Lower levels of 25-hydroxyvitamin D₃are associated with a higher prevalence of microvascular complications in patients with type 2 diabetes

Abstract

ObjectiveLow levels of serum 25-hydroxyvitamin D [25(OH)D] are commonly found in type 2 diabetes. We examined whether there is an association between circulating 25(OH)D concentrations and the presence of microvascular complications in people with type 2 diabetes.Research design and methodsWe studied 715 outpatients with type 2 diabetes who regularly attended our clinic. Participants were evaluated for the presence of microvascular complications (namely retinopathy and/or nephropathy) by clinical evaluation, fundus examination, urine examination and biochemical tests. Serum 25(OH)D levels were also measured for each participant.ResultsHypovitaminosis D (ie, a serum 25(OH)D level <30 ng/mL) was found in 75.4%, while deficiency (ie, a 25(OH)D level <20 ng/mL) was found in 36.6% of these patients. Serum 25(OH)D levels decreased significantly in relation to the severity of either retinopathy or nephropathy or both. In multivariate logistic regression analysis, lower 25(OH)D levels were independently associated with the presence of microvascular complications (considered as a composite end point; OR 0.758; 95% CI 0.607 to 0.947, p=0.015). Notably, this association remained significant even after excluding those with an estimated glomerular filtration rate <60 mL/min/1.73 m2.ConclusionsWe found an inverse and independent relationship between circulating 25(OH)D levels and the prevalence of microvascular complications in patients with type 2 diabetes. However, vitamin D may be simply a marker and causality cannot be implied from our cross-sectional study. Whether vitamin D supplementation in patients with type 2 diabetes may have beneficial effects on the risk of microvascular complications remains to be investigated.

Association of Vitamin D and Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus

“…Inadequately controlled DM precipitates various long-term microvascular (blindness, n e p h r o p a t h y, a n d n e u r o p a t h y ) a n d macrovascular (cardiovascular and stroke) complications (1,2), which forms the leading cause of morbidity and mortality in patients of VDD has been associated with increased risk of chronic diseases, such as cancer, T2DM, cardiovascular disease, and autoimmune diseases including T1DM and multiple sclerosis, as evident from epidemiologic studies (1,8,18). N u t r i t i o n a l s t a t u s , p a r t i c u l a r l y micronutrients, might influence the risk for DR by affecting the biochemical mechanisms underlying DR (1,3).…”

“…Findings from some recent studies show a significant inverse association between 25-hydroxyvitamin D [25 (OH)D] levels and the prevalence of diabetic microangiopathy, thus suggesting that VD and microvascular complications are strictly interrelated. Nonetheless, whether lower levels of VD are the cause or result of the microvascular complications are currently unknown (2). Moreover, the possible role of vitamins in the pathogenesis of diabetic complications is of much interest (8).…”

Association of serum vitamin D and parathormone levels in patients of type 2 diabetes mellitus with diabetic retinopathy

“…He et al (2014) and thus, conflicted with our study result. According to the study by Zoppini et al (2015), the multiple logistic regression analysis showed that there were significant association of high vitamin D with reduced risk of diabetic retinopathy and that of longer duration of diabetes with increased risk of diabetic retinopathy. The dissimilarities of these two study results with our study findings indicate that a multi-institutional large sample case-control study is needed to be conducted.…”

Associations between vitamin D status and diabetic complications in Chinese population with type 2 diabetes mellitus: a cross-sectional study

“…In addition to mediating bone metabolism by regulating calcium and phosphorus homeostasis, vitamin D also modulates cell proliferation, differentiation, apoptosis, immune function, inflammation response, as well as vascular and metabolic properties (e.g., insulin secretion and insulin sensitivity) [12][13][14]. In the past few years, the association between vitamin D deficiency (VDD) and other nonclassical outcomes besides skeletal disorders has drawn increasing attention, especially diabetes and diabetes-related complications [14][15][16][17]. Although the inverse association between vitamin D levels and risk of T2DM [18,19], DR [20], DKD [21], or DFU [22] among diverse populations has been reported, uncertainties still exist due to the discordant results [23,24].…”