Recent studies may explain inconsistencies between previous results, say researchers, and a real risk may be emerging.

Summarizes the research findings on tobacco smoke as a cause of breast cancer.

Early studies treated secondhand smokers as if they were nonsmokers, which actually masked the evidence; later studies separated out the two, and found that both active and passive smoking are causes of breast cancer.

Summary of recent research based on data from 1994-1997.

Characterizes the risk and provides a bibliography of research establishing the risk.

Scientific article; meta-analysis of 11 studies estimates a 40% higher risk of breast cancer as a result of exposure to secondhand smoke.

Report on 1996 study: "the relative risk for breast cancer from passive smoke (primarily girls whose parent smoked or women whose spouse smoked) was 3.2! This makes passive smoking a more important risk factor than having a mother with breast cancer (2.1), or having an early first period (1.3), or having a late first pregnancy (1.4)."

Recent research shows an association between smoking and breast cancer.