Association between serum 25-hydroxyvitamin D and glycated hemoglobin levels in type 2 diabetes patients with chronic kidney disease

Aims/Introduction Vitamin D is suggested to influence glucose homeostasis. An inverse relationship between serum 25-hydroxyvitamin D [25(OH)D] and glycemic control in non-chronic kidney disease (CKD) patients with type 2 diabetes (T2D) was reported. We aimed to examine this association among T2D patients with CKD. Materials and Methods 100 T2D participants with stage 3-4 CKD were recruited. Blood for HbA1c, serum 25(OH)D, renal, and lipid profiles were drawn at enrolment. Correlation and regression analyses were performed to assess the relationship of serum 25(OH)D, HbA1c, and other metabolic traits. Results 30%, 42%, and 28% of participants were in CKD stage 3A, 3B, and 4, respectively. It comprised 51% Malay, 24% Chinese, and 25% Indian. The mean (±standard deviation) age and body mass index (BMI) were 60.5 ± 9.0 years and 28.3 ± 5.9 kg/m2, whereas mean HbA1c and serum 25(OH)D were 7.9 ± 1.6% and 37.1 ± 22.2 nmol/L. HbA1c was negatively correlated with serum 25(OH)D (rs = -0.314, P = 0.002), whilst positively correlated with BMI (rs = 0.272, P = 0.006) and serum LDL-cholesterol (P = 0.006). There was a significant negative correlation between serum 25(OH)D and total daily dose of insulin prescribed (rs = -0.257, P = 0.042). Regression analyses indicated every 10 nmol/L decline in serum 25(OH)D was associated with a 0.2% increase in HbA1c. Conclusions Lower serum 25(OH)D was associated with poorer glycemic control and higher insulin use among multi-ethnic Asians with T2D and stage 3-4 CKD. This article is protected by copyright. All rights reserved.