For this reason, it is important to follow national trends data to monitor the reduction of these risk factors. This section focuses on national trends data from two major groups of risk factors: Behavioral and Environmental.

Behavioral Factors

Scientists estimate that as many as 50–75 percent of cancer deaths in the United States are caused by human behaviors such as smoking, physical inactivity, and poor dietary choices. The first part of the Prevention section describes trends in the following behaviors that can help to prevent cancer.

Tobacco Use

Smoking causes about 30 percent of all U.S. deaths from cancer. Avoiding tobacco use is the single most important step Americans can take to reduce the cancer burden in this country.

Diet

Maintaining a healthy weight and eating a moderate-fat diet and enough fruits and vegetables while limiting consumption of red meat and avoiding too much alcohol is also an important step in reducing cancer risk.

Physical Activity

Obesity and physical inactivity cause about 25–30 percent of several of the major cancers in the U.S., including colon, breast, endometrial, kidney, and esophageal cancers. Obesity is estimated to cause 14 percent of cancer deaths in men and 20 percent of cancer deaths in women.

Sun Protection

The number of new cases of melanoma skin cancer has increased between 1975 and 2004, with an estimated number of 60,000 new cases in 2007.

Environmental Factors

Certain chemicals, biological agents, toxins, etc. are associated with cancer development. In this section, national trends data associated with environmental exposures and their relationship to cancer are reported.

Secondhand Smoke

Secondhand smoke (SHS), also known as environmental tobacco smoke, is a mixture of the sidestream smoke released by the smoldering cigarette and the mainstream smoke that is exhaled by the smoker.

Chemical Exposures

Pesticides are chemicals used to eliminate or control unwanted or harmful insects, plants, fungi, animals, or microorganisms in order to protect food crops and other plants. Some pesticides have been classified as carcinogens. Chlordane and dichlorodiphenyltrichloroethane (DDT) are possible human carcinogens. General studies of people with high exposures to pesticides, such as farmers, pesticide applicators, manufacturers, and crop dusters, have found high rates of blood and lymphatic system cancers; cancers of the lip, stomach, lung, brain, and prostate; as well as melanoma and other skin cancers.

Dioxins are chemicals produced through paper and pulp bleaching; burning of municipal, toxic, and hospital wastes; certain electrical fires; and smelters. Dioxins can also be found in some insecticides, herbicides, wood preservatives, and cigarette smoke. There are at least 100 different kinds of dioxins, including Tetrachlorodibenzo-p-dioxin (TCDD). The most common routes of exposure for dioxins occur through the diet, particularly from animal fats.

Not all dioxins can cause cancer. TCDD is a particular dioxin that is likely to cause cancer in humans. The general population is exposed to low levels of TCDD primarily from eating dairy products, fish, and meat.

For more information, please  visit: www.cancer.gov.

Source: National Institute of Cancer