Breastfeeding for two or more years reduces a woman’s risk of developing breast cancer by 50 percent, according to a study conducted in China by a Yale researcher. Tongzhang Zheng, Sc.D., associate professor of epidemiology and public health, said he conducted the study in China because, unlike in Western nations, long-term breastfeeding is part of the Chinese culture. Zheng’s group found a 50 percent reduction in breast cancer risk among women who had breastfed for more than 24 months per child, compared to women who breastfed for less than 12 months. Studies in Western countries showing that breastfeeding does not play a significant role in reducing breast cancer risk might be explained by the fact that many women in the West breastfeed for weeks or months rather than years. The study was published in the Dec. 15 issue of American Journal of Epidemiology.