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Introducing SIDS -

Sudden infant death syndrome (SIDS) is best defined as the "sudden, unexpected, and unexplained death of an apparently healthy baby."

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Cot death -

Sometimes known as "cot death," SIDS usually occurs while a baby is asleep, although it can also happen while they are awake.

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The numbers -

Devastating as it is, SIDS is rare and the risk of a baby dying from it is low. In the UK, for example, only around 200 babies die suddenly and unexpectedly each year.

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Exact cause -

The exact cause of SIDS is currently unknown, but it is believed there are a number of contributing factors. The leading theory is the Triple Risk Model.

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Triple Risk -

According to this model, for SIDS to occur, a baby must be at a particular stage in their development, as well as vulnerable to certain external stressors.

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'Vulnerable' -

Exactly what causes this ‘vulnerability’ is unknown. It may be caused by being born prematurely, having a low birth weight, or because of other reasons yet to be identified.

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Preventing SIDS -

For decades the focus has been on reducing exposure to external stressors, in a bid to bring down the number of SIDS cases.

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External stressors - External stressors known to increase the risk of SIDS include tobacco smoke, getting tangled in bedding, and minor illnesses or breathing obstructions.

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External stressors -

There is also an association between co-sleeping (sleeping with your baby on a bed, sofa, or chair) and the occurrence of SIDS.

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Decreasing numbers -

In the years after these risk factors were identified and parents received official recommendations for putting their baby to sleep, the number of infants dying of SIDS decreased.

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Numbers in 1990 -

In the US, for example, 155 in 100,000 infants were dying suddenly in their sleep from causes including SIDS in 1990.

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Numbers in 2000 -

By 2000 that number had fallen to 93 in every 100,000, and similar rates of decline were seen around the world.

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Plateau -

Over the last 20 years, however, we have seen that decline plateau. In 2020, for example, the rate was also 93 in every 100,000.

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Finding the cause and cure -

Sudden overnight deaths are largely still a mystery, and the search is very much on to find the cause and the cure.

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Making progress -

In December 2021, there was great excitement when a study was released that looked at activity levels of the blood enzyme butyrylcholinesterase (BChE).

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The role of BChE - BChE is an enzyme that plays a vital role in autonomic functions, such as sleeping and breathing.

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The study -

In the study, which looked at 700 babies including 26 who died from SIDS, the SIDS infants were found, on average, to have decreased BChE activity.

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Excitement in the field -

Following the publication of the study, there was a very enthusiastic press release, and headlines around the world claimed that the study’s authors had found the ‘cause’ of SIDS.

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More research needed -

Unfortunately, this is not the case. At this stage, a lower BChE level is only a biomarker. More research is needed to confirm whether it could be considered a cause.

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Caveat -

Furthermore, it is important to remember that it was the average level of BChE activity that differed between the SIDS babies and the controls; the ranges between the groups overlapped.

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Caveat -

This means that it could be difficult to determine exactly which level of BChE activity could indicate a problem, if any.

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What's next? -

Then there’s the question of what to do with the information, if indeed it is determined that a certain level of BChE activity is potentially problematic.

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Unnecessary scare -

We do not yet know what advice to give to parents whose children could be vulnerable. Coupled with the fact that the majority of children with this biomarker will not die of SIDS, there is the risk of scaring parents unnecessarily.

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Safe sleep -

In the meantime, therefore, healthcare providers continue to offer parents ‘safe sleep’ advice, i.e. tips on how to reduce the risk of SIDS.

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Safe sleep -

Most of the time, advice includes some positive actions (the ‘do’s’) and some things to avoid (the ‘don'ts).

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Example tips -

Parents are normally advised, for example, to put their baby to sleep on their back and with their feet touching the end of the cot, Moses basket, or pram.

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Example tips -

They are also advised to avoid smoking in the same room as their baby, and to avoid sleeping together with their baby on the same bed, sofa, or armchair.

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All in all -

Identifying these risk factors is not a silver bullet, however. In order to find a cure for SIDS, scientists first need to identify its cause.

Sources: (Nationwide Children's Hospital) (BBC) (NHS)

See also: What is cord blood, and who are the celebrity parents banking it?

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