Adults exposed to lead may lose memory and other brain functions earlier than normal, according to a new study. Investigators call their finding the "first of its kind" since most lead research has focused on children.

"There had really never been any studies that tried to figure out whether if you're exposed to chemicals that could damage your nervous system during your adult life--for example, at work--whether the change in your cognitive function over time differs from that of the general population," says Brian Schwartz, MD, one of the study's authors and associate professor and director of the division of occupational and environmental health at the Johns Hopkins School of Hygiene and Public Health in Baltimore, Maryland.

Researchers wanted to evaluate the effects of lead exposure in older adults, at an age when the nervous system was vulnerable. So they measured the lead levels in the bones, and the brain functions of 535 former chemical plant workers with 118 people from the same neighborhoods.

"We found that the more lead there was in the bones, the more rapid the cognitive decline over time was," says Schwartz. "We also found that the cognitive decline due to lead was almost as big as the cognitive decline due to age. So we found that the average lead in the bones of these workers was equivalent to about 5 more years of aging."

The study revealed significant differences between the plant workers' and the other participants' brains when it came to performing the following tasks: calling up memory, learning, planning and organizing and showing manual dexterity.

Comparing the bone lead levels in all participants was also interesting, says Schwartz, who notes that the levels were about the same in both groups. "Number one, this suggests that we had had a significant amount of lead in the environment over the years, and number two, because these guys [the factory workers] had been out of lead exposure at work for 16 years, the amount of lead in the bones could decline.'"

It's not yet known whether the findings could apply to the general population, Schwartz says, but there are plans to conduct more research on the matter.

According to an official at the Environmental Protection Agency (EPA), high lead exposure during adulthood has been shown to lead to reproductive troubles, high blood pressure, some nervous disorders, and memory and concentration problems. Neurological effects due to lead exposure during childhood could also reportedly carry on in later life.

Adults and children typically come in contact with lead by exposure to lead-based paint or dust, particularly if they are around a structure that was built before 1978 or has decaying paint. Concerned individuals could ask their physicians for a blood lead screening to find out if they have high levels of exposure.

Schwartz's study appears in the October 24 issue of Neurology, the scientific journal of the American Academy of Neurology.

(From CBSHealthWatch)