Association Of Serum25-hydroxyvitamin D3with Islet Function, Insulin Resistance, Peripheral Vascular Disease And Oxidative Stress In Elderly Patients With Type2Diabetes

Objective:1).To compare the differences of serum25-hydroxyvitaminD₃（25（OH）D₃）in elderly patients with type2diabetes to healthy controls.2).To study the relationship between the serum25-hydroxyvitamin D₃and isletbeta cell function, insulin resistance, and peripheral vascular lesions in elderlypatients with type2diabetes.3).To explore the relationship between theserum25（OH）D₃and oxidative stress in elderly patients with type2diabetes.Methods: Fifty-nine elderly patients with type2diabetes and49healthycontrols were enrolled into the study. Serum levels of fasting serum25（OH）D₃was measured in all subjects. Serum fasting serummalondialdehyde （MDA）, superoxide dismutase （SOD）, blood glucose,fasting insulin （FINS） and carotid intima-media thickness were measured inelderly patients with type2diabetes. The comparison of differences betweenserum25（OH）D₃in elderly patients with type2diabetes and healthy controlswas performed by using Student’s t test. The relationship between serum25（OH）D₃and MDA, SOD, carotid intima-media thickness, insulin resistanceand beta cell function were analyzed by using Pearson correlation analysis.To use respectively The multiple stepwise regression analysis was also usedto evaluate the risk factors for islet beta cell function and oxidative stress.Results:1). There were no significant difference in gender, age, bodymass index （BMI）, cholesterol （TC） and diastolic blood pressure （DBP）.However, systolic blood pressure （SBP）, glycerin three greases （TG）, low density lipoprotein cholesterol （LDL-C）, high density lipoprotein cholesterol（HDL-C）, FPG and glycosylated hemoglobin （HbA1c） were significantlydifferent between the two groups（p＜0.05or p＜0.01）.2). The level of serum25（OH）D₃was significantly lower in the elderlypatients with type2diabetes than that in the healthy controls （29.32±15.24nmol/L vs.43.17±17.15nmol/L, t=-4.442, p＜0.01）.3. Pearson correlation analysis showed that the serum25（OH）D₃wasnegatively correlated with MDA （r=-0.350, p＜0.01）, but positivelycorrelated with SOD （r=0.462, p＜0.01）. Multiple stepwise regressionanalysis showed that25（OH）D₃and FPG were independent influencingfactors for MDA （β=-0.301，p＜0.05andβ=0.308，p＜0.05）, respectively,25（OH）D₃and HDL-C were independent influencing factors for SOD（β=0.448，p＜0.01andβ=0.284，p＜0.05, respectively）.4. Pearson correlation analysis also showed that the serum25（OH）D₃was positively correlated with HOMA2-%B （r=0.400, p＜0.01）, but nocorrelation with HOMA2-IR and HOMA2-%S. Multiple stepwise regressionanalysis showed that25（OH）D₃and FPG were independent influencingfactors for HOMA2-%B （β=0.304， p＜0.01andβ=-0.607， p＜0.01,respectively）.5. In the elderly patients with type2diabetes, there was no significantcorrelation between serum25（OH）D₃and carotid intima-media thickness（r=-0.081, p=0.542）.Conclusions: From the results we can concluded that1). The level of serum25-hydroxyvitamin D₃was decreased in elderlypatients with type2. 2). There is a relationship between low levels of25-hydroxyvitamin D₃and islet beta cell dysfunction, but not insulin resistance.25-hydroxyvitaminD₃and FPG were independent influencing factors for HOMA2-%B.3). Low25-hydroxyvitamin D₃level may enhance oxidative stress levelsin elderly patients with type2diabetes.25-hydroxyvitamin D₃and FPG wereindependent influencing factors for MDA, and25-hydroxyvitamin D₃andHDL-C were independent influencing factors for SOD.4). There was no significant correlation with25-hydroxyvitamin D₃leveland peripheral vascular disease in elderly patients with type2diabetes.