Researchers from the University of Pennsylvania School of Nursing have found that exposure to lead during early childhood is associated with increased risks of sleep problems in later childhood.
For the first longitudinal, population-based study about early lead exposure and sleep problems, Penn Nursing researchers used data from a cohort study that started in 2004 and involved over 1,400 Chinese children to investigate the effects of lead exposure to childhood development and adolescent health, behavioral and neurocognitive outcomes. Lead pollution is a big problem in China; exposure rates have dropped but the issue persists and presents a significant risk to child health.
Jianghong Liu, the study's principal investigator, said that not a lot is known about how exposure to heavy metals affects children's sleep but the study has shown that environmental toxins, like lead, are crucial pediatric risks factors associated with sleep disturbance. Liu pointed out that exposure to lead can be prevented but left unchecked can lead to irreversible damage to the brain.
"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 David Dinges, Ph.D., the study's senior author and chief of the Sleep and Chronobiology Division at Penn Medicine's Psychiatry Department.
Using data from the cohort study, the researchers assessed lead blood levels from 665 children at the time they were three to five years old. Sleep quality for these children were then assessed six years after their blood samples were taken, at a time they were nine to 11 years old. The children were also asked to fill out a questionnaire, as well as their parents.
Based on the results of the study, sleep problems prevalent in the subjects include insomnia, excessive daytime sleepiness, early morning awakening, difficulty initiating sleep and staying asleep, and the use of sleeping pills. Additionally, use of sleeping pills and insomnia were three and two times to be more prevalent in children with lead levels in their blood more than or equal to 10 ug/dL, respectively.
The study received funding support from the National Institute of Environmental Health Sciences/National Institute of Health, the Wacker Foundation and the University of Pennsylvania's Center of Excellence in Environmental Toxicology.
Other authors include: Xianchen Liu, M.D., Ph.D., Victoria Pak, Ph.D., Chonghuai Yan, Jennifer Pinto-Martin, Ph.D. and Yingjie Wang.
Photo: Amanda Truss | Flickr
