According to a new study, Vitamin D deficiency is highly prevalent in patients with Type 2 diabetes and may be associated with poor blood sugar control..
The results are being presented at The Endocrine Society's 92nd Annual Meeting in San Diego.
"This finding supports an active role of vitamin D in the development of Type 2 diabetes," said study co-author Esther Krug, MD, an assistant professor of medicine at The Johns Hopkins University School of Medicine and an endocrinologist at Sinai Hospital, Baltimore.
Krug and her colleagues reviewed the medical charts of 124 patients with Type 2 diabetes who came to an endocrine outpatient clinic for specialty care from 2003 to 2008. Patients' age ranged from 36 to 89 years. All patients had a single measurement of their serum 25-hydroxyvitamin D levels as part of their evaluation at the clinic. The researchers divided the patients into quartiles based on vitamin D level.
Despite receiving regular primary care visits before referral to the endocrine clinic, 91 percent of patients had either vitamin D deficiency (defined as a level below 15 nanograms per deciliter, or ng/dL) or insufficiency (15 to 31 ng/dL), the authors reported. Only about 6 percent of patients were taking vitamin D supplements at their first visit.
Additionally, the investigators found an inverse relationship between the patients' blood levels of vitamin D and their hemoglobin A1c value, a measure of blood sugar control over the past several months. Lower vitamin D levels were discovered in patients with higher average blood sugars as measured by HbA1c, Krug said. Compared with whites, blacks had a higher average A1c and lower average vitamin D level.
"Since primary care providers diagnose and treat most patients with Type 2 diabetes, screening and vitamin D supplementation as part of routine primary care may improve health outcomes of this highly prevalent condition," she said.

Scientists from the Institute of Diabetes Research (IDF) and the Helmholtz Zentrum München, a member of the German Center for Diabetes Research (DZD), as well as from the Diabetes Research Group at the Technische Universität München (TUM) examined whether a vitamin D deficiency occurs during an early stage of type 1 diabetes, defined by the presence of multiple diabetes-specific islet autoantibodies. Furthermore they also determined whether vitamin D deficiency influences the progression to type 1 diabetes in children with multiple islet autoantibodies.
Vitamin D deficiency already exists in prediabetes
Children who had not yet developed clinical type 1 diabetes but who have multiple positive autoantibodies in their blood were found to have lower vitamin D levels than children without diabetes-specific autoantibodies. Interestingly, the differences in vitamin D levels were most prevalent in the summer months. These results were obtained from the BABYDIET, BABYDIAB, TEENDIAB and DIMELLI diabetes studies. The team of scientists headed by Jennifer Raab, Dr. Christiane Winkler and Professor Anette-Gabriele Ziegler compared the vitamin D measurements taken from 108 children who were tested positive for islet autoantibodies with 406 children without autoantibodies. Lower vitamin D levels were also found in 244 children who had recently been diagnosed with type 1 diabetes.
Progression of the disease remains unaffected
Prediabetes is defined as the presence of multiple islet autoantibodies. If and when the disease progresses, however, does not seem to be influenced by the vitamin D levels. Within the group of children with positive autoantibodies, a few children quickly developed type 1 diabetes -- however this was independent from their vitamin D levels.
Recommendation of vitamin D supplementation at an early stage of type 1 diabetes may be considered
"Vitamin D deficiency precedes the onset of type 1 diabetes. This may be a consequence of an immune response," Professor Ziegler says. "In the case of prediabetic children, we must therefore be mindful of the risk of vitamin D deficiency and consider recommending vitamin D supplementation at an early stage of type 1 diabetes."