The damaging effects that lead poisoning has been shown to have on children's ability to learn may be partially reversible, a new study published this month in the Journal of the American Medical Association has found.
In the study, researchers at the Albert Einstein College of Medicine in New York City gave edetate calcium disodium to 154 children ages 1 to 7 who had moderate lead poisoning but no apparent symptoms. The drug has been found to reduce lead levels in children's blood, the study says.
The children were also given iron supplements to guard against iron deficiencies, a condition that is known to aggravate lead damage. Researchers also decontaminated the children's homes to reduce their indoor exposure to lead.
While short-term effects were not apparent, they found that the children's cognitive development and test scores improved greatly six months after the treatments. A decrease of 3 micrograms per deciliter of lead in a child's blood level corresponded to a one-point increase in I.Q.-test scores, the report says.
The Public Health Service reported in 1990 that eight million children had harmful levels of more than 10 micrograms of lead in their blood.
Earlier studies have shown extended lead exposure causes learning retardation in children.
While their physical deformities eventually disappear, babies born with fetal-alcohol syndrome can suffer permanent brain damage, according to a study by three German researchers published in The Lancet, a British medical journal.
F.A.S. is the leading cause of mental retardation, but little is known about its lingering effects on adolescent development.
The researchers conclude in the 10-year follow-up study that "environmental and educational influences are less important to intellectual outcome of F.A.S. patients in adolescence than expected.''
Following 60 children born with F.A.S. between 1977 and 1979, the researchers found that the physical effects, including small heads, short stature, and low body weight, diminished over time but that intellectual capacity remained relatively stable.
Only one child moved from borderline intelligence to the normal range, while the rest showed no increase in I.Q., and three were assessed as learning-disabled.
The researchers also found that the children's school status declined. Of the 29 patients who attended regular preschools or primary schools, only 13 were still in mainstream schools a decade later.
The precise level at which alcohol begins to damage the fetus is
unknown. But, according to the researchers, F.A.S. occurs in two out of
every 1,000 live births worldwide.--J.P.