Smoking as a Primary Risk Factor

It has been known for almost 50 years that tobacco use can be linked to cancers of the lung and head and neck. Eighty-five percent of the cases of head and neck cancer found each year are associated with tobacco use. Long-term smoking that begins before age 30 also increases the risk for developing colorectal cancer. Smoking contributes to cancer development by causing mutations in genes, impairing lung function, and decreasing the effectiveness of the immune system. See the following for more information:

• A Report of the Surgeon General: How Tobacco Smoke Causes Disease: What It Means to You
• Lung Cancer Prevention