The cause of SIDS is not known, despite what a new study claims


Sudden Infant Death Syndrome, or SIDS, is every new parent’s worst nightmare. SIDS is the unexplained death of a sleeping infant less than 12 months old. It most often occurs between one and six months. Although the cause remains unknown, there are several well-known risk factors for SIDS, as well as several well-known measures to minimize these risks.

A study published in the open access journal eBioMedicine early May 2022 made headlines as his results indicated that a biochemical marker as the cause of SIDS had been found. The study group, based in Australia, analyzed blood samples taken at birth from more than 600 newborn babies. Those who died from SIDS were found to have relatively low levels of a substance known as BChE, or butylcholinesterase. Low levels of BChE have been explored as potential biomarkers for neurodegenerative diseases such as Alzheimer’s disease. This substance works in the part of the nervous system called the autonomic nervous system, which is responsible for bodily functions such as regulating blood pressure and respiratory rate and drive. The study results suggest that if an infant’s BChE level is low at birth, it could be a marker of SIDS in the coming months.

Within days, this story went viral, with many media outlets praising the researchers for finally finding the cause of SIDS.

But then came the break. As is often the case in science, if it sounds too good to be true, it probably is. While this finding may, indeed, be a marker to explore further, calling it the cause of SIDS isn’t just an exaggeration, it isn’t either. At least not to our knowledge. Still.

As described by Dr. Benjamin Mazer in the May 17, 2022 issue of Atlantic, the explosion of results from this small study skipped so many critical steps in the scientific process of learning the cause and effect of a fatal event. The study, which examined the blood of 600 babies, 26 of whom died from SIDS, found globally lower levels of BChE than those who did not succumb. But this was on average a lower level, not an “all or nothing” binary on or off switch. It’s not that the study wasn’t good, it’s that it wasn’t a definitive “cause and effect” study. It was hardly an “association”. Some babies who did not die from SIDS had low levels of BChE. Some people who died had normal levels of BChE. Could there be an association between low levels of BChE and the risk of SIDS? Certainly. But calling it the cause, based on this small study, is not possible.

As Dr. Mazer points out, even if low BChE was found to be a notable biomarker of SIDS risk, we already know that there are multiple risk factors for SIDS and many ways to reduce those risks. Foregoing these mitigation measures would be dangerous.

In the 1990s, the American Academy of Pediatrics launched the “Back to Sleep” campaign, urging parents and caregivers to place newborns on their backs when placing them to sleep. This position greatly reduces the risk of suffocation if an infant’s nose and mouth are flat against a crib sheet, and also reduces the risk of an infant re-breathing their own carbon dioxide while facing downward. down while sleeping. This campaign increased awareness of this and other safe sleep practices, resulting in a reduction in the annual number of SIDS deaths each subsequent year.

However, even with the benefits of safer sleep practices, SIDS remains a devastating event for many thousands of infants each year in the United States alone. Besides sleeping on your stomach, there are other known risk factors for SIDS, such as a history of premature birth, exposure to second-hand smoke, use of a soft crib mattress, or the presence of blankets , pillows or toys in a crib, and overheating a baby while sleeping. .

To reduce the risk of SIDS, a baby should sleep on their back on a firm crib mattress with no blankets, pillows, crib bumpers, or toys. The room temperature should be comfortable but not too hot. Higher ambient temperature (and summer months) tend to be associated with (but not the cause of) SIDS.

Indeed, if there had been a clear cause, or few causes, for the horror of SIDS, it would be cause for absolute celebration. Unfortunately, this is simply not the case. The findings are valid and potentially an important piece of the very complex puzzle that is SIDS. But a tweet stating “They found the cause of SIDS,” which quickly went viral, is misleading at best and harmful at worst.


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