Vitamin D is Glucoprotective in Aging Males but Not Females

Type 2 diabetes is strongly linked to vitamin D deficiency in older adults. However, there is a discrepancy between clinical trials in adults on the efficacy of vitamin D treatment in prediabetes and diabetes. In addition, human data indicates there may be sexual dimorphism in the effect of vitamin D deficiency on dysglycemia that is more pronounced in men. These incongruities may be due to our limited understanding of the underlying mechanisms of vitamin D in glucose homeostasis among its vast target tissues across the body. Furthermore, vitamin D deficiency is diagnosed by low levels of a storage form of vitamin D, which may not be an accurate indicator of vitamin D status in these individuals. Thus, measuring expression levels of vitamin D receptor (VDR)-target genes across tissues involved in glucose regulation and vitamin D pathways may be a more promising marker of vitamin D status. Here we describe the sex-specific physiological effects of vitamin D supplementation in an aged, non-obese mouse model on glucose homeostasis and tissue-specific gene regulation.