SMOKING

Theory:

Some studies have suggested smoking increases the risk of breast cancer, although the link remains controversial. Scientists are now looking at the possibility that secondhand (or passive) smoke could increase your risk.

Both mainstream and secondhand smoke contain chemicals that, in high concentrations, cause breast cancer in rodents.

Certainly, chemicals in tobacco smoke can reach breast tissue and have been found in breast milk. A report from the California Environmental Protection Agency in 2005 concluded that the evidence about secondhand smoke and breast cancer is ‘consistent with a causal association’ in younger, mainly pre-menopausal women.

The theory is that much damage can be caused by exposure during childhood and puberty.

The 2006 U.S. Surgeon General’s report, The Health Consequences Of Involuntary Exposure To Tobacco Smoke, concluded that there is ‘suggestive but not sufficient’ evidence of a link with secondhand smoke.

Expert Comment:

It’s still not clear if smoking causes breast cancer. But we do know that the chemicals in cigarette smoke can cause at least a dozen different types of cancer around the body, so there’s still every reason to try to be a non-smoker and avoid passive smoke when you can.

Evidence for Link: STRONG