14 October 2011

Growing List of Suspected Carcinogens Demands Study in Diverse Workplaces:

The study of occupational hazards in the workplace has greatly broadened scientific understanding of the many causes of cancer. About a third of the factors labeled as either definite human carcinogens such as asbestos, arsenic or benzene or probable carcinogens were first studied as occupational hazards, according to scientists at the National Cancer Institute in Bethesda Maryland.

In a recent article published in the journal Environmental Health, the NCI scientists write that many additional occupational hazards are suspected causes of cancer in humans and require further study. Many occupational carcinogens may cause cancer in more than one part of the body, they say. For example, asbestos is strongly associated with pleural mesothelioma, a cancer of the lining of the lung; peritoneal mesothelioma, a cancer of the abdominal cavity lining; as well as lung cancer and cancer of the larynx, according to the researchers.

Of the long list of probable carcinogens compiled by the International Agency for Research on Cancer, occupational hazards represent 42 percent of the probable and possible carcinogens. Information gleaned from investigation of suspected workplace carcinogens may reduce cases of cancer among the general public because most occupational carcinogens also are found outside the workplace.

Many industries, for example, used asbestos, a cheap, durable mineral fiber, in a wide array of building materials, automotive and industrial products, coatings, and insulation materials. Workers who toiled in those industries face an  occupational hazard of exposure to asbestos. Typically, symptoms of mesothelioma appear several decades after exposure.

The use of asbestos is now restricted in the U.S. But many older houses and buildings still contain large amounts of asbestos-containing building materials that can cause cancer if disturbed by remodeling or demolition. Asbestos poses a hazard to both workers in specific occupations such as construction, demolition, plumbing and ship repair as well as to the general public. About 3,000 people are diagnosed with mesothelioma in the U.S. each year, and many are older workers, retired workers and veterans, particularly Navy veterans.

Most of the early studies of workplace carcinogens came from developed countries such as the United States and Western European countries. With the movement of many industries from developed countries to developing nations, the researchers says that it is important to expand research on occupational research to more diverse populations.

The use of asbestos in the 21st century has shifted to developing nations such as India, the Russian Federation and parts of Asia where weak or non-existent workplace safety laws presage an epidemic of mesothelioma in future decades.

The list of known and suspected workplace carcinogens continues to grow. But the scientific effort to identify occupational hazards has tapered off, according to the article. From the World Health Organization’s rating of carcinogens in 1964 to the list published by the International Agency for Research on Cancer in 1982, the number of suspected workplace carcinogens increased from 9 to 92, according to the researchers. From 1982 to the IARC’s more recent evaluation in 2003, the number of suspected carcinogens increased from 92 to 137, a much smaller rate of increase.

The researchers say that the number of investigators engaged in the study of occupational carcinogens has decreased considerably over the past two to three decades. They say the success of occupational studies in pinpointing deadly hazards and the large number of suspected carcinogens make a strong case for a significant public health focus on cancers in the workplace.

Source: About Mesothelioma. By Wade Rawlins. 7 October 2011

No comments: