Since the publication of the surgeon general’s seminal 1964 report on smoking, research has confirmed that smoking causes cancers of the esophagus, larynx, oral cavity and pharynx, stomach, pancreas, lung, cervix, kidney, and bladder and causes acute myeloid leukemia (IOM, 2007). It also causes a variety of other diseases, including stroke, atherosclerosis, cardiovascular disease, COPD, and such infectious diseases as influenza, and it increases the risk of infection (US Surgeon General, 2007). In short, a lifelong smoker has a 1-in-2 chance of dying prematurely from a complication of smoking. As a result of the 1964 report and later reports from the surgeon general and public-health campaigns, there has been a substantial decline in the use of tobacco in the US population. Smoking rates dropped from more than 42% before 1964 (CDC, 2009) to less than 20% today. Nevertheless, tobacco use continues to be the number one cause of preventable death in the United States and is a major cause of chronic disease, disability, and death in military veterans (IOM, 2007). This section briefly reviews long-term health consequences of smoking (see Table 2-4); for a detailed review, the reader is referred to the surgeon general’s recent reports on smoking and health (US Surgeon General, 2004, 2007).
Smoking is the greatest preventable cause of cancer and is responsible for 30% of cancer deaths (ACS, 2008). Lung cancer is the leading cause of cancer mortality in the United States; 90% of lung-cancer cases in men and 80% in women are attributable to smoking (US Surgeon General, 2004). The risk of lung cancer and other cancers is proportional to the number of cigarettes smoked per day and the duration of smoking (US Surgeon General, 2004). However, even quitting smoking at the age of 50 years can reduce the lifelong risk of lung cancer by half. Workplace exposure to asbestos, as may occur in military construction and maintenance workers and mechanics, synergistically increases the risk of lung cancer posed by smoking. Alcohol use also acts synergistically with smoking to cause oral laryngeal and esophageal cancer (see Table 2-6). Cervical cancer is more common in women who smoke. Smoking is responsible for 20–30% of leukemia cases in adults, including lymphoid and myeloid leukemia (CDC, 1989). Smoking was associated with an increase in risk of colorectal cancer in men and women in a meta-analysis of 36 studies (Kenfield et al., 2008). Exposure to such industrial solvents as benzene, with which military personnel may work, presumably adds to the effect of the benzene in tobacco smoke in causing leukemia (US Surgeon General, 2004).