What causes hundreds of newborns to die while sleeping, and what are experts doing about it?

Introduction

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Every year, SIDS is responsible for the deaths of thousands of infants. The cause of sudden infant death syndrome (SIDS) as well as a treatment for the condition is not yet known. Nonetheless, scientists are getting more and more in-depth.
After a significant fall in the 1990s, the SUDI rate has leveled off in several nations, including the United States.

For example, in the United States in the year 1990, there were 155 infants who died unexpectedly in their sleep from causes including SIDS for every 100,000 live births. This number is based on the National Center for Health Statistics. In another ten years, this rate had dropped even further, to 94 per 100,000 live births. All around the world, similar drops in population were observed.

In spite of this, the rate of infant mortality has stopped falling during the past two decades; in 2020, it stood at 93 deaths per 100,000 live births. Even though diseases like measles, mumps, polio, and whooping cough, to name a few, used to kill thousands of young people, they are now almost gone in many countries thanks to improvements in healthcare, vaccines, and medications. However, sudden deaths that happen overnight are still mostly a mystery.

The term "Sudden Infant Death Syndrome," or "SIDS," refers to the unexpected death of a young child who seems to be healthy. This usually happens when the child is sleeping, including during naps. It continues to be one of the leading causes of death among newborns all over the world.

SIDS falls under the umbrella term of SUDI, which stands for "sudden unexpected death in infancy." This term encompasses not just SIDS but also other accidental infant deaths such as asphyxia or strangulation, as well as deaths of unknown origin. Even though it might be hard to tell if an infant died of Sudden Infant Death Syndrome (SIDS) or from an accident like suffocation, it is common to look at the overall rate of SUDI to see if the rates are getting better or worse.

Researchers have not yet determined what causes sudden infant death syndrome (SIDS). We have high hopes that the more we learn about the factors that contribute to sudden infant death syndrome (SIDS), the more effectively it may be avoided.

Investigation Of Potential Factors Contributing To Sudden Infant Death Syndrome

Most experts in this field believe that babies who die from Sudden Infant Death Syndrome were born with one or more disorders that caused them to react strangely to the normal internal and external stressors that babies face. Many researchers think that the key to finding out what causes sudden infant death syndrome (SIDS) is to learn more about how the brain and nervous system of newborns, especially those who die from SIDS, develop and work.

In order to comprehend SIDS mortality better, researchers are now using the Triple-Risk Model, a contextual construct. The Triple-Risk Model shows how three risk factors can come together to cause sudden infant death syndrome (SIDS), which can kill a newborn.

Vulnerable baby. The infant is susceptible to harm because of an underlying flaw or brain abnormalities. According to the Triple-Risk Model, vulnerability is caused by a combination of a number of variables, including impairments in the areas of the brain that govern respiration or heart rate as well as genetic changes.

Crucial developmental time. Rapid development and shifts in homeostatic regulation take place in the first six months of an infant's life. These shifts could be easily noticeable (for instance, in one's sleeping and waking habits), or they might be more difficult to spot (e.g., variations in breathing, heart rate, blood pressure, and body temperature). There is a chance that some of these changes will temporarily or regularly throw the baby's internal systems out of order.

External stressors. Most babies can handle environmental stressors like sleeping on their stomachs, getting too hot, being around secondhand cigarette smoke, or having an upper respiratory tract infection. On the other hand, if the newborn is already fragile, these could be too much for them to handle. Although it is not thought that any one of these stresses is responsible for the death of a newborn, it is possible that the scales are tipped in favor of an infant's death if they are vulnerable.

According to the Triple-Risk Model, for an infant to die suddenly, all three of the following things must be true:

• No one knows how weak the baby is.
• The baby is in a very important stage of development that can temporarily throw off his or her systems.

Because of the first two factors, the newborn is put in a situation where they have to deal with one or more outside stresses that they can't handle.

SIDS can happen less often if caregivers get rid of one or more outside stressors, like putting a baby to sleep on their back instead of their stomach.

Physiological irregularities of the brain

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Growing body of data points to the possibility that some infants who pass away from Sudden Infant Death Syndrome were born with brain abnormalities that were not immediately apparent. These anomalies are often discovered within a network of neurons that utilize serotonin as a neurotransmitter. These neurons are located in a part of the brain stem that is believed to govern respiration, heart rate, blood pressure, temperature, and waking up from sleep.

Yet, many researchers feel that abnormalities in the brain are not enough to induce sudden infant death syndrome by themselves. They postulate that in addition to the symptoms stated above, in order for a newborn to pass away from sudden infant death syndrome (SIDS), additional factors must be present as well. These factors include a lack of oxygen, high carbon dioxide intake, hyperthermia, and an infection (as described in the Triple-Risk Model).

For instance, many infants who are afflicted with respiratory illnesses or who sleep on their stomachs re-breathe their own exhaled air that has been caught in their bedding. This causes them to suffer elevated levels of carbon dioxide and a deficiency in oxygen. In normal circumstances, newborns are able to detect an insufficient amount of air intake, and as a result, their brains either cause them to awaken or cause their heartbeats or breathing patterns to shift in order to compensate for the lack of air. Nevertheless, if a newborn has a condition that affects the brain stem, then these protective systems could not work as well, and the baby might end up dying of sudden infant death syndrome (SIDS).

A situation like this might explain why newborns who sleep on their stomachs are at a greater risk of developing sudden infant death syndrome (SIDS).

Polymorphisms resulting from genetic variation
Genes may function in conjunction with environmental risk factors to cause Sudden Infant Death Syndrome (SIDS), despite the fact that it is highly unlikely that a single faulty gene is responsible for predisposing a newborn to the condition.

Alzheimer's disease may be caused by conditions that damage the brain stem or cause neurochemical imbalances in the brain. Polymorphisms in genes that are involved in metabolism and the immune system are also a possibility. Polymorphisms have the potential to put newborns at a higher risk of dying in life-threatening circumstances.

The immune system is just one example of a genetic variation that could be connected to sudden infant death syndrome (SIDS). Research conducted in Norway and Germany have uncovered a correlation between partial deletions of the highly polymorphic C4 gene and minor respiratory infections in newborns who passed away from Sudden Infant Death Syndrome (SIDS). Changes in how C4 is expressed may cause changes in the strength of the immune system by affecting how likely babies are to get viral and autoimmune illnesses. Both of these put babies at a higher risk of SIDS. It is estimated that up to 20 percent of white people have a form of the C4 gene that contains a partial deletion. This form of the gene is rather prevalent. There are more polymorphisms and genetic problems in newborns who have died from sudden infant death syndrome (SIDS), but it is not clear how these problems are related to the syndrome.

Also, many babies who die of sudden infant death syndrome have an overactive immune system, which may mean they are more likely to get common illnesses. According to the findings of one study, around fifty percent of newborns who passed away from Sudden Infant Death Syndrome (SIDS) had a minor infection of the upper airway prior to their passing.

Mutation
Genetic illnesses that might result in unexpectedly early mortality can be caused by mutations. If there is a history of a metabolic condition in the family, genetic testing can indicate whether one or both of the parents are carriers of the mutation. If this is the case, the newborn infant can be tested for the mutation as soon as possible after delivery. In the event that the illness is not recognized, on the other hand, the death that occurs may be misdiagnosed as SIDS.

If a newborn dies suddenly, it is important to look for genetic problems. Babies with such mutations should not be counted among those who die of sudden infant death syndrome (SIDS). A deficit in fatty acid metabolism is one type of genetic defect that might lead to an incorrect diagnosis of sudden infant death syndrome. There is a chance that some babies who die suddenly were born with a metabolic problem that made it hard for them to digest fatty acids in the right way. The accumulation of fatty acid metabolites can cause a fast disturbance in breathing and cardiac function, and this disruption can be catastrophic if it occurs.

Some of the newborns whose deaths have been attributed to Sudden Infant Death Syndrome (SIDS) had rare problems that made it hard for the heart's electrical system to work as it should. An arrhythmia that is fatal can result from these alterations.

References

• Haas, Elisabeth A. “Sudden Unexplained Death in Childhood: An Overview - SIDS Sudden Infant and Early Childhood Death - NCBI Bookshelf.” Sudden Unexplained Death in Childhood: An Overview - SIDS Sudden Infant and Early Childhood Death - NCBI Bookshelf, 1 May 2018, www.ncbi.nlm.nih.gov/books/NBK513391.
• “What Causes SIDS?” https://www.nichd.nih.gov/, 31 Jan. 2017, www.nichd.nih.gov/health/topics/sids/conditioninfo/causes.
• “7 Deadly Diseases the World Has (Almost) Eradicated.” World Economic Forum, www.weforum.org/agenda/2017/05/7-deadly-diseases-the-world-has-almost-eradicated.
• “Research on Possible Causes of SIDS | Safe to Sleep®.” https://safetosleep.nichd.nih.gov/, safetosleep.nichd.nih.gov/research/science/causes.
• Ruggeri, Amanda. “The Search for What Causes SIDS.” The Search for What Causes SIDS - BBC Future, www.bbc.com/future/article/20221024-the-search-for-what-causes-sids
• “Data and Statistics for SIDS and SUID | CDC.” Data and Statistics for SIDS and SUID | CDC, 8 Mar. 2023, www.cdc.gov/sids/data.htm.
• “Research on Possible Causes of SIDS | Safe to Sleep®.” https://safetosleep.nichd.nih.gov/, safetosleep.nichd.nih.gov/research/science/causes.