Research On The Association Between Vitamin D And The Clinical Characteristics In Inpatients With Diabetes Mellitus

Objective The association between 25-hydroxyvitamin D(25OHD)and clinical characteristics in inpatients with diabetes mellitus was investigated including blood glucose parameters,blood pressure,blood lipid profile and the prevalence of diabetic chronic complications.Age may have an effect on the mode of the relationship between 25OHD and PTH.We are to investigate the effects of aging on the correlation between 25OHD and PTH in the inpatients of diabetes.Methods We retrospectively analyzed the clinical records of the inpatients department of endocrinology from Dec 2014 to Jun 2016(n=608).436 patients with completed record and meeting the inclusion criteria were enrolled.The information of Body Mass Index,Type of diabetes,systolic blood pressure(SBP),diastolic blood pressure(DBP)and the laboratory data including serum 25OHD,parathyroid hormone(PTH),Calcium,phosphorus,creatinine,Glycolated hemoglobinA1c(HbA1c),fasting blood glucose(FBG),insulin,blood lipid profile,urine albumin excretion rate(UAER)were examined.The data of diabetic nephropathy,diabetic retinopathy and the carotid artery atherosclerosis evaluated with Doppler ultrasonography.The clinical characteristics in different vitamin D status were compared and the associations between 25OHD and the clinical characteristics or the prevalence of diabetic chronic complications were analyzed with linear correlation model or Logistic regression.They were divided into group of age<65(n=298)and group of age ?65(n=138).The correlation of PTH and 25OHD was analyzed with partial correlation analysis and linear regression.Results The prevalence of vitamin D deficiency was high in the diabetic population,40.1%of the subjects suffered from a serum 25OHD lower than 10ng/mL.Using 25OHD level less than 10ng/mL as cut-off point,the patients were divided into vitamin D severe deficiency(Vit-SD)and vitamin D non-severe deficiency(Vit-NSD)group.Compared with the Vit-NSD group,the Vit-SD group(n=175)was with a higher HbAlc level(9.23 ± 2.25 vs 8.41 ± 1.86%,P<0.001),higher FBG(9.19 ±3.75 vs 8.50 ± 3.34 mmol/L,P=0.045),higher UAER(60.77 ± 80.42 vs 26.57 ±44.25ug/min,P<0.001),higher prevalence of diabetic nephropathy(43.43%vs 30.65%,P=0.005)and higher ratio of admission in Winter-Spring(73.08%vs 57.10%,P<0.001).According the quartile of 25OHD,the patients were subdivided into Q1-4 groups,Q4 with highest serum 25OHD has a lower HbAlc,2h-postprandial glucose,UAER ? prevalence of diabetic nephropathy compared with Ql-3.Association analyses showed that HbAlc and UAER have a significantly negative correlation with 250HD(r=-0.235,P=0.004)and(r=-0.228,P=0.005)respectively.Multiple stepwise linear regression revealed HbAlc had a significantly negative correlation with age(?=-0.249,P<0.001)and no correlation with PTH,serum calcium,serum phosphate and age.The Logistic regression revealed that in our inpatient diabetic population no relationship was found between 250HD or PTH with diabetic nephropathy,diabetic retinopathy and the carotid artery atherosclerosis evaluated with Doppler ultrasonography.Partial relationship adjusted with creatinine showed in the group of age<65,serum PTH had a significantly negative correlation with 250HD(r=-0.306,P=0.000)and in the group of age?65,serum PTH had a significantly negative correlation with calcium(r=-0.247,P=0.016),phosphorus(r=-0.289,P=0.026)and no correlation with 250HD or age.Linear regression revealed serum PTH decreased with the increase of 250HD in the group of age<65 and no such effect in the group of age?65.Conclusion Patients with diabetes in inpatient department have a high prevalence of vitamin D deficiency,especially in those having their 250HD checked in the Winter or Spring.Serum 250HD is negatively associated with HbAlc or UAER,independently with age,sex,serum creatinine,disease duration and BMI.In our research population,no correlation is found between 250HD and blood pressure or lipid profile.250HD is negatively associated with the prevalence of diabetic nephropathy stage IV and no correlation is found between 250HD and the prevalence of carotid artery atherosclerosis or diabetic retinopathy.The aging influences the correlation between serum PTH and 250HD.The further research of PTH,250HD and mineral metabolism will be helpful in clarifying whether we should define an age-dependent normal range of PTH and 250HD.