The Relationship Between Serum 25（OH）D₃ And Microvascular Complications In Type 2 Diabetes Mellitums

Objective: This study explored the association between serum 25（OH）D₃ and diabetic microangiopathy（DMAP）in type 2 diabetes mellitus（T2DM）patients.Methods: A total of 812 hospitalized T2 DM patients from January 2013 to July 2015 were recruited.Patients were diagnosed with type 2 diabetes according to 1999 WHO criteria.Participants were evaluated for the presence of diabetic microangiopathy（namely diabetic peripheral neuropathy,retinopathy and/or nephropathy）by using fundus oculi examination,electromyography detection,aurinalysis and other clinical and biochemical characteristics.371 cases had no DMAP.Single DMAP was present in 296 cases,while the combination of two or three was present in 145 cases.Serum25（OH）D₃ levels were measured with electrochemiluminescnce immunoassay for each participant.Vitamin D deficiency was defined as a serum 25（OH）D₃ level < 20ng/ml and vitamin D insufficiency as a serum 25（OH）D₃ level of 20-30 ng/ml,vitamin D sufficiency as a 25（OH）D₃ level ≥ 30 ng/ml.Clinical and biochemical characteristics including duration of diabetes,body mass index,blood pressure,lipid profiles,glycated hemoglobin A–1c,fasting C-peptide and uric microalbumin were collected.SPSS20.0 software was used for statistical analysis.Multivariate ordinal logistic regression analysis was used to analyze the related influencing factors of diabetic microangiopathy.A receiver operating characteristic（ROC）curve was employed to find the cut-off of 25（OH）D₃ to indicate the occurrence of single DMAP and composite DMAP.Regard P<0.05 as the difference was statistically significant.Results:1.Vitamin D deficiency was found in 67.5%,while vitamin D insufficiency was found in 24.8% of these patients.2.The mean levels of serum 25（OH）D₃ in composite DMAP group[（16.23 ±8.28）ng/ml] and single DMAP group[（16.95±6.97）ng/ml],were separately lower than the SDM group [（19.41±8.13）ng/ml],the difference was statistically significant.（t=4.205、3.976,all P<0.01）.The deficiency ratio of vitamin D in composite DMAP group was higher than that of single DMAP and SDM group （77.9% vs 74.3% vs 58.0%,χ² =25.659,P<0.01）.3.Compared to the single DMAP group and SDM group,the composite DMAP group was older,had longer duration,higher ACR,UA and lower e GFR,meanwhile it had worse control of blood pressure,blood glucose,the difference was statistically significant.（F=4.042、26.35、22.93、3.764、6.810,χ² =37.662,all P<0.05）.4.Multivariate ordinal logistic regression analysis showed that duration of diabetes,SBP,Hb A1 c,UA,ACR were independent risk factors for DMAP（OR>1,P<0.05）.The levels of serum 25（OH）D₃ and the risk of DMAP of T2 DM were negatively correlated（Est=-0.027,OR=0.947,95%CI:（0.954）-（0.994）,P=0.011）,with 25（OH）D₃ levels decreased,the risk of DMAP and composite DMAP elevated;5.ROC analysis indicated that serum 25（OH）D₃<17.22 ng/m L（AUC = 0.663,P <0.01）may suggested the occurrence of single DMAP,whereas serum 25（OH）D<15.08 ng/m L（AUC = 0.708,P < 0.01）may predicted the occurrence of composite DMAP.（both P<0.01）.Conclusion:1.Duration of diabetes,SBP,Hb A1 c,UA,ACR are independent risk factors for DMAP,serum 25（OH）D₃ may be a protective factor for DMAP of T2 DM,and low vitamin D levels are closely related with the prevalence of single DMAP and composite DMAP.2.Serum 25（OH）D₃ may be considered as an auxiliary serum maker to screen DMAP.The prevalence of composite DMAP may elevate nearly 2 times when 25（OH）D₃ <15.08 ng / ml.Objective: This study investigated the relationship between the levels of serum25（OH）D₃ and each stage of diabetic peripheral neuropathy（DPN）in patients with type 2 diabetes mellitus.Methods:Cases diagnosed as DKD 、 DR and composite diabetic microangiopathy were removed from 812 cases,while remained cases were divided into sub-clinical neuropathic group（SDPN）of 91 cases,clinical peripheral neuropathic group（CDPN）of 140 cases,simple diabetic group（SDM）of 371 cases,according to the results of electromyography detection and the existence of the symptoms and signs of neuropathy or not.Duration,blood pressure,body mass index,25（OH）D₃,glycosylated hemoglobin,blood glucose,blood lipids and other biochemical parameters were collected.Multivariate ordinal logistic regression analysis was used to analyze the related factors of peripheral neuropathy.A receiver operating characteristic（ROC）curve was employed to find the cut-off of 25（OH）D₃ to indicate the occurrence of each stage of peripheral neuropathy.Regard P< 0.05 as the difference was statistically significant.Results:1.Among three groups,the difference of the levels of mean serum 25（OH）D₃ was statistically significant.The mean level of serum 25（OH）D₃ in the CDPN group（15.7±5.63）ng/ml was lower than SDPN group（17.31±6.37）ng/ml and the SDM group[（19.41±8.13）ng/ml,P<0.01],the deficiency ratio of vitamin D in CDPN was higher than that of SDPN and SDM group（84.3% vs 73.6% vs58.0%,χ² =35.94,P<0.01）.2.Multivariate ordinal multivariate Logistic regression analysis showed that the factors associated with each stage of DPN were duration of diabetes,SBP,25（OH）D₃ deficiency and Hb A1c（mean P<0.05）.3.Multivariate ordinal logistic regression analysis showed that 25（OH）D₃deficiency was an independent risk factors for DPN in T2DM（OR=4.453,95%CI （1.635）-（12.128）,P=0.003）.With the levels of 25（OH）D₃ reduced,the clinical symptoms and signs of DPN were more and more obvious.4.ROC curve analysis suggested that when the serum 25（OH）D₃< 17.49 ng/ml may suggested the occurrence of SDPN,and < 15.87 ng/ml may for the risk of CDPN.Conclusion:1.Duration of diabetes、systolic pressure and glycated hemoglobin and serum 25（OH）D₃ deficiency is independent risk factors for DPN,and low vitamin D levels are closely related with the prevalence of SDPN and CDPN.2.Serum 25（OH）D₃ may be considered as an auxiliary serum maker to screen SDPN in early stages,the prevalence of SDPN may elevate nearly 3 times when25（OH）D₃ <17.49 ng / ml.