Leukemia, occupational causes

The present status of knowledge in this field is far from relevant, hence one can neither incriminate nor refute the occupational causative factors for childhood cancer and leukemias. The positive associations of occupations and exposures having a higher risk could be used only in setting priorities for further research. 

Individuals working in a petroleum refinery are routinely exposed, over the course of an eight-hour work day, to the volatile hydrocarbon benzene, a constituent of petroleum that has been established through epidemiology studies, in quite different occupational situations, as a cause of human leukemia. Is it possible to understand whether and to what extent these specific, unstudied refinery workers are at risk of developing leukemia ... 

Let us assume that enough information is available regarding the levels of benzene in Mr. Z s well, the number of years he consumed the water, and even his water consumption rate, to derive a reasonably accurate estimate of his cumulative exposure from this source. The epidemiologists and biostatisticians carefully evaluate the dose-response data from the published epidemiology studies used as the basis for classifying benzene as a cause of leukemia. Further assume that we learn from this evaluation that Mr. Z incurred a cumulative benzene exposure approximately equivalent to the cumulative exposure that was found to cause a three-fold excess risk of leukemia in the occupational studies of benzene exposure. A relative risk of three. 

Floderus, B., T. Persson, C. Stenlund, A. Wennberg, A. Ost and B. Knave (1993). Occupational exposure to electromagnetic fields in relation to leukemia and brain tumors a case-control study in Sweden, Cancer Causes Control, 4, 465-476. 

Epidemiological studies have associated ethylene oxide with hematological diseases (mainly anemia, leukopenia, and leukemia) (SEDA-24, 271). To determine whether occupational exposure to low concentrations of ethylene oxide can cause hematological abnormalities and whether... 

One study demonstrated that parental occupational exposures to chlorinated hydrocarbons are associated with increased risks for leukemia, lymphoma, and urinary tract cancers in offspring. Another study showed associations between maternal exposures to solvents and increased incidences of leukemia. These solvents include 1,1,1-trichloroethane, toluene, and other mononuclear aromatic hydrocarbons, mineral spirits, and alkanes. Childhood brain cancers, the second leading cause of childhood cancer, have been associated with parental occupational exposures to toxic chemicals. Industries for which such associations have been found include 10 ... 

Benzene. Benzene is recognized as the most toxic compound among BTEX, because it has been proved that breathing very high concentrations of benzene in air can cause death and that long-term exposure to lower levels causes leukemia. The Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 1 ppm in the workplace during an 8-h day if 40 h a week are worked. 

Occupational exposure to tetrachloroethylene and other solvents did not generally result in increased risk of hematopoietic neoplasms. Although there was one report of familial chronic l5miphocytic leukemia in five of seven members of a family who had worked for years in the dry cleaning industry (Blattner et al. 1976), it appears that an inherited defect was ihe cause of this family s susceptibility to leukemia. In addition, there was a study on occupational exposure of parents whose children had acute nonl miphocytic leukemia. Paternal (but not maternal) exposure to agents categorized as "solvents" was reported to pose a significant risk for development of childhood leukemia (Buckley et al. 1989). However, the risk was... 

A distinct relation between parental occupational exposure and childhood cancer was shown for solvents and paints. High parental exposure resulted in higher incidences of childhood cancers. In the same study, however, generally more cancers were found as a result of parental use of alcohol and tobacco smoke. Childhood leukemia and nervous system cancers, in particular, are the types suspected to be caused by parental exposure to paints and solvents. Kishi et al. described an elevated risk for acute lymphatic leukemia in children of mothers with prenatal exposures to benzene and to paints. In former studies with small numbers of children these tendencies could also be shown, mainly in male painters whose children showed a higher incidence of childhood leukemia and brain tumors. 18.3.4.2.4 Respiratory effects... 

The evidence of several types of leukemia is convincing with regard to occupational exposures to paints and sol vents.Increased risks for contracting other haematopoietic neoplasmas such as Hodgkin s disease, non-Hodgkin s lymphoma, multiple myeloma, reticulum-cell sarcoma and lymphosarcoma were also reported. Probably all neoplasmas were caused mainly by organic solvents. Some former studies, however, included solvents which are rarely used now, especially benzene. ... 

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