November 20, 2008 - (BRONX, NY) - Parents should pay close attention to the quality of their kids' sleep because snoring and other nighttime breathing problems could stunt a child's growth. That's according to a study led by researchers at Albert Einstein College of Medicine of Yeshiva University.
As many as one in five children experience breathing problems during sleep, such as snoring, mouth breathing, and apnea (abnormally long pauses in respiration). Researchers have long suspected these problems - collectively known as sleep disordered breathing (SDB) - contribute to growth delays in children. SDB interrupts deep sleep, a period of the sleep cycle when the body typically secretes large amounts of growth hormone. Children with SDB are thought to produce a lesser amount of growth hormone.
Many small studies have looked at the connection between SDB and growth, but none was large enough to draw definitive conclusions. In an attempt to gain clarity, Karen A. Bonuck, Ph.D., associate professor of family and social medicine at Einstein, and her colleagues collected and re-analyzed data from 20 well-designed studies, a statistical technique known as a meta-analysis.
These studies involved children with enlarged tonsils and/or adenoids - the principal causes of SDB. (Other causes of SDB include obesity, neuromuscular weakness of airway muscles, and craniofacial abnormalities.) All the children had their tonsils/adenoids surgically removed, either to treat symptoms of SDB or recurrent infection, or both. They were then monitored to measure the impact of the surgery - which is usually curative - on growth.
"Our meta-analysis found significant increases in both standardized height and weight following surgery," says Dr. Bonuck, whose paper was published online by Archives of Disease in Childhood. "In other words, while all the children were expected to continue to grow after they underwent surgery, their growth rates were much greater than expected."
These results are particularly important because studies show that only one in two pediatricians is aware of any potential link between SDB and growth failure.
"Our findings suggest that primary-care providers and specialists should consider the possibility of SDB when they see children with growth failure," says Dr. Bonuck.
The American Academy of Pediatrics recommends that pediatricians should routinely screen all children for SDB symptoms during well-child visits. "Parents are typically asked how their child is sleeping, but this is often taken to mean total sleep time, rather than sleep quality," says Dr. Bonuck.
For parents, the take-home message is to be alert to symptoms of SDB, particularly habitual snoring, which tend to peak during the preschool years. Such monitoring may help prevent growth delays in children from occurring in the first place, she says.
Growth delays are not the only reason why parents need to be attuned to SDB symptoms, adds Dr. Bonuck. SDB is also associated with increased risk of behavioral or cognitive issues, such as attention-deficit hyperactivity disorder (ADHD) and other learning disabilities.
Most cases of SDB can be diagnosed with a comprehensive history and physical examination. In more complicated cases, an overnight stay in a sleep center may be warranted.
Increased screening and treatment of children for SDB could result in considerable cost savings, the researchers note. Growth hormone therapy, which is commonly used to treat children with growth delays, averages $15,000 to $20,000 a year in young children and can exceed $50,000 a year in adolescents. "In contrast, removal of the tonsils or adenoids is a one-time intervention, and can be done at a fraction of the cost."
Dr. Bonuck's co-authors include Katherine Freeman, M.S., Dr.P.H., professor of epidemiology and population health at Einstein, and John Henderson, M.D., a principal investigator of the Avon Longitudinal Study of Parents and Children (ALSPAC), based at the University of Bristol in Bristol, England.
Dr. Bonuck recently received a two-year, $400,000 grant from the National Institutes of Health to conduct further studies into the relationship between SDB and growth. The study will follow nearly 14,000 children from birth through puberty.