colon, stomach, cervix, and liver. Recent declines in the rates of lung cancer in the United States among men—first among those who are younger and then among those who are older successively over time—and among women ages 40 to 59 reflect past declines in the use of cigarettes (Wingo et al., 1999). The cessation of tobacco use reduces the excess risk of nearly all of these cancers over time. Obesity increases the risk of breast, endometrial, colorectal, kidney, and esophageal cancer. Regular physical activity lowers the risk of cancers of the colon and breast cancer, and, possibly, endometrial cancer as well. Regular alcohol intake increases the risk of cancers of the oropharynx, larynx, esophagus, breast, liver, colon, and rectum. Diet has been linked to several cancers, with the most consistent evidence linking the consumption of large amounts fruits and vegetables with a lower risk cancer.
Numerous researchers have also estimated that positive changes in these lifestyle factors can reduce a good proportion of the national cancer burden (see Chapter 2). Although the specific methods and the results of these analyses vary, they are all remarkably consistent in pointing to the potential benefits of reducing tobacco use, improving diet, increasing physical activity, maintaining a healthy body weight, keeping alcohol consumption at low to moderate levels, and getting screened regularly for cancer.