Does vitamin D deficiency contribute to increased rates of cardiovascular disease and type 2 diabetes in African Americans?

African Americans have higher rates of type 2 diabetes (T2D) and some forms of cardiovascular disease (CVD) than do European Americans. African Americans also have much higher rates of vitamin D deficiency. There is emerging evidence that vitamin D deficiency may be a risk factor for hypertension, T2D, and CVD, but the extent to which racial disparities in disease rates are explained by racial differences in vitamin D status is uncertain. Despite a large number of observational studies and a limited number of clinical trials that examined 25-hydroxyvitamin D [25(OH)D] concentrations as a potential determinant of CVD and T2D or its precursors, it remains uncertain whether improving vitamin D status would reduce risk of these conditions in the general US population or in African Americans specifically. However, if the associations reported from the observational studies are of the estimated magnitudes and causal, vitamin D supplementation could potentially have a strong preventive effect on some of these conditions and could reduce race-related disparities in their prevalence. Because of the low 25(OH)D concentrations of many, if not most, African Americans, and the low risk associated with vitamin D supplementation, it is important to obtain more definitive answers to these questions.