Background: Low circulating levels of total vitamin D [25(OH)D] and 25(OH)D-3 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) D-2, 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) D-2 and 25(OH)D-3 and the prevalence of albuminuria, retinopathy and cardiovascular disease (CVD) in individuals with type 1 diabetes. Methods: We measured circulating 25(OH)D-2 and 25(OH)D-3 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)D-2 and 25(OH)D-3 with albuminuria, retinopathy and CVD were assessed with multiple logistic regression analyses adjusted for age, sex, season, BMI, smoking, HbA1c, 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)D-2 and 10 nmol/L higher 25(OH)D-3 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)D-2 and 25(OH)D-3 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)D-2 and 25(OH)D-3 and the development of microvascular complications and CVD in type 1 diabetes.
Engelen, L., Schalkwijk, C. G., Eussen, S. J. P. M., Scheijen, J. L. J. M., Soedamah-Muthu, S. S., Chaturvedi, N., Fuller, J. H., & Stehouwer, C. D. A. (2015). Low 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 levels are independently associated with macroalbuminuria, but not with retinopathy and macrovascular disease in type 1 diabetes: the EURODIAB prospective complications study. Cardiovascular Diabetology, 14, . https://doi.org/10.1186/s12933-015-0231-2