Vitamin D deficiency among African-American women increases aggressive breast cancer:

[News]

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.

More... (http://www.news-medical.net/news/20101003/Vitamin-D-deficiency-among-African-American-women-increases-aggressive-breast-cancer-Study.aspx)