According to University of Rochester Medical Center study people exposed to lead on the job are 50 percent more likely to die from brain cancer than people who are not exposed. The study author Edwin van Wijngaarden, Ph.D., said the study provides further evidence that widespread environmental risk factors such as lead must be explored. The study, which might be the largest study ever to find a lead-cancer link, was based on the information from the U.S. Census Bureau and the National Death Index.

More than 18,000 brain and spinal cord tumors will be diagnosed in the United States this year. Yet little is known about what causes brain cancer; the only established risk factor is radiation, according to the American Cancer Society.

"If we are able to help explain the cause of even 1 or 2 percent of the total number of cases, that's important," said van Wijngaarden, an assistant professor and epidemiologist in the Department of Community and Preventive Medicine at the University of Rochester.

Published in the Sept. 1, 2006, issue of the International Journal of Cancer, the study computed the risk estimates for lead exposure and brain cancer from a census sample of 317,968 people who reported their occupations between 1979 and 1981. Van Wijngaarden was looking for evidence of an exposure-response trend, or a rise in cancer incidence or mortality associated with an exposure to a toxic substance. The goal among researchers who do this type of investigation is to identify preventable, environmental risk factors that might cause the gene mutations that lead to cancer.