NCPA - National Center for Policy Analysis

Misconceptions about Cancer Skew Public Demand for Regulatory Protections

March 21, 2003

Common misconceptions underlie many fears about what causes cancer, say scientists from the University of California, Berkeley. This alarmism, they say, distracts from efforts to improve public health through scientific understanding and public education on how lifestyle influences health.

A common misconception is that potential cancer hazards are the result of human exposures to synthetic chemicals. In fact, the major avoidable causes of cancer are:

  • Smoking, which accounts for 27 percent of cancer deaths in Canada and 80 percent to 90 percent of deaths from lung cancer;
  • Dietary imbalances, such as a lack of sufficient amounts of dietary fruits and vegetables, which account for about another third;
  • Chronic infections, mostly in developing countries;
  • And hormonal factors, which are influenced primarily by lifestyle.

Another misconception is that cancer rates are soaring. Actually, since 1971, overall cancer mortality rates in Canada (excluding lung cancer) have declined 17 percent in women and 5 percent in men.

Synthetic chemicals at levels found in the environment have not been shown to be an important cause of cancer. But people are exposed to low levels of many naturally occurring carcinogens. Plants in the human diet contain thousands of natural "pesticides" produced by plants to protect themselves from insects and other predators: 72 have been tested and 38 have been found to give cancer to rodents.

Current policy is directed toward regulating exposures to synthetic chemicals that bear low, hypothetical risks. It is not effective in advancing public health.

The study concludes that the prevention of cancer will come from knowledge obtained from biomedical research, better education of the public and lifestyle changes made by individuals. A re-examination of priorities in both research investment and regulatory focus regarding cancer prevention is necessary.

Source: Lois Swirsky Gold, Thomas H. Slone, Neela B. Manley and Bruce N. Ames, "Misconceptions about the Causes of Cancer," February 2003, Fraser Institute.


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