A little A preliminary study from Australia offers a tantalizing clue as to what could cause sudden infant death syndrome, but doctors warn that much more research is needed to find out if the results are conclusive in a larger group of infants.
The study, published May 6 in the journal eBioMedicine, is causing a stir among parents and spreading on Twitter and blogs.
It measured the levels of an enzyme called butyrylcholinesterase, which helps control the autonomic nervous system, in the blood of 67 babies in Australia who died of SIDS. Researchers from the University of Sydney and Westmead Children’s Hospital found that these levels were significantly lower in babies who died of SIDS than in babies who did not.
The researchers were careful to title their paper “Butyrylcholinesterase is a potential biomarker for sudden infant death syndrome,” noted Dr. Rachel Moon, SIDS researcher at the University of Virginia School of Medicine in Charlottesville. .
“This is an extremely small study, with 67 cases and 10 controls,” she said. “There’s nothing definitive about this. It’s certainly not confirmed to be ‘the cause of SIDS’.”
She said the strong parental interest in Australian research, while understandable, was not yet justified. While the enzyme levels were statistically different, there was enough overlap in cases and controls that a blood test wouldn’t be useful at the time, Moon said.
Additionally, some infants in the control group had the biochemical abnormality but did not develop SIDS. The lab samples tested were more than two years old and enzyme levels may have changed since the time of collection, said Dr. Jason Nagata, a professor of pediatrics at the University of California, San Francisco.
SIDS is the leading cause of death among infants aged one month to one year in the United States with at least 3,400 deaths each year
The Back to Sleep campaign in the 1990s to get parents to put their babies to sleep on their backs instead of stomachs was linked to a drop in SIDS deaths of more than 50%, according to the National Institute of Child Health. and human development.
Since then, researchers have better understood some of the underlying issues that cause babies to inexplicably die in their sleep.
Babies who die from the syndrome seem less able to self-resuscitate and wake up when their breathing is impaired, as can happen when they sleep on their stomachs.
“A normal baby might gasp and wake up if his breathing was obstructed while sleeping,” said Dr. Richard Goldstein, SIDS researcher at Boston Children’s Hospital.
Infants who die of SIDS do not seem to have as strong arousal response. “At least some of these babies are not struggling but are dying very quietly,” he said.
For these infants, their biology, rather than a preventable suffocation event, is the underlying danger. These threats are subtle and the child could survive if they did not have these biological vulnerabilities, he said.
To be clear, no one is saying that sleeping on your stomach is safe for babies. All infants should sleep on their backs because some — and it’s impossible to know which ones — are particularly at risk for SIDS when they sleep on their stomachs, Goldstein said.
Nagata added that mothers should also avoid smoking during pregnancy and receive regular prenatal care.
Genetic and molecular markers linked to some cases of SIDS have been discovered in recent years.
For example, a Harvard group led by Goldstein found genetic variants linked to 11% of SIDS cases, including cardiac, neurological and congenital syndromes. A Mayo Clinic study found that 4% of SIDS deaths were caused by a cardiac arrhythmia gene.
The results of the Australian study are “provocative” and “a good start”, but will require much larger studies to show that butyrylcholinesterase levels could predict which infants are at risk of dying from SIDS, Goldstein said.