The epidemiology of asbestos-related diseases.

Asbestos has been recognised as a potential health hazard since the 1940s. Of the two major species of asbestos; white asbestos (chrysotile) and blue asbestos (crocidolite), both of which are hazardous. The workers at extraction facilities are at the greatest risk of exposure to asbestos and, therefore, the development of asbestos-related diseases, commonly mesothelioma. However, other individuals at a high risk of exposure include asbestos-cement workers, insulation workers and ship-yard workers. Environmental exposure to asbestos can occur as a result of living in areas either characterised by natural outcrops of asbestos or asbestos-related materials, or those close to asbestos-producing or -using plants. Unfortunately, man-made fibre alternatives to asbestos, such as rock and slag-wool and glass wool, have also been shown to have a detrimental effect on human health. A characteristic of mesothelioma is that there is a long latency period (20-30 years) before the signs and symptoms of the disease become apparent. In addition, diagnosis of the disease can be difficult. The use of biological markers, such as tissue polypeptide antigen, may play a useful role in the early detection of the disease in individuals at risk.

Immunologic and other biological parameters as a function of smoking status and of residence in areas differing in terms of air pollution.

In the industrial region of La Louvière (Belgium), healthy persons, presenting at a consultation of preventive medicine, showed differences as a function of smoking and of residence in one of four areas differing in sources of emissions, population density and green zones. Smokers had significantly (P/=2.25, significantly so for the Power Station-Landfill area. A non-significant but consistent trend towards higher lymphocyte and CD8 lys counts and higher complement C3c serum levels further suggested an association between residence in a more polluted area and immunologic features. The number of CD3+CD56+ lys microl(-1), reported to be increased in cancer patients, showed a negative correlation with the CD4/CD8 ratio (r(2)=0.132, P<0.0001).