Cancer

Source: www.cancerhelp.org.uk Cancer occurs when cells grow uncontrollably. These abnormal cells reproduce at a more rapid rate than normal cells and outlive normal cells. They can occur in almost any part of the body.

Cancer cells develop due to damage to DNA. This damage can be inherited from the parents, caused by environmental factors, or a combination of the two (the so called gene-environment interaction). Cancer is the second leading cause of death in the United States. Half of American men and a third of American women will develop cancer during their lifetimes according to the American Cancer Society.

An estimated 75% of all cancer cases in the United States are caused by environmental factors. Recognized or strongly suspected environmental carcinogens include:

tobacco;
alcohol;
arsenic;
diesel exhaust;
poor diet or carcinogenic foods;
some viruses, including hepatitis B;
numerous chemicals including benzene, styrene, vinyl chloride and formaldehyde;
asbestos;
dioxins from incineration of plastics;
ionizing and ultraviolet radiation; and
radon gas from underground granite deposits.

The majority of man-made chemicals to which we are exposed have not been adequately tested for cancer-causing properties. Houston has higher concentrations of suspected carcinogens in the air than most cities, primarily because of its large concentration of petrochemical industries. Freeways are also major sources of carcinogens in many Houston neighborhoods. According to an L.A. study, commuting 1.5 hours a day exposes an individual to 60% of the carcinogens to which one is exposed in a 24-hour period.

The National Cancer Institute (NCI) and the National Institute of Environmental Health Sciences (NIEHS) created an excellent booklet regarding the connection between cancer and exposure to toxic substances in the environment. You can download this booklet here, or visit the NCI website.

Relatively few studies of cancer and environmental exposure have been done in the Houston area. One study, by Dr. Sharon Cooper and associates, looked at cancer deaths in Texas and in the Houston region (Cooper, 1998); she found slightly elevated rates for lung and bronchus cancer in the Houston area, but reduced rates of several other cancers, when compared with Texas and national averages.