TUESDAY, May 23, 2006 (HealthDay News) -- Eighteen years after they were last exposed to lead on the job, workers showed significant brain cell loss and brain tissue damage, a new U.S. study shows.
The study included 532 former employees who'd worked at a chemical manufacturing plant for an average of eight years. At the time of the study, the workers had not been exposed to lead for an average of 18 years.
The amount of lead accumulated in the workers' bones was measured, and MRI scans were used to measure workers' brain volumes and to look for white matter lesions (small areas of brain tissue damage).
The study appears in the May 23 issue of Neurology.
Researchers found that 36 percent of the workers had white matter lesions. The higher their lead levels, the more likely workers were to have smaller brain volumes and greater amounts of brain damage. Workers with the highest levels of lead were more than twice as likely to have brain damage and to have brain volumes 1.1 percent smaller than those with the lowest levels of lead.
"The effect of the lead exposure was equivalent to what would be expected for five years of aging," study author Walter F. Stewart, of the Center for Health Research of the Geisinger Health System in Danville, Pa., and the Johns Hopkins Bloomberg School of Public Health in Baltimore, said in a prepared statement.
"The effect of lead on the brain is progressive. These effects are the result of persistent changes in the structure of the brain, not short-term changes in the brain's neurochemistry," Stewart said.
This study confirms earlier findings that workers suffered a decline in thinking and memory skills years after being exposed to lead.
More information
The U.S. Centers for Disease Control and Prevention has more about lead.
