Secondhand smoke tied to breast cancer
SAN FRANCISCO – Scientists at an influential California agency have concluded that secondhand smoke causes breast cancer, a finding that could have broad impact on cancer research and lead to even tougher anti-smoking regulations.
Although recent studies have linked smoking to breast cancer, no major public health group, including the American Cancer Society, Centers for Disease Control and Prevention and National Cancer Institute, has declared it a cause of the disease that kills 40,000 women annually in the United States.
In a state that already has the nation’s most restrictive smoking laws, the finding by scientists for the Air Resources Board could encourage a state ban in one of the last unregulated domains: vehicles carrying children. It could fuel workplace smoking prohibitions in more states. And it likely will refocus the scientific debate over the association between smoking and breast cancer.
A scientific review panel is expected to approve the report as early as Monday and forward it to the Air Resources Board, which has broad state authority to regulate air pollution. The board’s early efforts to regulate auto emissions set the standard across the country.
The report analyzes new data on the extent of Californians’ exposure to secondhand smoke and more than 1,000 studies of health effects from secondhand smoke.
The conclusion that secondhand smoke causes breast cancer, particularly in younger women, challenges conventional thinking because most studies have found no link between active smokers and breast cancer, much less secondhand smoke.
But California scientists based their conclusion on recent human studies that they determined had more careful assessments of exposure to tobacco smoke.
Overall, the report said women exposed to secondhand smoke have up to a 90 percent greater risk of breast cancer. Secondhand smoke kills as many as 67,700 people a year in the USA, the report says.
The report did not estimate the number of additional new breast cancer cases annually, and scientists did not calculate risk levels based on doses of secondhand smoke.