Code 7

Many aspects of general health can be improved, and certain cancers avoided, if you adopt a healthier lifestyle

:: Apply strictly regulations aimed at preventing any exposure to known cancercausing substances. Follow all health and safety instructions on substances which may cause cancer. Follow advice of national radiation protection offices.The prevention of exposure to occupational and environmental carcinogens has followed the identification of a substantial number of natural and man-made carcinogens, and has led to significant reductions in cancer occurrence. The message in this item of the code solicits responsible behaviour for individuals in three respects:

1) from those who have to provide timely and clear instructions, primarily legislators and regulators who should adapt scientific consensus evaluations into European Union law, and control compliance with these regulations;

2) from those who should follow these instructions and comply with the laws to protect the health of others, for instance, managers, hygienists and doctors in industry; and

3) from every citizen who in order to protect their own health and the health of others, ought to pay heed to the presence of carcinogenic pollutants and follow instructions and regulations aimed at mitigating or preventing exposure to carcinogens

The latter applies to a wide variety of circumstances such as traffic restrictions within cities, restrictions on smoking, use of personal safety devices and respecting validated procedures in the workplace. Application of regulations is particularly important in the working environment where carcinogens may be found in higher concentrations than in the general environment. The control of the prevalence and level of exposure to occupational and environmental carcinogens through general preventive measures has historically played a more important role in preventing cancers than individual measures of protection.

The cancers that have most frequently been associated with occupational exposures are those of the lung, urinary bladder, mesothelioma, larynx, leukaemia, angiosarcoma of the liver, nose and nasal cavity and skin (non-melanoma). Several other neoplasms have also been associated with occupational exposures but the evidence is less strong. They include cancers of the oral cavity, nasopharynx, oesophagus, stomach, colon and rectum, pancreas, breast, testis, kidney, prostate, brain, bones, soft-tissue sarcoma, lymphomas and multiple myeloma. Most known or suspected occupational carcinogens have been evaluated by the International Agency for Research on Cancer(IARC Lyon, France). Actually, 29 chemical or physical agents, groups of agents or mixtures that occur predominantly in the workplace, have been classified as human carcinogens (Group 1 of the IARC classification). In the same Group 1, IARC has classified 13 industrial processes or occupations, such as the rubber industry, painters, etc. In European Union countries, production or use of some of these chemicals has been banned and are only of historical interest (e.g. mustard gas, 2-naphthylamine), while some high-risk industries have stopped functioning (e.g. ‘Wismut’ uranium ore mining associated with exposure to ionising radiation). Exposure to other carcinogens such as metals and dioxins is still widespread.

Thirty-five agents or industrial processes are classified as probably carcinogenic to humans (Group 2A of the IARC). Many of the agents in this group are still widely used, for example 1,3- butadiene and formaldehyde. More than 200 agents, groups of agents or exposure circumstances are classified as possibly carcinogenic to humans (Group 2B) largely on the basis of carcinogenicity data from animal experiments. It has been estimated that in the early 1990s about 32 million workers (23% of those employed) in the European Union were exposed to carcinogenic agents at levels above background. Exposure to these agents is still widespread but occurs mostly at low levels. The more common occupational exposures are solar radiation, passive smoking, crystalline silica, diesel exhaust, radon, wood dust, benzene, asbestos, formaldehyde, polycyclic aromatic hydrocarbons, chromium VI, cadmium and nickel compounds. Extensive preventive measures in the workplace in recent decades have resulted in the prevention of many cancers related to workplace exposures. This has been well documented, for example for occupational bladder cancer after the ban on the use of beta-naphthylamine in the rubber and chemical industries. The delays in taking protective measures, however, and the long latency for many neoplasms will result, in certain instances, in a continuous increase in the number of occupational cancers during the coming years. An increasing number of mesothelioma cases due to past occupational exposure to asbestos is expected in many European Union countries for another 10–20 years, even though asbestos has been banned in some European Union countries since the early 1990s. The proportion of all cancers that can be causally attributed to carcinogens in the occupational environment and are therefore wholly or partially avoidable through exposure control, remains difficult to quantify reliably. An estimated 5% of cancers is attributable to the occupational environment. This proportion depends on the variable prevalence of the exposures by geographical areas, gender, socioeconomic status and periods of time, as well as on the concurrent prevalence of other dominant cancer causing factors, particularly tobacco smoking. Furthermore, the effect of specific occupational carcinogens, such as aromatic amines or polycyclic aromatic hydrocarbons, is also mediated by genetic factors, such as genetic polymorphisms of the NAT2 or GSTM1 genes. The distribution of these polymorphisms within the populations of the European Union is fairly uniform and genetic factors probably do not determine differences in the proportion of occupational cancers between populations in European Union countries.

Environmental exposures usually refer to exposures of the general population that cannot be directly controlled by the individual. They include air-pollution, drinking water contaminants, passive smoking, radon in buildings, exposure to solar radiation, food contaminants such as pesticide residues, dioxins or environmental estrogens, chemicals from industrial emissions, and others. Exposure may be widespread, as is the case for air pollution, or could be restricted, as would be the case of populations living in the vicinity of a contaminating industry. These exposures have been associated with a variety of neoplasms, including cancers of the lung, urinary bladder, leukaemia and skin. The impact of several environmental carcinogenic exposures, such as arsenic in drinking water, has not been quantified, though exposure to arsenic is likely to affect only limited population groups. Air pollutants, such as fine particles, have been associated in several studies with a small increased risk of lung cancer even at current low-level urban exposure levels. The evidence on other exposures that are widespread, such as disinfection by-products in drinking water, is still inconclusive. Agents in the general environment to which a large number of subjects are exposed for long periods, such as passive smoking or air-pollution, although increasing only modestly the relative risk for certain cancers may be at the origin of several thousand cases per year in the European Union.

It is essential that for any agent liable to present a risk, the nature, degree and duration of such risk must be determined in order to define what measures need to be taken to prevent or reduce the exposure. Among these measures, suitable operating procedures and methods are of utmost importance. Instructions to be followed may take the form of quantitative control limits of exposure, derived empirically or through formal procedures, which still leaves much to be desired. The specification of a quantitative control limit of exposure in the general and occupational environment combines two elements: the quantitative estimate of the risk associated with a given level of exposure and the level of risk regarded as socially “acceptable”, with consideration of the technical feasibility, and human and economic costs of various degrees of control.

Related:

Ionising and Non-Ionising Radiation

Cosmic Radiation And Cancer

Radioiodine and thyroid cancer

Nuclear workers

Populations living near nuclear installations

Power lines and cancer

Cellular telephones and cancer

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