Vitamin D Deficiency Linked to Aggressive Breast Cancer

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.

Vitamin D status was determined in blood samples from 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.

Circulating 25 hydroxyvitamin D levels were used as a marker and vitamin D deficiency was defined as a serum concentration less than 20 ng/mL. The mean serum concentration of vitamin D was 29.8 ng/mL in white women and 19.3 ng/mL in African-American women. Vitamin D deficiency was found in 60% of African-American women compared with 15% 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.

Susan Steck, Ph.D., M.P.H., associate professor of epidemiology at the University of South Carolina, (Columbia, SC, USA), said, "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". The findings of this study provide a foundation for a possible prevention strategy, but further studies would be required. The results of the study were presented at the Third American Association of Cancer Research Conference on the Science of Cancer Health Disparities, held in Miami, Florida, USA, September 30 – October 3, 2010.

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