Paying Attention

The Roman aristocracy routinely drank wine sweetened with lead, which may, given what we now know about that heavy metal, have contributed to the mad behavior of its emperors. Recent research is focusing on the possible relationship between lead and other neurotoxins -- substances which impact the central nervous system and brain -- and such disorders as Attention Deficit/Hyperactivity Disorder (ADHD) and Parkinson's Disease. In 1999, this relationship was raised at conferences on children's health at the Mount Sinai School of Medicine in New York City and at the University of Arkansas for Medical Sciences.

Attention Deficit Disorders

At least 3-5% of children in the U.S. are thought to have ADHD, a learning disability characterized by inattention, impulsivity, and hyperactivity. And the condition is on the rise. "Studies have consistently shown a relationship between lead and inattention and hyperactivity," reported Herbert Needleman, M.D., of the University of Pittsburgh School of Medicine. While high levels can harm a child's growth, hearing and speech, small amounts can cause damage, too. Dr. Needleman is exploring the correlation between lead levels in bones, where lead is stored, and severity of ADHD in 250 children.

Polychlorinated biphenyls (PCBs) also affect children's brains at relatively low levels, according to two longterm studies of children exposed to PCBs in the womb as the result of mothers' consumption of contaminated fish. Wayne State University researchers followed 212 children from birth through age 11 and found that kids exposed to PCBs in utero had greater incidence of diminished I.Q., attention and memory. In Arkansas, researchers from the State University of New York, Oswego, presented new evidence that the interaction of PCBs and mercury, another potent neurotoxin, can adversely affect children's ability to learn.

Parkinson's Disease

Parkinson's Disease (PD), a progressive, degenerative disorder, generally occurs in those older than 50. Genetic factors are not responsible for PD in older adults, the January 1999 Journal of the American Medical Association reported. If genes aren't the culprit, then environmental factors, including exposure to neurotoxic chemicals, may be, said Philip Landrigan, M.D., M.Sc., director of the Center for Children's Health and the Environment at Mount Sinai. For instance, several studies over the past decade have reported elevated risks of PD in people exposed to pesticides.

- Molly Rauch, M.P.H., is a health writer in New York City.