The relationship between microvascular complications and vitamin D deficiency in type 2 diabetes mellitus

Abstract

BackgroundVitamin D deficiency is reported as a possible risk factor for the development of diabetes in several epidemiologic studies. In this study, we investigated the frequency of 25-OH vitamin D deficiency in type 2 diabetes mellitus and the relationship between 25-OH vitamin D deficiency and the prevalence of microvascular complications.MethodsIn this retrospective study, we evaluated the medical records of 557 patients with type 2 diabetes admitted to the Endocrinology Outpatient Clinic from January to March 2010 and 112 healthy controls randomly selected from individuals admitted to the hospital for a check-up and who had a laboratory result for serum 25-OH vitamin D concentrations at screening. The levels of 25-OH vitamin D in patients with type 2 diabetes and the relationship between 25-OH vitamin D deficiency and microvascular complications were investigated.ResultsNo significant difference in serum 25-OH vitamin D concentrations was observed between the diabetic and control groups. No correlation was observed between HbA1C and serum 25-OH vitamin D levels. Serum 25-OH vitamin D levels were lower in diabetic patients with nephropathy, and patients not using any medication, i.e., those treated with dietary changes alone, had a higher prevalence of nephropathy.ConclusionVitamin D deficiency is more common in diabetic patients with nephropathy. When microvascular complications were evaluated, vitamin D levels were found to be lower in patients in whom these complications were more severe. Vitamin D deficiency is therefore associated with microvascular complications in diabetic patients.

Adequate vitamin D status is associated with the reduced odds of prevalent diabetic retinopathy in African Americans and Caucasians

“…A number of studies have compared 25(OH)D concentrations between groups of individuals with and without diabetic retinopathy in case–control designs [3, 11, 13, 17, 22] with a protective association of 25(OH)D on prevalent retinopathy found in three studies [3, 11, 13]. The majority of other studies consist of cross-sectional designs recruiting participants from clinical settings [5, 6, 9, 10, 12, 14, 15, 19, 21, 23] with half of these studies supporting a protective association of vitamin D with retinopathy [5, 6, 9, 10, 12].…”

Vitamin D and retinal microvascular damage

“…[11] In view of these observations, we hypothesize that vitamin D could be linked to CVD through the presence of a microvascular component. Studies investigating the link between vitamin D and indices of microvascular disease have shown that vitamin D deficiency was associated with poor coronary microcirculation, [12] endothelial dysfunction, [13] nephropathy, [14] and with markers of cerebral small-vessel disease. [15] Although these studies suggest a microvascular component in the link of vitamin D with CVD, no study has investigated the direct relation of vitamin D with markers of microvascular damage in humans.…”

Diabetic peripheral neuropathy: the potential role of vitamin D deficiency

“…On the other hand, Tahrani and colleagues [19] and Usluogullari and colleagues [20] found no difference in the prevalence of vitamin D deficiency between diabetic peripheral neuropathy patients and controls. The contradiction between such results and our findings can be explained by, first, using different methods for diagnosis of peripheral neuropathy (they only used monofilament and vibration) and, second, neurophysiological tests had not been done.…”

“…In this study, there was no significant relation between the level of HbA1c and serum vitamin D level. Similarly, Olt [30] and Usluogullari and colleagues [20] failed to detect a relationship between HbA 1c and serum 25-OH vitamin D levels and stated that HbA1C levels were similar across groups with different 25-OH vitamin D concentrations.…”