Clinical

DDT exposure linked to liver cancer in humans

Last Updated: 2006-07-21 14:52:47 -0400 (Reuters Health)

NEW YORK (Reuters Health) - High serum levels of the pesticide DDT are associated with an elevated risk of primary liver cancer, according to the results of a case-control study conducted in China.

Previous reports have linked DDT and its degradation product DDE with liver tumors in laboratory animals. Whether exposure to this pesticide is associated with liver cancer in humans, however, has been less clear.

To investigate, Dr. Katherine A. McGlynn, from the National Cancer Institute in Rockville, Maryland, and colleagues analyzed data from 168 case patients and 385 age- and sex-matched controls who participated in the Nutritional Intervention Trials in Linxian. DDT and DDE serum levels were measured using gas chromatography-mass spectrometry.

The risk of liver cancer was directly related to the DDT serum level, Dr. McGlynn's group reports in the Journal of the National Cancer Institute for July 19. Subjects in the highest DDT quintile were 3.8-times more likely to develop liver cancer than those in the lowest quintile.

The DDE level alone was not significantly associated with liver cancer risk. However, in conjunction with a high DDT level, a low DDE level appeared to increase the risk further.

In terms of absolute risk, the highest DDT quintile was tied to a liver cancer rate of 46 cases per 100,000 persons per year compared with a rate of 26 cases per 100,000 persons per year for the lowest quintile.

The results suggest that DDT exposure may be a risk factor for hepatocarcinogenesis in humans, "especially in populations that are directly exposed to DDT, rather than just exposed to its metabolites," the authors conclude.

J Natl Cancer Inst 2006;98:1005-1010.