October 2023 - The Sister Study, one of the institute’s largest and longest ongoing studies, examining the environmental and genetic influences on breast cancer in women with a family history of the disease, celebrated its 20th anniversary in October 2023. 

The Sister Study was initiated in response to community concerns about rising rates of breast cancer in the United States during the 1980s and 1990s. NIEHS launched the study and enrolled its first participant in the fall of 2003. By the spring of 2009 the study surpassed its goal of 50,000 participants. 

The study has discovered many of the factors that may contribute to a woman developing breast cancer, including air pollution, trauma and psychosocial stress, dietary factors, permanent hair dye and chemical hair straighteners, some ingredients in personal care products, and obesity.

Tags: breast cancer