• Second hand
• smoking
• rules
• breast
• cancer
• premenopausal
• environmental tobacco smoke
• harm reduction
• smoking caused disease

Some review panels have concluded that second-hand tobacco smoke (SHS) causes breast cancer in premenopausal women. The California Environmental Protection Agency's Office of Environmental Health Hazard Assessment did a meta-analysis in 2005 of 19 studies on breast cancer and SHS exposure and concluded that regular exposure to SHS is ‘causally related to breast cancer diagnosed in younger, primarily premenopausal women.’ The meta-analysis, using a weight-of-evidence approach and specific criteria to deal with methodological issues common in the epidemiologic literature, yielded a combined OR of 1.68 (95% CI 1.31 to 2.15) for the 14 studies with analyses that included younger, primarily premenopausal women.1

In spite of such reviews, a firm agreement on the causal nature of an association between SHS and breast cancer remains elusive. In 2006, the Surgeon General's Report examined the same issue and concluded that the evidence was ‘suggestive but not sufficient’ to infer causality. They found a pooled risk estimate of 1.45 (1.04 to 2.01).2 While more well-designed longitudinal studies with adequate exposure assessment are certainly to come and add to those already in the literature, we …