Low 25-Hydroxyvitamin D Linked to Macroalbuminuria in T1D

Abstract and Introduction

Abstract

Background: Low circulating levels of total vitamin D [25(OH)D] and 25(OH)D₃ have been associated with vascular complications in few studies on individuals with type 1 diabetes. However, these measures are affected by UV light exposure. Circulating 25(OH)D₂, however, solely represents dietary intake of vitamin D₂, but its association with complications of diabetes is currently unknown. We investigated the associations between 25(OH)D₂ and 25(OH)D₃ and the prevalence of albuminuria, retinopathy and cardiovascular disease (CVD) in individuals with type 1 diabetes.

Methods: We measured circulating 25(OH)D₂ and 25(OH)D₃ in 532 individuals (40 ± 10 years old, 51 % men) with type 1 diabetes who participated in the EURODIAB Prospective Complications Study. Cross-sectional associations of 25(OH)D₂ and 25(OH)D₃ with albuminuria, retinopathy and CVD were assessed with multiple logistic regression analyses adjusted for age, sex, season, BMI, smoking, HbA_1c, total-HDL-cholesterol-ratio, systolic blood pressure, antihypertensive medication, eGFR, physical activity, alcohol intake, albuminuria, retinopathy and CVD, as appropriate.

Results: Fully adjusted models revealed that 1 nmol/L higher 25(OH)D₂ and 10 nmol/L higher 25(OH)D₃ were associated with lower prevalence of macroalbuminuria with ORs (95 % CI) of 0.56 (0.43;0.74) and 0.82 (0.72;0.94), respectively. These vitamin D species were not independently associated with microalbuminuria, non-proliferative and proliferative retinopathy or CVD.

Conclusions: In individuals with type 1 diabetes, both higher 25(OH)D₂ and 25(OH)D₃ are associated with a lower prevalence of macroalbuminuria, but not of retinopathy and CVD. Prospective studies are needed to further examine the associations between 25(OH)D₂ and 25(OH)D₃ and the development of microvascular complications and CVD in type 1 diabetes.