Over the last couple of weeks, I’ve received several messages about a “miraculous” study which has sent social media and news outlets into a frenzy, proclaiming that researchers had identified the cause of Sudden Infant Death Syndrome (SIDS). A press release about the study went a step further, asserting that the “game-changing” findings “could prevent SIDS” and quoting lead study author Dr. Carmel Harrington in saying, “we can begin to change the outcome for these babies and make SIDS a thing of the past.”
The news has brought relief, comfort, hope, and outright celebration from new and expectant parents as well as those who have previously lost children to SIDS. The story quickly circulated through social media, where many hailed it as a miracle that came with a promise that SIDS prevention was just around the corner. Parents shared emotional stories of children lost and of wakeful nights spent worrying. But sadly, these parents – and many others reading these reports – have been cruelly, and perhaps even dangerously, misled.
What did the study find?
Dr. Harrington’s study did not find the cause of SIDS, and it certainly didn’t discover a way to prevent it. What it did find was a potential biomarker associated with SIDS risk. Using dried blood samples taken from about 600 infants in the few days following birth, the investigators measured the activity levels of butyrylcholinesterase (BChE), an enzyme which affects parasympathetic signaling through its actions on acetylcholine. The authors found that children who died from SIDS had lower BChE activity on average than either surviving children or children who had died of other causes.
Figure: BChE activity in non-SIDS and SIDS cases and controls. Non-SIDS cases represent infants who died of causes other than SIDS. Box plots illustrating interquartile ranges, outliers, mean (○), and median (−) values for each group. From Harrington, Hafid, & Waters, eBioMedicine, 2022.
In other words, low BChE activity appears to correlate with incidence of SIDS risk, but as I and many others have pointed out countless times, correlation is not causation. Even Dr. Harrington and her colleagues do not go so far as to claim discovery of the cause of SIDS, though they do speculate about possible causative mechanisms related to their BChE findings.
Still, even this speculation seems premature in light of the observation that, in this case, correlation is hardly even correlation: the association between BChE activity and SIDS risk may be significant (P = 0.0014), but the effect size is so small that it calls into question whether BChE would even have value as a biomarker of SIDS risk. With so much overlap in BChE between the SIDS and non-SIDS children, screening newborns by this metric certainly couldn’t provide any guarantees one way or the other. Children with relatively high BChE could still die of SIDS and vice versa. Thus, screening by such an imperfect marker may only serve to give parents a false sense of security or an unfounded sense of hopelessness.
Overblown reporting has misled the public
So what explains the mass misinterpretation of these findings by the public? Above all, the blame lies with irresponsible reporting by the popular press. Media outlets did not seem particularly concerned with the distinction between correlation and causation, instead spewing headlines claiming that the research had definitively identified the cause of SIDS. Some went further by announcing that the discovery might herald imminent breakthroughs in prevention and a future in which the threat of SIDS has been eliminated. Though several news outlets have since revised these headlines in the wake of backlash by the scientific and medical communities, the story had already caught the attention of much of the public.
The Dangers of Misinformation
Dr. Harrington’s study was not without its merits. Any incremental step toward understanding the underlying biology of SIDS is a commendable accomplishment and rightly offers much-needed solace to grieving parents, many of whom blame themselves for SIDS-attributed tragedies or believe there is no hope for their future children.
But to overstate the accomplishments of this research is dangerous. SIDS is a diagnosis of exclusion, meaning that it refers to any infant death that doesn’t fit any other known diagnoses. So even if the researchers had identified a cause of SIDS, it almost certainly wouldn’t be the only cause of SIDS, nor of infant mortality more generally. This nuance was lost by media reports announcing the discovery of “the” cause of SIDS, which many interpreted to mean that unexplained infant death is entirely predestined by biology. Such a deterministic view would imply that current recommendations for safe sleep practices have no effect on SIDS risk and could thus be abandoned. The number of social media posts promoting precisely that takeaway is horrifying.
“Scientists have found the cause of SIDS and it’s not belly sleeping. It’s entirely genetic,” read one tweet. “It didn’t matter if their baby slept on their back, front, side or upside down on their head. It would still have happened,” declared another.
I don’t blame tweeters for these misinterpretations; they’re trusting the statements of reputable news outlets and making logical conclusions based on what they’re hearing and reading. (The suggestion that SIDS can be prevented detracts even further from the importance of safe sleep practices.) Rebuttals of the overblown messaging have started popping up throughout social media, but when it comes to stories like this with high emotional appeal, it’s virtually impossible to put the toothpaste back in the proverbial tube.
Losing a child is any parent’s greatest fear. Whether popular media were angling hyperbole for the sake of readership or were just lazy in fact-checking, their reporting has taken cruel advantage of that parental fear. My hope is that researchers such as Dr. Harrington, who herself lost a son to SIDS decades ago, will indeed someday make SIDS a thing of the past. But until that time, I hope for more responsible media oversight, prioritizing safety over sensationalism.