）.Correlation analyses showed that carotid IMT was positively correlated with age,diabetes duration,systolic blood pressure,HbA1 c,LDL-C,smoking history and hypertension history,but negatively correlated with the levels of serum calcium and 25-（OH）D₃（P<0.05）.Multiple linear stepwise regression analysis showed that serum 25-（OH）D₃ concentrations were independently associated with carotid IMT（β=-0.009,P<0.05）.（5）.Logistic regression analysis showed that age,diabetes duration,hypertension history,HbA1 c,LDL-C were risk factors for the occurrence of carotid plaque（P<0.05）,but 25-（OH）D₃ could inhibit the occurrence of carotid plaque（OR=0.95;95%CI 0.92⁰.98,P<0.05）.Conclusion:Low vitamin D status may contribute to the incidence of carotid atherosclerosis in type 2 diabetic patients.