Vitamin D Status and Incident Type 2 Diabetes

点击翻译按钮获取中文摘要

DESCRIPTION (provided by applicant): The incidence of type 2 diabetes mellitus is increasing at an alarming rate both nationally and worldwide with more than 1 million new cases per year diagnosed in the US alone. Although weight-loss has been shown to be successful in delaying diabetes, it is difficult to achieve and maintain long-term. Therefore, identification of weight-independent environmental and easily modified risk factors is urgently needed to prevent the increase in the incidence of type 2 diabetes. Vitamin D is a nutritional factor that has been suspected as a modifier of diabetes risk based on animal and human studies including our own preliminary observational data. However, there are critical gaps in our knowledge about the magnitude of the clinical effect of vitamin D on diabetes risk. Currently, this lack of data limits the usefulness of vitamin D as a feasible nutritional intervention for prevention of type 2 diabetes. The central hypothesis of the proposed study is that, vitamin D insufficiency is a risk factor for the development of type 2 diabetes. We plan to test our main hypothesis and accomplish the objectives of this application by pursuing an ancillary study to an ongoing observational study to assess the magnitude of the association between vitamin D status and risk of developing type 2 diabetes. The working hypothesis is that vitamin D status, as measured by serum 25OHD level, is inversely associated with type 2 diabetes risk. The association will be quantified in a nested case-control study design in healthy women in a large prospective cohort, the Nurses' Health Study (600 t2DM cases and 600 controls - matched by age and season of blood draw). We will adjust for potential diabetes confounders (demographic, medical and nutritional) that have been measured and we will also examine whether the association is modified by BMI or calcium intake.