MIAMI -- African-American women had lower vitamin D levels than white women, and vitamin D deficiency was associated with a greater likelihood for aggressive breast cancer, according to data presented at the Third AACR Conference on the Science of Cancer Health Disparities.
"We know that darker skin pigmentation acts somewhat as a block to producing vitamin D when exposed to sunlight, which is the primary source of vitamin D in most people," said Susan Steck, Ph.D., M.P.H., associate professor of epidemiology at the University of South Carolina.
Steck and colleagues observed 107 women who were all diagnosed with breast cancer in the previous five years. Sixty of these women were African-American, while the remaining 47 were white.
All women donated a blood sample, and vitamin D status was determined using circulating 25 hydroxyvitamin D levels as a marker. The mean serum concentration of vitamin D was 29.8 ng/ml in white women and 19.3 ng/ml in African-American women.
Researchers defined vitamin D deficiency as a serum concentration less than 20 ng/ml, and found this to be the case in 60 percent of African-American women compared with 15 percent of white women. Serum levels were lowest among patients with triple-negative breast cancer, and aggressive disease was eight times more likely among patients with vitamin D deficiency.
Steck said the findings of this study provide a foundation for a possible prevention strategy, but further research would be required.
The study was funded by grants from the National Cancer Institute.
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The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, the AACR is the world's oldest and largest professional organization dedicated to advancing cancer research. The membership includes 32,000 basic, translational and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 90 other countries. The AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants, research fellowships and career development awards. The AACR Annual Meeting attracts more than 18,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment and patient care. The AACR publishes six major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; Cancer Epidemiology, Biomarkers & Prevention; and Cancer Prevention Research. The AACR also publishes CR, a magazine for cancer survivors and their families, patient advocates, physicians and scientists, providing a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship and advocacy.