African-American women, vitamin D levels and aggressive breast cancer

Researchers have found that African-American women have lower vitamin D levels than white women, and vitamin D deficiency is associated with a greater likelihood for aggressive breast cancer. 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. Scientists 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% 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.