Childhood Lead Exposure Linked to Problems With Sleep, Daytime Drowsiness

Researchers from the University of Pennsylvania indicate that side effects of lead poisoning may cause sleep problems among children, in addition to the potentially severe developmental problems already linked to childhood lead exposure. 

In a study that will be published in next month’s issue of the medical journal Sleep, researchers found that young children with high lead blood levels were more likely to suffer sleep problems and excessive daytime drowsiness.

The research involved data on more than 1,400 children from China, where there is a high rate of high blood lead levels and lead poisoning. Blood lead levels were measured in children ages three to five, and their sleeping habits were assessed at ages nine to 13.

Researchers found that more than a quarter of children with blood lead levels of 10 micrograms per deciliter (mg/dL) were reported to suffer excessive daytime sleepiness, compared to less than 1% of children with low blood lead levels. Those with high blood levels were also found to be at double the risk of showing symptoms of insomnia.

“Little is known about the impact of heavy metals exposure on children’s sleep, but the study’s findings highlight that environmental toxins – such as lead – are important pediatric risk factors for sleep disturbance,” the study’s principal investigator, Jianghong Liu, PhD, associate professor at Penn Nursing, said in a press release. “Lead exposure is preventable and treatable, but if left unchecked can result in irreversible neurological damage.”

In July 2014, Liu led a team of researchers that determined that lead exposure causes behavioral problems even at very low levels.

In the United States, the CDC estimates that 535,000 children ages 1-5, or about 2.6% of such children nationwide, have levels of lead in their blood that place them at risk for adverse health effects. To come up with that number, the CDC analyzed data from the National Health and Nutrition Examination Survey from the years 1999 to 2002, and 2007 through 2010.

Lead poisoning for children is already known to increase the risk of nervous system injury, brain damage, seizures or convulsions, growth or mental retardation, coma and even death.

One of the more common causes of of lead poisoning is lead-based paint, which was banned in the United States in 1978 due to the risk of severe and permanent brain damage and developmental problems, particularly in children. However, a number of older homes still contain the toxic paint on the walls, and if it flakes or peals off, young children could ingest the paint chips or breathe dust that comes from the paint, resulting in lead poisoning.