Endocrine Abstracts

Introduction: Low levels of vitamin D are commonly found in people with type 1 diabetes and recently studies found that vitamin D deficiency (VDD) contributes to the risk of developing diabetic microvascular complications. The aim was to determine the relationship between microvascular complications of diabetes and 25-hydroxyvitamin D (25(OH)D) levels in type 1 diabetic patients.

Methods: A total of 143 adults (60 male and 83 female) with type 1 diabetes were enrolled in the study. 25(OH)D level (VD) was measured from October untill April. Patients with GFR<30 ml/min and with end stage renal disease were excluded from the study.

Results: Thirty-six (25.2%) type 1 diabetic patients had VDD – VD concentration was <25 pmol/l and 107 (74.8%) – had no VD deficiency (NVDD) – VD was >25 pmol/l. Age, sex,duration of diabetes, HbA1c, BMI, lipid profile, eGFR, use of alcohol, diabetic retinopathy – were no different (P>0.05) comparing between groups of VDD (the mean of VD 19.9±3.64 pmol/l) and NVDD (the mean of VD 42.3±13.73 pmol/l). There were more current smokers (38.9–19.0%, P=0.05), patients with GFR 30–59 ml/min (13.9–1.9%, P=0.016) and macroalbuminuria >300 mg/24 h (19.8–2.8%, P=0.05) in VDD group. VDD was more frequent in patients with multiple microvascular complications (VDD 80%, NVDD 41.9%) than in those without any complications (VDD 20%, NVDD 58.1%) (P=0.005) and in those with diabetic polyneuropathy (VDD 86.1%, NVDD 68.3%), that in patients without complications (VDD 13.9%, NVDD 31.7%) (P=0.038). Diabetic nephropathy was associated with VDD (VDD 47.2%, NVDD 22.4%) compared to patients with no renal complications (VDD 52.8%; NVDD 77.6%) (P=0.004). Binary logistic regression analysis revealed that the odds ratio (OR) for diabetic nephropathy independently increases linearly with VDD (OR=3.43; 95% CI 1.47–7.96, P=0.004).

Conclusion: Vitamin D deficiency was more common in type 1 diabetic patients with multiple microvascular complications and especially in those with diabetic nephropathy.