Air Pollution: A Suspect in Childhood Leukemia

Childhood leukemia is the most common form of cancer affecting children. The causes are not well understood, but some experts believe that toxic compounds in air pollution may play a role in the development of childhood cancer, especially leukemia. Because children go through periods of rapid growth and development, it can be assumed that they are more vulnerable to the effects of air pollution, and experts believe that their bodies may metabolize toxins in a different way than adults do. Previous studies have provided evidence of this increased sensitivity. The authors of a study in Environmental Health Perspectives studied the records of children with cancer in eight Texas counties, in order to determine the effect of higher levels of certain pollutants.

Benzene, a hazardous air pollutant, is a known human carcinogen. The compound 1,3-butadiene is a suspected carcinogen. The adverse effects of these compounds have been studied in both animals and humans. Chinese workers exposed to benzene on the job experienced significant decreases in their white blood cell and platelet counts. Although we are all exposed to background levels of benzene and 1,3-butadiene, people living in high-traffic urban areas, or near facilities belonging to the chemical and petroleum industries, are likely to be exposed to higher levels. Previous studies have reported an increase in the risk of childhood cancer in areas with the highest measured levels of benzene and 1,3-butadiene.

The area of study included Harris County, with a large number of petroleum and chemical facilities, and the city of Houston, with its large system of roadways. These eight counties were considered a model location for studying childhood cancer risks associated with exposure to benzene and 1,3-butadiene. The authors examined the medical records of 997 children living in the study area. All patients were younger than 20 years of age, and suffered from all types of leukemia, including acute lymphocytic leukemia (ALL), and acute myeloid leukemia (AML), the two most common forms of childhood leukemia, as well as non-Hodgkins's lymphoma (NHL), and Hodgkin's disease.

The authors of the study reported that areas with the highest levels of benzene had higher levels of all types of leukemia, and AML, when compared with areas of lower benzene concentration. No significant difference was observed in the rate of ALL, and no association was observed for Hodgkin's disease, or NHL. Higher rates of all types of leukemia were observed in areas with the highest levels of 1,3-butadiene in the air. The authors also observed higher rates of ALL and AML, compared with areas with the lowest levels, although these were not statistically significant. No association was observed in the rates of Hodgkins disease, or NHL. The authors of the study demonstrated an association between benzene and childhood cancer, and a possible association with 1,3-butadiene.

The authors concluded that more research is needed to determine the effect of other pollutants, and mixtures of pollutants on cancer in children, particularly leukemia. Ignoring evidence like this means closing our eyes to the harm caused by air pollution. The consequences of pollution to the health of our planet have been well documented. Childhood cancer is the number two killer of children in the United Sates, and the experts cannot tell us why. However, the 188 compounds classified as hazardous air pollutants are all suspect. For the sake of those who have died, and those fighting to live, we need answers to an urgent question. What is air pollution doing to our children?

Reference

Whitworth, K., Symanski, E., Coker, A.

Childhood Lymphohematopoietic Cancer Incidence and Hazardous Air Pollutants in Southeast Texas, 1995-2004

Environmental Health Perspectives