New SIDS Study Suggests Reason Infants Die In Sleep

The new SIDS study leaves experts hopeful, but they advise caution when interpreting results

“I found my little grandson lying dead in his crib.”

I’ve listened to many sad and shocking stories over my 23 years running a Red Cross first aid training agency. Emotional accounts of an infant lost to Sudden Infant Death Syndrome are the most heartbreaking. Finding a beloved baby lying dead in their crib is a parent or grandparent’s worst nightmare.

A person’s feelings of grief and guilt when an infant dies on their watch are extreme. They wrack their brains to figure out what they could have done or not done to prevent the baby’s death. Attending a first aid course is often on their long list of self-imposed safety precautions to help avoid future tragedy. This is how I come to hear their stories.

According to a UNICEF report, globally, an estimated 2.5 million newborns die each year in the first month of life — approximately 7,000 babies every day. SIDS remains the leading cause of infant mortality in Western countries.

Thanks to new research and a world-first breakthrough at The Children’s Hospital at Westmead (CHW), Australia, there is hope that SIDS may soon be a thing of the past.

What is SIDS?

Sudden infant death syndrome (SIDS) is also known as cot death or crib death. It is the sudden unexplained death of a child under 12 months of age. For a diagnosis of SIDS to be given, the death must remain unexplained even after a thorough autopsy and detailed death scene investigation.

SIDS most often occurs during sleep, and typically, death occurs between midnight and 9:00 a.m. Usually, there is no noise or evidence of a struggle.

Public health campaigns such as the Back to Sleep program have significantly reduced deaths from SIDS. However, it is still responsible for half of all post-neonatal deaths.

Background to the research study

For years, medical experts have suspected that a defect in the part of the brain that controls arousal from sleeping and breathing is what causes SIDS. They theorized that if an infant stopped breathing while asleep, the defect would keep the child from waking up. Until recently, the arousal mechanism remained a mystery.

Researchers have now identified Butyrylcholinesterase (BChE) in the blood of newborns. BChE is the first biochemical marker that could help detect babies more at risk of SIDS while they are alive.

What is BChE?

BChE plays a significant role in the brain’s arousal pathway. Researchers believe a BChE deficiency likely indicates an arousal deficit, which reduces an infant’s ability to wake or respond to the external environment, making them more vulnerable to SIDS.

BChE and smoking

Smoking during pregnancy is one of the risk factors for SIDS, along with family history, premature birth, room temperature, a baby’s sleeping position and other factors. The researchers noted that animal studies have shown a tie between secondhand smoke and lower BChE. However, many other changes in the first six months of life are also likely to affect these enzymes and the nervous system in general.

About the new SIDS study

The study was published on May 6, 2022, in the Lancet’s journal eBioMedicine. Doctor Carmel Harrington, study lead, Honorary Research Fellow at CHW, dedicated her career to researching Sudden Infant Death Syndrome (SIDS) after her son Damien died from the condition in 1991.

“Twenty-eight years ago, I was a lawyer, who used to be a research biochemist and a mother of 3 gorgeous children, when one night my beautiful healthy baby son, Damien, died suddenly and without warning. I was told it was tragic and I was told to go home and enjoy my living babies and have more. I tried.”

You can read more of Dr. Harrington’s story here.

Study methods

The researchers measured levels of an enzyme called butyrylcholinesterase (BChE) and total protein in blood samples taken at birth from 67 babies aged 1–104 weeks. These babies died of SIDS and other unknown causes between 2016 and 2020. Technicians measured BChE in both SIDS babies and infants dying from other causes and compared them to ten surviving infants with the same date of birth and gender.

Findings and conclusion

Researchers found that the children who died of SIDS had significantly lower BChE levels than living children or those who died of other causes. They concluded that abnormal BChE, present at birth in SIDS babies, represents a measurable, specific explanation for SIDS death. In babies with a “Non-SIDS death,” there was no association between BChE and death.

Study limitations

The study size was relatively small. Other limitations include that the blood samples were more than two years old, so the findings don’t reflect BChE activity in fresh blood. The researchers also used coroners’ diagnoses rather than autopsy findings. They included data on children between one and two years old, where SIDS is usually defined as involving a child under a year old.

Hope for the future with a spoonful of caution

The new information offers hope to grieving parents, but more research is needed. Though this study has identified a potential biomarker for SIDS, a test for it is a long way off. Experts say it’s just one piece of the puzzle.

First Candle, a national organization focused on eliminating sleep-related infant deaths and supporting families, welcomed the research but also urged caution.

“This is progress, and for that, we should be optimistic, but it’s not the entire answer,” CEO Alison Jacobson said in a statement. “Our concern with the development of a test for the vulnerability to SIDS is with parents having a false sense of security and adopting unsafe sleep practices.”

Final thoughts

Individual scientific studies rarely offer clear-cut answers, especially to complex problems like SIDS. Research builds on itself over time. Research on the more fundamental, biological reasons for devastating issues like SIDS is essential to remove the stigma from grieving parents and help offer potential solutions. New and promising findings are helpful.

There’s still a long way to go before a screening test for SIDS might be available. However, this latest research is a promising step forward in understanding a devastating condition. BChE is a potential biomarker that might be used in the future to design a test (perhaps at newborn screening) to identify babies that might be vulnerable. The results from this study will likely lead to a reduction in heartbreaking deaths from SIDS, and that is something to celebrate.

Whenever new research uncovers a possible cure or unveils the answer to a long pondered question, we need to pause and look past sensational headlines blinking their attractive messages. We need to dig deeper into study methods, question the results and consider the consequences of hastily drawn conclusions.

Having a little patience, doing additional research and duplicating studies on a larger scale is wise. However, it doesn’t mean being so cautious we can’t celebrate legitimate advances in a particular field. It’s important to applaud the toil of dedicated researchers, acknowledge the pain of those for whom the study results mean the world, and hope for a better future.

In the case of the latest SIDS news, we need to keep an open mind, encourage and support research and hope for an end to SIDS in the very near future.

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