A Study On Association Between Vitamin D Levels And Type1Diabetes Mellitus

Objective：The differences from the serum25(OH) D3levels was Contrasted among type1diabetes mellitus (T1DM), type2diabetes mellitus (T2DM) and the population withnormal glucose tolerance. The purpose is to explore the association between vitamin Dlevels and incidence of type1diabetes mellitus.Methods：Forty-four T1DM patients whose age distribution is (30.89±14.42) years old(including male twenty-four, female twenty) and forty-seven T2DM patients whose agedistribution is (47.68±9.65) years old (including male twenty-six, female twenty-one)were selected from the people who visited the endocrinology department of Yan’anuniversity hospital outpatient and ward in February2012-March2014, and all thepatients were treated first (course <1year). And, thirty-four cases with normal glucosetolerance whose age distribution is (40.06±9.54) years old (including fifteen male,female nineteen) who visited Yan’an university hospital for healthy check-up at the sametime section in the spring and winter were selected as the control group.Using thediagnosis and classification standard put forward by the WHO committee of experts in1999diagnose diabetes.And using the diagnosis standard put forward by theinternational diabetes immunology in2005diagnose the latent autoimmune diabetes ofadult A questionnaire was used to collect information such as outdoor sportssituation,situation of food rich in vitamin D intake, use of sunscreen, and vitamin D supplement. All participants were invited to attend a physical examination. Also, theyneed complete the laboratory examination,including islet autoantibodies fasting Cpeptide,2h postprandial C-peptide, Serum25(OH) D3level. And then, the body massindex (BMI) was calculated. The single factor analysis of variance or the Single factoranalysis of varianceafter transforming variable or multiple independent samplesnonparametric tests would be selected after F test and normality test in the continuousquantitative data. Disorderly classification variable data using cross contingency tablechi-square test. Orderly classification variable data using multiple independent samplesnonparametric tests. The comparison of two samples for quantitative data usingindependent sample T test. Pearson correlation analysis was used for investigating therelationship between two continuous variables after demonstrating that they are lineartrend by drawing a scatter diagram in the T1DM group. For all analysis, a p value lessthan0.05is considered to reach statistical significance.Results:1. The serum25(OH) D3is on average of13.60±5.57ng/ml (95%confidenceinterval,11.91-15.29) in patients with T1DM group which is lower than the group withnormal glucose tolerance which25(OH) D3is on average of24.37±6.38ng/ml (95%confidence interval,22.14-26.60). The difference is statistically significant (P <0.05).2. The serum25(OH) D3is on average of16.73±5.00ng/ml (95%confidenceinterval,15.26-18.20) in patients with T2DM group which is lower than the the groupwith normal glucose tolerance.The difference is statistically significant (P <0.05).3. The average of25(OH) D3level in patients with T1DM group is lower than theT2DM group. the difference is statistically significant (P <0.05).4. According to the gender, there is no statistical significance in the differences of25(OH) D3level between men and women in the three groups.5. The level of25(OH)D3in the three groups was assessed as“sufficiency”(≥30ng/ml),“insufficiency”(20ng/ml≤25(OH)D3<30ng/ml),or“deficiency”(<20ng/ml). T1DM group: the proportion respectively in each group:0%,18.2%,81.8%. T2DM group: the proportion in each group respectively,0%,25.5%,74.5%. Normalglucose tolerance group: the proportion in each group respectively:26.5%,38.2%,35.5%. The proportion of T1DM group is the highest in the deficient group.And there isstatistically significant difference among the three groups.6. The25(OH) D3status with the fasting c-peptide as well as2h postprandialC-peptide levels is significantly positively related in T1DM group.The25(OH) D3statuswith the fasting c-peptide is lowly positively related in T2DM group.But,there is nostatistical significance between the25(OH) D3status and2h postprandial C-peptidelevels in T2DM group（P＞0.05）.7. In T1DM group,the positive odds of the islet autoantibody in the people whose25(OH) D3level is of deficient is about2.68times from the people is not ofdeficient.The positive probability of the islet autoantibody in the people whose25(OH)D3level is of deficient is about1.89times from the people is not of deficient.Conclusions:Vitamin D may be mediated by immune mechanisms involved in the onset ofT1DM.The potential protective effect of vitamin D in the onset of T1DM is worth beingfurther discussed.