A new study has linked exposure to lead in early childhood with an increased risk for sleep problems and excessive daytime sleepiness in early childhood.
The new study from the University of Pennsylvania School of Nursing is based on data from a longitudinal, cohort study that began in 2004 involving more than 1,400 Chinese children to investigate how lead exposure influences children’s neurocognitive, behavioral, and physical health development.
Lead pollution is pervasive throughout China and other developing countries, said the researchers, who noted that while rates of lead exposure are decreasing due to the phase-out of leaded gasoline and increased public awareness, its persistence presents a significant health risk to children.
“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,” said the study’s principal investigator Jianghong Liu, PhD, FAAN, an associate professor at Pennsylvania Nursing and a faculty member at Penn’s Perelman School of Medicine.
“Lead exposure is preventable and treatable, but if left unchecked can result in irreversible neurological damage.”
Sleep problems, which are prevalent in children and adolescents, are associated with many adverse health outcomes, including developmental disorders and intellectual and neurocognitive problems, the researchers noted.
“This study addresses an important, but often neglected, area of sleep science, namely, environmental factors that disrupt sleep biology and behavior in children and other vulnerable populations,” said the study’s senior author David Dinges, Ph.D., chief of the Division of Sleep & Chronobiology in the Department of Psychiatry at Pennsylvania Medicine.
Sleep problems reported by the adolescents in the study include excessive daytime sleepiness, insomnia, early morning awakening, trouble initiating and maintaining sleep, and having to use sleeping pills.
Using the data from the cohort study, 665 children’s blood lead levels were assessed when they were between three and five years old, and sleep was assessed six years later, when the children were between nine and 11 years old.
The children and their parents also answered separate questionnaires about the children’s daily sleep patterns, insomnia, and the use of sleeping pills.
Child-reported insomnia and the use of sleeping pills were two times and three times more prevalent in children with blood lead levels (BLL) greater than or equal to 10 ug/dL than in children with BLL less than 10 ug/dL, the study discovered.
This suggests that sleep disturbances appeared problematic enough for children to suffer from insomnia and even to use sleeping pills in an attempt to ameliorate their symptoms, the researchers said.
According to Liu, more research is needed to identify contributing factors and ways to prevent or reduce their impact.
“Doing this cannot only help alleviate sleep disturbance, but can also indirectly improve sleep-related health outcomes, including cognition, emotion, behavior and, in some cases, diabetes,” she said.
The study was published in SLEEP.