Vitamin D Deficiency in Elderly African American Women in Central Texas

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.

This study will enroll 60 African American women age 65 or older who do not have renal, hepatic or gastrointestinal disorders that could affect Vitamin D and calcium absorption and metabolism. Patients will have two scheduled office visits. Demographic data will be collected with attention to dietary intake of calcium and vitamin D, and the patient's customary degree of sun exposure. Ca, 25-hydroxyvitamin D, PTH and serum CTX (a bone resorption marker) are measured on enrollment day and repeated 6 weeks later. All patients not already taking 1000 mg Calcium with 400 IU of Vitamin D orally daily were given samples of this supplement to last for 6 weeks without making any change in diet or sun exposure recommendations. The study period will extend April to June - a time when there should be ample sunlight but it is not so hot as to stop the elderly from going outdoors. Statistical analysis will be performed as to the effect(s) of ethnic background, age, diet, and intensity of sun exposure as related to Ca, 25-hydroxyvitamin D, PTH and serum CTX.

Inclusion criteria

• Age 70 or older woman
• African American ethnicity
• Non-institutionalized

Exclusion criteria

• De-compensated hepatic insufficiency
• Renal insufficiency with GFR estimated to be < 30 ml/min
• Gastrointestinal disorders that might affect absorption such as known malabsorption, celiac sprue, short gut or blind loop syndrome.
• Institutionalized