School-Age Lead Exposure Damages IQ

Lead is a threat across a child's early years. (Photo: weedezign/Shutterstock)

Most kids today are tested for exposure to lead around their first birthday. Up until now, the concern regarding lead poisoning has focused on a child's developmental first year. But a new study shows that testing only at this young age may be missing a critical window when children are even more susceptible to lead poisoning ... their school-age years. According to a report that will be published in the current issue of Environmental Health Perspectives, lead exposure that occurs during a child's school-age years correlates more strongly to developmental disorders and a diminished IQ than earlier exposure.

The study was headed by Dr. Richard Hornung of Cincinnati Children’s Hospital Medical Center. Researchers analyzed data on lead levels and IQ from 462 children. About half of the data were collected from kids in Cincinnati during the early 1980s, the rest from kids in Rochester, N.Y., during the mid-1990s.

The researchers compared the children's IQ at age 6, the youngest age IQ can reliably assessed, with ratios of lead levels. The team looked at the ratio of lead at each age through age 6 to age 2. They also compared IQ with the average lead value through age 6 and with a child’s peak lead value. Their research showed hands down that lead ratios at ages 5 and 6 were most predictive of IQ losses.

The study shows children have windows of vulberability to lead exposure above and beyond their infant years. It's yet another thing that both parents and health care professionals need to be on the lookout for as kids get ready for school.