Impact of oral 1,25-dihydroxy vitamin D (calcitriol) replacement therapy on coronary artery risk factors in type 2 diabetic patients.

BACKGROUND: Observational data suggest that low 25-hyroxyvitamin D is associated with cardiovascular disease (CVD) and its risk factors include diabetes, metabolic syndrome, insulin resistance, hypertension, microalbuminuria and inflammation. We examined the differences between risk factors of CVD before and after treatment with calcitriol in type 2 diabetic patients with vitamin D deficiency. METHODS: This study was a clinical trial consisting of 119 type 2 diabetic patients. Forty three patients had vitamin D insufficiency (25 OH D less than 30 ng/dl) who underwent calcitriol treatment with 0.5 microgram per day for 8 weeks. Blood pressure, fasting blood sugar (FBS), glycosylated hemoglobin (HbA1C), lipid profile, high sensitive C-reactive protein (HsCRP), Homocysteine and albumin to creatinine ratio were measured, before and after the treatment period. Then the two sets of results were compared with each other. RESULTS: Following treatment with calcitriol HbA1C, total cholesterol, low density lipoprotein(LDL), high density lipoprotein(HDL) and diastolic blood pressure decreased significantly (p = 0.01, 0.01, 0.04, 0.001 and 0.04 respectively) but the changes in other parameters were not significant. CONCLUSION: Replacement of vitamin D may have a beneficial effect on some of the risk factors of CVD in diabetic patients.

Association between Serum 25 (OH) Vitamin D Concentrations and Inflammatory Bowel Diseases (IBDs) Activity

Inflammatory bowel diseases (IBDs) are immune mediated diseases affecting the gastrointestinal tract. Several environmental factors in concert with genetic susceptibilities can trigger IBDs. Recently, one of the important environmental factors contributing to the development of autoimmune diseases is vitamin D (VitD) deficiency. Furthermore, some new evidence points to VitD deficiency and its receptor dysfunction as an underlying factor for the emergence experimental IBDs. The aim of the current study was to evaluate the correlation between serum 25(OH)D concentrations and IBD activity in patients with ulcerative colitis or Crohn’s disease. Sixty patients with confirmed diagnosis of IBD were recruited for a cross sectional study. Most of the identified confounders affecting serum VitD concentrations were excluded. Disease activity was assessed using validated questionnaires, including Truelove for Ulcerative Colitis and Crohn Disease Activity Index (CDAI) for Crohn disease. Serum 25(OH)D concentrations were determined by chemiluminescent assay. Serum 25(OH)D≤10 (ng/ml) was considered as VitD deficiency and 11≤25(OH)D<29(ng/ml) as VitD insufficiency. Mean serum 25(OH)D value was 13.1 ± 11.1(ng/ml) in IBD patients. Almost 95% of patients were vitamin D insufficient or deficient. Forty one percent of IBD patients had active disease. VitD deficiency was not associated with IBD activity (p=0.23). However, VitD deficiency was significantly associated with a history of IBD related intestinal surgery (p=0.001). In conclusion, this cross-sectional prospective study suggested that there is no association between vitamin D deficiency and disease activity in a relatively small number of IBD patients in a short period of time.

The effects of calcitriol on albuminuria in patients with type-2 diabetes mellitus.

The renin-angiotensin system has a major role in the development of diabetic nephropathy (DN). It is reported that vitamin D analogues are able to suppress renin excretion. Thus, this study was conducted to determine whether there is any correlation between albuminuria as a marker of DN with vitamin D levels in diabetic patients. Also, an assessment was made on the effects of vitamin D therapy on albuminuria in this group of patients. We conducted this cross-sectional study on 119 outpatients with type-2 diabetes. The serum levels of 25-hydroxy vitamin D [25 (OH) D] and the albumin to creatinine ratio were assessed in all the study patients. Patients with vitamin D deficiency/insufficiency received calcitriol therapy for eight weeks, following which the laboratory tests were repeated. The mean age of the study patients was 55.3 ± 11.2 years, 43 (36.13%) had vitamin D insufficiency [25 (OH) D <25 ng/mL] and 31 (26.1%) had vitamin D deficiency [25 (OH) D <15 ng/mL]. We found a significant correlation between 25 (OH) D levels and presence of microalbuminuria (P = 0.04) in patients with vitamin D deficiency. Therapy with calcitriol had a beneficial effect on the albumin excretion rate, although this change was not significant (P = 0.22). However, the effects of calcitriol on reduction of diastolic blood pressure (P = 0.004), glycosylated hemoglobin (P = 0.014) and levels of total cholesterol (P = 0.019), low-density lipoprotein (0.04) and high-density lipoprotein (P = 0.001) was significant. Our study suggests that vitamin D deficiency has a negative effect on albuminuria in diabetic patients, and its replacement may be associated with a beneficial effect on the risk factors of DN, such as hyperlipidemia and hypertension.