Summary: Since darker skin pigmentation and aging are known factors influencing the body's ability to synthesis adequate amounts of Vitamin D, we hypothesize that: 1) the usual sun exposure in the southern United States may not be sufficient to maintain adequate vitamin D levels in elderly African American women, 2) recommended supplementation of Vitamin D 400 IU/d may not be adequate to prevent Vitamin D deficiency which in turn could lead to calcium deficiency and possibly sub-clinical hyperparathyroidism.