What proportion of cancer deaths in the contemporary United States is attributable to cigarette smoking?

PURPOSE: The proportion of cancer deaths in the contemporary United States caused by cigarette smoking (the population attributable fraction PAF) is not well documented. METHODS: The PAF of all cancer deaths due to active cigarette smoking among adults 35 years and older in the United States in 2010 was calculated using age- and sex-specific smoking prevalence from the National Health Interview Survey (NHIS) and age- and sex-specific relative risks from the Cancer Prevention Study-II (for ages 35-54 years) and from the Pooled Contemporary Cohort data set (for ages 55 years and older). RESULTS: The PAF for active cigarette smoking was 28.7% when estimated conservatively, including only deaths from the 12 cancers currently formally established as caused by smoking by the US Surgeon General. The PAF was 31.7% when estimated more comprehensively, including excess deaths from all cancers. These estimates do not include additional potential cancer deaths from environmental tobacco smoke or other type of tobacco use such as cigars, pipes, or smokeless tobacco. CONCLUSIONS: Cigarette smoking causes a large proportion of cancer deaths in the contemporary United States. Reducing smoking prevalence as rapidly as possible should be a top priority for the US public health efforts to prevent cancer deaths.