Youth who are exposed to lead may have a harder time getting a good night’s sleep, which may affect their cognitive abilities, according to a University of Michigan study in Mexico.
“One of the most consistent adverse consequences of lead exposure in kids is poor neurocognitive outcomes. And we also know that suboptimal sleep is highly related to neurocognitive issues in kids,” said Dr. Erica Jansen, research assistant professor at University of Michigan School of Public Health. “This highlights the possibility that sleep could play an intermediary role between lead exposure and cognitive outcomes.”
The study, published in the Journal of Clinical Sleep Medicine, included 395 participants from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) project, a group of sequentially enrolled birth cohorts from Mexico City that have been monitored for up to 25 years.
Blood lead levels were measured from ages 1 to 4 years and used to calculate a cumulative measure of early childhood lead levels. Average sleep duration, sleep fragmentation and movement during sleep were assessed once between the ages of 9 and 18 with wrist actigraphs worn for a continuous seven-day interval. These measures were then compared to lead levels divided into quartiles per exposure, adjusted for age, sex and maternal education.
“We did find associations between higher cumulative lead exposure over early childhood with shorter sleep duration measured in adolescence,” Dr. Jansen said. “Those in the upper 25 percent of blood lead levels slept, on average, 23 minutes less than those in the lowest 25 percent.”Friday Letter Submission, Publish on November 01