All Topics  
Sudden infant death syndrome

 

   Email Print
   Bookmark   Link






 

Sudden infant death syndrome



 
 
Sudden infant death syndrome (SIDS) is a syndrome marked by the symptoms of sudden and unexplained death of an apparently healthy infant
Infant

An infant or baby is the term used to refer to the young offspring of humans....
 aged one month to one year. The term cot death is often used in the United Kingdom
United Kingdom

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom , the UK or Britain,is a sovereign state located off the northwestern coast of continental Europe....
, Ireland
Ireland

Ireland is the List of islands by area in Europe, and the twentieth-largest island in the world. It lies to the north-west of continental Europe and is surrounded by hundreds of islands and islet....
, Australia
Australia

Australia, officially the Commonwealth of Australia, is a country in the southern hemisphere comprising the Australia of the world's smallest continent, the major island of Tasmania, and numerous list of islands of Australia in the Indian Ocean and Pacific Oceans....
 and New Zealand
New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses , and numerous Islands of New Zealand, most notably Stewart Island/Rakiura and the Chatham Islands....
, while crib death is sometimes used in North America
North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
.

cally the infant is found dead after having been put to bed, and exhibits no signs of having suffered.

SIDS is a diagnosis of exclusion.






Discussion
Ask a question about 'Sudden infant death syndrome'
Start a new discussion about 'Sudden infant death syndrome'
Answer questions from other users
Full Discussion Forum



Encyclopedia


Sudden infant death syndrome (SIDS) is a syndrome marked by the symptoms of sudden and unexplained death of an apparently healthy infant
Infant

An infant or baby is the term used to refer to the young offspring of humans....
 aged one month to one year. The term cot death is often used in the United Kingdom
United Kingdom

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom , the UK or Britain,is a sovereign state located off the northwestern coast of continental Europe....
, Ireland
Ireland

Ireland is the List of islands by area in Europe, and the twentieth-largest island in the world. It lies to the north-west of continental Europe and is surrounded by hundreds of islands and islet....
, Australia
Australia

Australia, officially the Commonwealth of Australia, is a country in the southern hemisphere comprising the Australia of the world's smallest continent, the major island of Tasmania, and numerous list of islands of Australia in the Indian Ocean and Pacific Oceans....
 and New Zealand
New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses , and numerous Islands of New Zealand, most notably Stewart Island/Rakiura and the Chatham Islands....
, while crib death is sometimes used in North America
North America

North America is the northern continent of the Americas, situated in the Earth's northern hemisphere and almost totally in the western hemisphere....
.

Overview

Typically the infant is found dead after having been put to bed, and exhibits no signs of having suffered.

SIDS is a diagnosis of exclusion. It can only be applied to an infant whose death is sudden and unexpected, and remains unexplained after the performance of an adequate postmortem investigation including

  1. an autopsy;
  2. investigation of the scene and circumstances of the death;
  3. exploration of the medical history
    Medical history

    The medical history or anamnesis J - jaundice T - tuberculosis H - hypertension & heart disease R - rheumatic fever...
     of the infant and family.


SIDS is responsible for roughly 1 death per 2,000 births in the U.S. It is responsible for far fewer deaths than congenital disorders and disorders related to short gestation, though it is the leading cause of death in healthy infants after one month of age.

SIDS deaths in the U.S. decreased from 4,895 in 1992 to 2,247 in 2004. But, during a similar time period, 1989 to 2004, SIDS being listed as the cause of death for sudden infant death (SID) decreased from 80% to 55%. According to Dr. John Kattwinkel, chairman of the Center for Disease Control (CDC) Special Task Force on SIDS "A lot of us are concerned that the rate (of SIDS) isn't decreasing significantly, but that a lot of it is just code shifting”.

SIDS Back To Sleep Campaign: History and Theory


In 1987 the Netherlands started a campaign advising parents to place their newborn infants to sleep on their backs (supine position) instead of their stomachs (prone position). This was followed by infant supine sleep position campaigns in the United Kingdom, New Zealand, and Australia in 1991, the U.S. and Sweden in 1992, and Canada in 1993.

This advice was based on physiological evidence which shows that infants who sleep on their back have lower arousal thresholds and less Slow-Wave Sleep
Slow-wave sleep

Slow-wave sleep , often referred to as deep sleep, consists of stages three and four of non-rapid eye movement sleep, according to the Rechtschaffen & Kales standard of 1968....
 (SWS) compared to infants who sleep on their stomachs. In human infants sleep develops rapidly during early development. This development includes an increase in non-rapid eye movement sleep (NREM sleep) which is also called Quiet Sleep (QS) during the first 12 months of life in association with a decrease in rapid eye movement sleep (REM sleep) which is also known as Active Sleep (AS). In addition, slow wave sleep (SWS) which consists of Stage 3 and Stage 4 NREM sleep appears at 2 months of age. and it is theorized that some infants have a brain-stem defect which increases their risk of being unable to arouse from SWS (also called Deep Sleep) and therefore have an increased risk of SIDS due to their increased inability to arouse from SWS. In a currently used model that explains the process in which slow wave sleep is involved in memory consolidation
Memory consolidation

Memory consolidation, broadly defined, is the process by which recent memory are crystallised into long-term memory. The term "consolidation" is used to refer to different levels of organization:...
 the hippocampus
Hippocampus

The hippocampus is a brain structure located inside the medial temporal lobe of the cerebral cortex, and therefore is part of the telencephalon ....
 acts as a temporary storage facility for new memories which are then transferred to the neocortex
Neocortex

The neocortex is a part of the brain of mammals. It is the outer layer of the cerebral hemispheres, and made up of six layers, labelled I to VI ....
 during slow wave sleep (SWS).

Studies have shown that preterm infants, full-term infants, and older infants have greater time periods of quiet sleep and also decreased time awake when they are positioned to sleep on their stomachs. In both human infants and rats, arousal thresholds have been shown to be at higher levels in the Electroencephalography
Electroencephalography

Electroencephalography is the recording of electrical activity along the scalp produced by the firing of neurons within the brain. In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, usually 20-40 minutes, as recorded from multiple electrodes placed on the scalp....
 (EEG) during Slow-wave sleep
Slow-wave sleep

Slow-wave sleep , often referred to as deep sleep, consists of stages three and four of non-rapid eye movement sleep, according to the Rechtschaffen & Kales standard of 1968....
.

In 1992, a SIDS risk reduction strategy based upon lowering arousal thresholds during SWS was implemented by the American Academy of Pediatrics (AAP) which began recommending that healthy infants be positioned to sleep on their back (supine position) or side (lateral position), instead of their stomach (prone position), when being placed down for sleep. In 1994, a number of organizations in the United States combined to further communicate these non-prone sleep position recommendations and this became formally known as the “Back To Sleep” campaign. In 1996, the AAP further refined its sleep position recommendation by stating that infants should only be placed to sleep in the supine position and not in the prone or lateral positions.

In 1992, the first National Infant Sleep Position (NISP) Household Survey was conducted to determine the usual position in which U.S. mothers placed their babies to sleep: (1) Lateral (side); (2) Prone (stomach); (3) Supine (back); (4) Other; (5) No Usual Position. According to the 1992 NISP survey, 13.0% of U.S. infants were positioned in the supine position for sleep. According to the 2006 NISP survey 75.7% of infants were positioned in the supine position to sleep.

Since 1998 there have been several studies published which report that infants placed to sleep in the supine position lag in motor skills, social skills, and cognitive ability development when compared to infants who sleep in the prone position. In the 1998 article entitled “Effects of Sleep Position on Infant Motor Development.” [14] by Davis, Moon, Sachs, and Ottolini, the authors state “We found that sleep position significantly impacts early motor development.” The prone (stomach) sleeping infants in this study slept an average of 225.2 hours (8.3%) more in their first 6 months of life than the supine (back) sleeping infants.

In the 1998 article entitled “Does the Supine Sleeping Position Have Any Adverse Effects on the Child? II. Development in the First 18 Months” by Dewey, Fleming, Golding, and the ALSPAC Study Team the objective of the study was “To assess whether the recommendations that infants sleep supine could have adverse consequences on their motor and mental development.” They used the Denver Developmental Screening Test (DDST) and studied infants at 6 and 18 months. According to the study, at 6 months of age, the infants who were placed to sleep in the prone position had statistically significant higher social skills scores, gross motor scores, and total development scores than those infants who were put to sleep in the supine position. In addition, the total development scores of prone sleeping infants were still higher than supine sleeping infants at 18 months of age but were no longer statistically significant. In the 2005 article entitled “Influence of supine sleep positioning on early motor milestone acquisition” by Majnemer and Barr they used the Alberta Infant Motor Scale Scores (AIMS Scores) to analyze the impact of infant sleep position. They reported that “Typically developing infants who were sleep-positioned in supine had delayed motor development by age 6 months, and this was significantly associated with limited exposure to awake prone positioning.” But, the authors also note that awake prone (stomach) positioning is associated with prone (stomach) sleeping. No studies have been conducted which compare supine sleeping infants who have regular awake prone positioning (tummy time) to prone sleeping infants who have regular awake prone positioning (tummy time).

Placing infants on their stomachs while they are awake (tummy time) has been recommended to offset the motor skills delays associated with the back sleep position but positioning the infant on their stomach while awake will not impact the amount of slow wave sleep since tummy time only occurs when an infant is awake.

Undiagnosed conditions


Some conditions that may be undiagnosed and thus result in a diagnosis of SIDS include

  • medium-chain acyl-coenzyme A dehydrogenase deficiency
    Medium-chain acyl-coenzyme A dehydrogenase deficiency

    Medium-chain acyl-coenzyme A dehydrogenase deficiency is a fatty acid oxidation disorder associated with inborn error of metabolism. It is due to defects in the enzyme complex known as medium-chain acyl dehydrogenase and reduced activity of this complex....
     (MCAD deficiency);
  • infant botulism
    Botulism

    Botulism also known as "Botulinus Intoxication," is a rare but serious paralytic illness caused by botulin toxin. The toxin is produced by the bacteria Clostridium botulinum....
    ;
  • long QT syndrome
    Long QT syndrome

    The long QT syndrome is a rare congenital heart condition with delayed repolarization following depolarization of the heart, associated with fainting due to left ventricle cardiac arrhythmia, possibly of type torsade de pointes, which can deteriorate into ventricular fibrillation and ultimately Sudden cardiac death....
    ;
  • infections with the bacterium Helicobacter pylori
    Helicobacter pylori

    Helicobacter pylori is a Gram-negative, microaerophile bacterium that inhabits various areas of the stomach and duodenum. It causes a chronic low-level inflammation of the stomach lining and is strongly linked to the development of duodenal and gastric peptic ulcers and stomach cancer bacteria....
    ;
  • shaken baby syndrome
    Shaken baby syndrome

    Shaken baby syndrome is a form of child abuse that occurs when an abuser violently shakes an infant or small child, creating a whiplash -type motion that causes acceleration-deceleration injuries....
     and other forms of child abuse
    Child abuse

    Child abuse is the physical abuse, psychological abuse or child sexual abuse maltreatment of children. The Centers for Disease Control and Prevention defines child maltreatment as any act or series of acts or commission or omission by a parent or other caregiver that results in harm, potential for harm, or threat of harm to a child....
    .
  • foul play
    Foul Play

    Foul Play is a 1978 in film film by Colin Higgins starring Goldie Hawn and Chevy Chase. They are supported by Burgess Meredith, Brian Dennehy, Billy Barty and Dudley Moore in one of his first American feature film appearances....


Risk factors


Very little is certain about the possible causes of SIDS, and there is no proven method for prevention. Although studies have identified risk factors for SIDS, such as putting infants to bed on their stomachs, there has been little understanding of the syndrome's biological cause or causes. The frequency of SIDS appears to be a strong function of infant sex and the age, ethnicity, and the education and socio-economic status of the parents.

According to a study published in October 2007 in the Journal of the American Medical Association, babies who die of SIDS have abnormalities in the brain stem (the medulla oblongata
Medulla oblongata

The medulla oblongata is the lower portion of the brainstem. It deals with Autonomic nervous system functions, such as breathing and blood pressure....
), which helps control functions like breathing, blood pressure and arousal. Researchers examined the medullae of 31 babies who had died of SIDS and 10 who had died from other causes. Compared to babies who died of other causes, the SIDS babies had over twice as many serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
-releasing neurons originating in the medulla, but fewer serotonin binding sites. They also found abnormalities that appear to affect the ability to use and recycle serotonin, which is responsible for regulating mood as well as vital body functions. According to the National Institutes of Health, which funded the study, this finding is the strongest evidence to date that structural differences in a specific part of the brain may contribute to the risk of SIDS.

In a British study released May 29, 2008 researchers discovered that the common bacterial infections Staphylococcus aureus
Staphylococcus aureus

Staphylococcus aureus is the most common cause of staph infections. It is a spherical Bacteria, frequently found in the nose and skin of a person....
 (staph) and Escherichia coli
Escherichia coli

'Escherichia coli' , is a Gram negative bacterium that is commonly found in the lower gastrointestinal tract of warm-blooded animals. Most E....
 (E. coli) appear to be the cause of some cases of Sudden Infant Death Syndrome. Both bacteria were present at greater than usual concentrations in infants who died from SIDS. SIDS cases peak between eight and ten weeks after birth, which is also the time frame in which the antibodies
Antibody

Antibodies are gamma globulin proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacterium and viruses....
 that were passed along from mother to child are starting to disappear and babies have not yet made their own antibodies.

Listed below are several factors associated with increased probability of the syndrome based on information available prior to this recent study.

Prenatal risks

  • maternal nicotine use (tobacco or nicotine patch)
  • inadequate prenatal care
  • inadequate prenatal nutrition
    Nutrition

    Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with good nutrition....
  • use of heroin
    Heroin

    Heroin is a opioid synthesized from morphine, a derivative of the opium poppy. It is the 3,6-acetate ester of morphine . The white crystalline form is commonly the hydrochloride salt diacetylmorphine hydrochloride, however heroin Freebase may also appear as a white powder....
  • subsequent births less than one year apart
  • alcohol
    Alcohol

    In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
     use
  • being overweight
  • Teen pregnancy (the more babies a teen mother has, the greater the risk)
  • infant's sex (61% of SIDS cases occur in males)


Post-natal risks

  • low birth weight (especially less than 1.5 kg (~3.3 lb))
  • exposure to tobacco
    Tobacco

    Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is used in some medicines....
     smoke
  • prone sleep position (lying on the stomach, see sleep positioning below)
  • not breastfeeding
    Breastfeeding

    Breastfeeding is the feeding of an infant or young child with breast milk directly from human breasts rather than from a baby bottle or other container....
  • elevated room temperature
  • excess bedding, clothing, soft sleep surface and stuffed animals
  • infant's age (incidence rises from zero at birth, is highest from two to four months, and declines towards zero at one year)
  • premature birth (increases risk of SIDS death by 50 times)


Risk reduction for SIDS


Though SIDS cannot be prevented, parents of infants are encouraged to take several precautions in order to reduce the likelihood of SIDS.

Environment


Sleep positioning
Sleeping on the back has been recommended by (among others) the American Academy of Pediatrics
American Academy of Pediatrics

The American Academy of Pediatrics was founded in 1930 and now has 60,000 primary care pediatricians, pediatric medical subspecialists and pediatric surgical specialists as members....
 (starting in 1992) to avoid SIDS, with the catchphrases "Back To Bed" and "Back to Sleep
Back to Sleep

"Back to Sleep" is an initiative backed by the National Institute of Child Health and Human Development at the National Institutes of Health to encourage parents to have their infants sleep on their backs to reduce the risk of Sudden Infant Death Syndrome, or SIDS....
." The incidence of SIDS has fallen sharply in a number of countries in which the back to bed recommendation has been widely adopted, such as the US and New Zealand. However, the absolute incidence of SIDS prior to the Back to Sleep Campaign was already low in the US.

Among the theories supporting the Back to Sleep recommendation is the idea that small infants with little or no control of their heads may, while face down, inhale their exhaled breath (high in carbon dioxide) or smother themselves on their bedding—the brain-stem anomaly research (above) suggests that babies with that particular genetic makeup do not react "normally" by moving away from the pooled CO2, and thus smother. Another theory is that babies sleep more soundly when placed on their stomachs, and are unable to rouse themselves when they have an incidence of sleep apnea
Sleep apnea

Sleep apnea is a sleep disorder characterized by pauses in breathing during sleep. Each episode, called an apnea , lasts long enough so that one or more breaths are missed, and such episodes occur repeatedly throughout sleep....
, which is thought to be common in infants.

Arguments against infant back-sleeping include concerns that an infant could choke on fluids it brings up. Hospital staff commonly place newborns on their side, although they advise parents to place their infants on their backs after going home from the hospital.

Other concerns raised about the Back to Sleep Campaign have included the possible increased risk of positional facial and head deformities (see positional plagiocephaly
Positional plagiocephaly

Positional plagiocephaly, also known as deformational plagiocephaly or flathead syndrome, is a condition most commonly found in infants and is characterized by a flat spot on the back or one side of the head caused by remaining in one position for too long....
), possible interference with development of good sleep habits (which in turn may have other bad effects), and possible interference with motor skills development (as infants delay attempts to lift their heads, crawl, etc.).

Breastfeeding
A 2003 study published in Pediatrics
Pediatrics (journal)

Pediatrics is an official peer-reviewed journal of the American Academy of Pediatrics. In the inaugural January 1948 issue of PEDIATRICS, the journal's first editor, Hugh McCulloch, articulated the journal's vision: "The content of the journal is......
, which investigated racial disparities in infant mortality in Chicago, found that previously or currently breastfeeding
Breastfeeding

Breastfeeding is the feeding of an infant or young child with breast milk directly from human breasts rather than from a baby bottle or other container....
 infants in the study had 1/5 the rate of SIDS compared with non-breastfed infants, but that "it became nonsignificant in the multivariate model that included the other environmental factors". These results are consistent with most published reports and suggest that other factors associated with breastfeeding, rather than breastfeeding itself, are protective."

Co-sleeping

One approach to lowering SIDS rates is limiting co-sleeping
Co-sleeping

Co-sleeping, also called the family bed, is a practice in which babies and young children sleep with one or both parenting, as opposed to a separate infant bed....
. A 2005 policy statement by the American Academy of Pediatrics
American Academy of Pediatrics

The American Academy of Pediatrics was founded in 1930 and now has 60,000 primary care pediatricians, pediatric medical subspecialists and pediatric surgical specialists as members....
 on sleep environment and the risk of SIDS found co-sleeping and bed sharing to be unsafe. However, some data has suggested that almost all SIDS deaths in adult beds occur when other prevention methods, such as placing infants on their backs, are not used. Co-sleeping studied in the West has been present mostly in poorer families where other risk factors are present. while co-sleeping in other cultures such as in China is more prevalent and is done in combination with practices such as sleeping children on their back, correlating with a significantly lower rate of SIDS than the West. There are also evolutionary theories as to why co-sleeping would be healthier for infants than sleeping alone. Further studies have suggested that factors associated with safe co-sleeping such as enhanced infant arousals are responsible for a positive contribution to SIDS prevention. Co-sleeping is made safer with the use of a bedside "co-sleeper", rather than having the infant sleep in your bed. Adult beds are unsafe for infants. The safest place for infants to sleep is a place with bedding made specifically for infants.

Secondhand smoke reduction
According to the U.S. Surgeon General’s Report, secondhand smoke is connected to SIDS. Infants who die from SIDS tend to have higher concentrations of nicotine
Nicotine

Nicotine is an alkaloid found in the nightshade family of plants which constitutes approximately 0.6?3.0% of dry weight of tobacco, with biosynthesis taking place in the roots, and accumulating in the leaves....
 and cotinine
Cotinine

Cotinine is a metabolite of nicotine. The word 'cotinine' is an anagram of 'nicotine'. It is used to measure the grade of tobacco smoking, but might also improve mental function....
 (a biological marker for secondhand smoke exposure) in their lungs than those who die from other causes. Infants exposed to secondhand smoke after birth are also at a greater risk of SIDS. Parents who smoke can significantly reduce their children's risk of SIDS by either quitting or smoking only outside and leaving their house completely smoke-free.

The maternal pregnancy smoking rate decreased by 38% between 1990 and 2002.

Sleeping area


Bedding

To prevent SIDS, many families use firm mattresses with tight-fitting sheets in cribs or bassinets. The families do not allow pillows, stuffed animals, or fluffy bedding in the cribs. In cold weather, the families dress the infants warmly in well-fitted clothing.

Infants' blankets should also not be placed over their heads. It has been recommended that the infants are only covered up to their chest with their arms exposed. This will help eliminate the chances of the infant moving the blanket over their head.

Sleep sacks
In colder environments where bedding is required to maintain a baby's body temperature, the use of a "baby sleep bag
Sleeping bag (infant)

An infant sleeping bag is a bag-like clothing or coveringworn by infants for sleeping. Infant sleeping bags differ fromregular sleeping bags in design and purpose, being designed primarily for...
" or "sleep sack" is becoming more popular. This is a soft bag with holes for the baby's arms and head. A zipper allows the bag to be closed around the baby. A study published in the
European Journal of Pediatrics in August 1998 has shown the protective effects of a sleep sack as reducing the incidence of turning from back to front during sleep, reinforcing putting a baby to sleep on its back for placement into the sleep sack and preventing bedding from coming up over the face which leads to increased temperature and carbon dioxide rebreathing. They conclude in their study "The use of a sleeping-sack should be particularly promoted for infants with a low birth weight." The AAP also recommends them as a type of bedding that warms the baby without covering its head.

Pacifiers

According to a 2005 meta-analysis, most studies favor pacifier use. According to the American Academy of Pediatrics
American Academy of Pediatrics

The American Academy of Pediatrics was founded in 1930 and now has 60,000 primary care pediatricians, pediatric medical subspecialists and pediatric surgical specialists as members....
 (AAP), pacifier use seems to reduce the risk of SIDS, although the mechanism by which this happens is unclear. SIDS experts and policy makers haven't recommended the use of pacifiers to reduce the risk of SIDS because of several problems associated to pacifier use, like increased risk of otitis, gastrointestinal infections and oral colonization with Candida species.

A 2005 study indicated that use of a pacifier
Pacifier

A pacifier is a rubber, plastic, or silicone nipple given to an infant or other young child to suck upon. In its standard appearance it has a teat, mouth shield, and handle....
 is associated with up to a 90% reduction in the risk of SIDS depending on the ambiental factors, and it reduced the effect of other risk factors. It has been speculated that the raised surface of the pacifier holds the infant's face away from the mattress, reducing the risk of suffocation. If a postmortem investigation does not occur or is insufficient, a suffocated baby may be misdiagnosed with SIDS.

Air circulation with fan use
According to a study of nearly 500 babies published the October 2008 Archives of Pediatrics & Adolescent Medicine
Archives of Pediatrics & Adolescent Medicine

The Archives of Pediatrics & Adolescent Medicine is a monthly professional medical journal published by the American Medical Association. Archives of Pediatrics & Adolescent Medicine publishes original, peer-reviewed clinical and basic research articles covering all aspects of pediatric primary care....
, using a fan to circulate air correlates with a lower risk of sudden infant death syndrome. Researchers took into account other risk factors and found that fan use was associated with a 72% lower risk of SIDS. Only 3% of the babies who died had a fan on in the room during their last sleep, the mothers reported. That compared to 12% of the babies who lived. Using a fan reduced risk most for babies in poor sleeping environments. Author De-Kun li said that "the baby's sleeping environment really matters" and that "this seems to suggest that by improving room ventilation we can further reduce risk."

Bumper pads

Bumper pads may be a contributing factor in SIDS deaths and should be removed. Health Canada
Health Canada

Health Canada is the Ministry of the government of Canada with responsibility for national public health.The current Minister of Health is Leona Aglukkaq, a Conservative Member of Parliament appointed to the position by Prime Minister of Canada Stephen Harper....
, the Canadian government's health department, issued an advisory recommending against the use of bumper pads, stating:

Speculated associations


A number of theoretical causes have been proposed as a trigger for SIDS, but many of them are unproven or have not been thoroughly studied and peer-reviewed.

Mattress bugs

A 2002 study hypothesized that bugs feeding on baby vomit and dust could be fatal for small children, creating 'supertoxins' which spur the baby's body into overreacting, leading to anaphylactic shock.

Brain disorder

A recently published research article in the Journal of the American Medical Association
Journal of the American Medical Association

JAMA: The Journal of the American Medical Association is an international peer-reviewed general medical journal, published 48 times per year by the American Medical Association....
 showed evidence that cells in the brainstem fail to develop receptors for Serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
 in the womb. This abnormality continues until after birth, supposedly until the end of their first year. This would account for there being few to no SIDS deaths after the first year of infancy and the reason the risk is more for premature infants. The SIDS Alliance/First Candle has posted a message about this along with a link to the abstract on their website (www.firstcandle.com), which can be accessed from the front page

Vitamin C


According to a 1993 article in
Journal of Orthomolecular Medicine
Journal of Orthomolecular Medicine

The Journal of Orthomolecular Medicine , founded by Abram Hoffer in 1967, publishes studies in nutritional and orthomolecular medicine. There is controversy surrounding the journal, as the validity of the field of orthomolecular medicine is not widely accepted by the mainstream pharmaceutical based medical industry....
, Australian medical doctor Archie Kalokerinos
Archie Kalokerinos

Archivides "Archie" Kalokerinos is an Australian physician. In 2000 he was awarded the title Greek Australian of the Century by the Melbourne-based Greek newspaper Neos Kosmos....
 performed research showing that high doses of vitamin C eliminates SIDS. As SIDS was shown to be caused solely by vitamin deficiency, the article stated that it was no longer a syndrome
Syndrome

In medicine and psychology, the term syndrome refers to the association of several clinically recognizable features, sign , symptoms , phenomena or characteristics that often occur together, so that the presence of one feature alerts the physician to the presence of the others....
, and that the proper disease name is now SID. As of January 2007, the
Journal of Orthomolecular Medicine was not included among journals selected by the U.S. National Library of Medicine
United States National Library of Medicine

The United States National Library of Medicine , operated by the United States federal government, is the world's largest medical library. The collections of the National Library of Medicine include more than seven million books, journals, technical reports, manuscripts, microfilms, photographs, and images on medicine and related science...
 for inclusion in their Medline
MEDLINE

MEDLINE is a literature Bibliographic database of life sciences and biomedical information. It includes medicine, nursing, pharmacy, dentistry, veterinary medicine, and health care....
 database.

Toxic gases


In 1989, a controversial piece of research by UK Scientist Barry Richardson claimed that all cot deaths were the result of toxic nerve gases being produced through the action of fungus
Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
 in mattresses on compounds of phosphorus
Phosphorus

Phosphorus is the chemical element that has the symbol P and atomic number 15. The name comes from the and . A Valency nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate minerals....
, arsenic
Arsenic

Arsenic is a well-known chemical element that has the symbol As and atomic number 33. Arsenic was first documented by Albertus Magnus in 1250....
 and antimony
Antimony

Antimony is a chemical element with the symbol Sb and atomic number 51. A metalloid, antimony has four allotropy forms. The stable form of antimony is a blue-white metalloid....
. These chemicals are frequently used to make mattresses fire-retardant.

A major plank in this explanation is the widely-observed phenomenon that the risk of cot death rises from one sibling to the next. Richardson claims that the cause is that parents are more likely to buy new bedding for their first child, and to re-use that bedding for later children. The more frequently used the bedding is, the more chance there will be that fungus has become resident in the material; thus, a higher chance of cot death. A paper by Peter Fleming and Peter Blair references evidence from other studies that both supports and refutes the increasing occurrence of SIDS with mattress sharing and suggests that this is still inconclusive.

In 1994, the New Zealand
New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses , and numerous Islands of New Zealand, most notably Stewart Island/Rakiura and the Chatham Islands....
 government, under the advice of Dr. Jim Sprott, issued advice recommending new parents to either buy bedding free of the toxic compounds or to wrap the mattresses in a barrier film to prevent the escape of the gases. Dr. Sprott claims that no case of cot death has ever been traced back to a properly manufactured or wrapped mattress.

However, a final report of The Expert Group to Investigate Cot Death Theories: Toxic Gas Hypothesis, published in May 1998, concluded that "there was no evidence to substantiate the toxic gas hypothesis that antimony- and phosphorus-containing compounds used as fire retardants in PVC and other cot mattress materials are a cause of SIDS. Neither was there any evidence to believe that these chemicals could pose any other health risk to infants." The report also states that "in normal cot-like conditions it is not possible to generate toxic gas from antimony in mattresses" and "babies have also been found to die on wrapped mattresses." Dr. Sprott's website, however, claims that the study does not actually refute his theory:

Contrary to media publicity, the 1998 UK Limerick Report did not disprove the toxic gas theory—as a highly qualified environmental scientist has stated in the New Zealand Medical Journal. In fact, the Limerick Committee's experiments proved the fungal generation of toxic gases (forms of stibine and arsine) from cot mattress materials.


According to Dr. Sprott, as of 2006, the New Zealand government has not reported any SIDS deaths when babies have slept on mattresses wrapped according to his method. While the Limerick report claims that babies have been found to die on wrapped mattresses, Dr. Sprott argues that a chemical analysis of the bedding should be performed. He additionally claims that this part of the report was flawed:

In February 2000 Dr Peter Fleming (a co-author of the Limerick Report and principal author of the UK CESDI Report) conceded that the claim that three babies in the United Kingdom had died of cot death on polythene-covered mattresses could not be substantiated.


Central Respiratory Pattern Deficiency


There is ongoing research in the pediatric/neonatal community that has begun to associate apnea-like breathing cessations in animal models with unusual neural architecture or signal transduction in central pattern generator circuits including the pre-Bötzinger complex. It is possible that irregularities in neurotransmitter release (such as GABA
Gabâ

Gab? or gabaa, for the Cebuano people , is the concept of a non-human and non-divine, imminent Retributive justice. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions....
, adenosine
Adenosine

Adenosine is a nucleoside composed of a molecule of adenine attached to a ribose sugar molecule moiety via a ?-N9-glycosidic bond....
, and NMDA
NMDA

NMDA is an amino acid derivative acting as a specific agonist at the NMDA receptor, and therefore mimics the action of the neurotransmitter glutamate on that receptor....
) or deficiencies in their associated receptors (including both GABAA, GABAB subtypes and NMDA-glutamate receptors) are linked to incomplete prenatal development as is evident in pre-term infants.

Genetic factors are also being studied with several rat and mouse knockouts.

Upper cervical spinal cord injury as a result of birth trauma


During birth, if the infant's head is traumatically turned side to side, upper cervical spinal injury can result. Difficulty breathing is a classic sign of upper spinal cord and brain-stem injury. When infants with undiagnosed upper cervical spinal cord injury are continually placed on their stomach for sleep, they are forced to turn their head to the side to breathe. This is hypothesised to aggravate and prolong the spinal cord injury sustained during birth, preventing proper healing and ultimately leading to fatal breathing difficulty.

Gender

There is a consistent 50% male excess in SIDS per 1000 live births of each sex. Given a 5% male excess birth rate (105 male to 100 female live births) there appear to be 3.15 male SIDS per 2 female SIDS for a male fraction of 0.61. The X-linkage
Sex linkage

Sex linkage is the phenotype expression of an allele that is related to the chromosomal sex of the individual. This mode of inheritance is in contrast to the inheritance of traits on autosome chromosomes, where both sexes have the same probability of expressing the trait....
 hypotheses for SIDS and the male excess in infant mortality have shown that the 50% male excess could be caused by a dominant X-linked allele that occurs with a frequency of ? that is protective of transient cerebral anoxia. An unprotected XY male would occur with a frequency of ? and an unprotected XX female would occur with a frequency of . The ratio of ? to is 1.5 to 1 which matches the observed male 50% excess rate of SIDS.

Although many authors have found autosomal and mitochondrial genetic risk factors for SIDS they cannot explain the male excess because such gene loci have the same frequencies for males and females. Supporting evidence is found by examination of other causes of infant respiratory death, such as inhalation of food and other foreign objects. Although food is prepared identically for male and female infants, there is a 50% male excess of death from such causes indicating that males are more susceptible to the cerebral anoxia created by such incidents in exactly the same proportion as found in SIDS. See the data found at http://wonder.cdc.gov for 9ICD 911 and 912 death rates by sex.

The study which indicated that there was a relationship between fewer serotonin binding sites and SIDS noted that the boys "had significantly fewer serotonin binding sites than girls".

Child abuse

Several instances of infanticide
Infanticide

Infanticide is the practice of someone intentionally causing the death of an infant. Often it is the mother who commits the act, but criminology recognizes various forms of non-maternal child murder....
 have been uncovered where the diagnosis was originally SIDS. This has led some researchers to estimate that 5% to 20% of SIDS deaths are infanticides. In 1997 The New York Times
The New York Times

The New York Times is an American daily newspaper published in New York City. The largest metropolitan newspaper in the United States, "The Gray Lady"?named for its staid appearance and style?is regarded as a national newspaper of record....
, covering a book called
The Death of Innocents: A True Story of Murder, Medicine and High-Stakes Science, wrote:
The misdiagnosis of infanticide as SIDS "happens all over," Ms. Talan, a medical reporter at Newsday, said. "A lot of doctors and police don't know how to handle it. They don't take it as seriously as they should." As a result of the book's revelations, people are starting to scrutinize possible cases of this "perfect crime," which involves no physical evidence and no witnesses.


British
United Kingdom

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom , the UK or Britain,is a sovereign state located off the northwestern coast of continental Europe....
 former pediatrician
Pediatrics

Differences between adult and pediatric medicinePediatrics differs from adult medicine in many respects. The obvious body size differences are paralleled by maturational changes....
 Roy Meadow
Roy Meadow

Professor Sir Samuel Roy Meadow is a British paediatrician who rose to initial fame for his 1977 academic paper on the now controversial Munchausen syndrome by proxy and his crusade against parents who wilfully harm or kill their children....
 believes that many cases diagnosed as SIDS are really the result of child abuse
Child abuse

Child abuse is the physical abuse, psychological abuse or child sexual abuse maltreatment of children. The Centers for Disease Control and Prevention defines child maltreatment as any act or series of acts or commission or omission by a parent or other caregiver that results in harm, potential for harm, or threat of harm to a child....
 on the part of a parent displaying Munchausen Syndrome by Proxy (a condition which he was first to describe, in 1977). During the 1990s and early 2000s, a number of mothers of multiple apparent SIDS victims were convicted of murder
Murder in English law

In English law, murder is considered the most serious form of homicide, in which one person kills another either intention in English law to cause death or intending to cause serious injury ....
, to varying degrees on the basis of Meadow's opinion. In 2003 a number of high-profile acquittal
Acquittal

In criminal law, an acquittal is a verdict of not guilty, or some similar end of the proceeding that terminates it with prejudice without a verdict of Guilt y being entered against the accused....
s brought Meadow's theories into disrepute. Several hundred murder convictions were reviewed, leading to several high-profile cases being re-opened and convictions overturned.

The Royal Statistical Society
Royal Statistical Society

The Royal Statistical Society is a learned society for statistics and a professional body for statisticians in the United Kingdom. It was founded in 1834 as the Statistical Society of London....
 issued a media release refuting the expert testimony in one UK case in which the conviction was subsequently overturned.

Nitrogen dioxide


A 2005 study by researchers at the University of California, San Diego
University of California, San Diego

The University of California, San Diego is a public research university in San Diego, California, California. The school's campus contains 694 buildings and is located in the La Jolla, San Diego, California community....
 found that "SIDS may be related to high levels of acute outdoor NO2 exposure during the last day of life." While nitrogen dioxide
Nitrogen dioxide

Nitrogen dioxide is the chemical compound with the chemical formula NitrogenOxygen2. One of several nitrogen oxides, NO2 is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year....
 (NO2) exposure may be one of many possible risk factors, it is not considered causal, and the report cautioned that further studies were needed to replicate the result.

Vaccination


According to the CDC's page on SIDS and vaccines:

Inner ear damage

Records of hearing tests administered to certain infants show that those who later died of SIDS had a unique pattern of partial hearing loss, according to the journal Early Human Development. One suggestion for the cause of SIDS is that the deaths are caused by disturbances in respiratory control (from other than suffocation). The vestibular apparatus of the inner ear has been shown to play an important role in respiratory control during sleep. It is speculated that this inner ear damage could be linked to SIDS. It is speculated that the damage occurs during delivery, particularly when prolonged contractions create greater blood pressure in the placenta
Placenta

The placenta or afterbirth is a highly vascularized ephemeral organ present in Placentalia vertebrates that connects the developing fetal tissues to the uterine wall....
. The right ear is directly in the "line of fire" for blood entering the fetus
Fetus

A fetus is a developing mammal or other viviparous vertebrate, after the embryonic stage and before childbirth. The plural is fetuses, or sometimes feti....
 from the placenta, and thus could be most susceptible to damage. If the findings are relevant, it may be possible to take corrective measures. Researchers are beginning animal studies to explore the connection.

Side effects of SIDS risk reduction recommendations

Dr. Rafael Pelayo from Stanford University and a number of other pediatric sleep researchers in the U.S. have stated that they believe that the American Academy of Pediatrics' recommendations regarding cosleeping and pacifier use may have unintended consequences. They have stated that the SIDS prevention strategy of the American Academy of Pediatrics which keeps infants at a low arousal threshold and reduces the time in quiet sleep may be unhealthy for children. They state that slow wave sleep is the most restorative form of sleep and limiting this sleep in the first 12 months of life may have unintended consequences to both the sleep and the infant.

According to a 1998 study by British researchers that compared back sleeping infants to stomach sleeping infants there were developmental differences at 6 months of age between the two groups. At 6 months of age the stomach sleeping infants had higher gross motor scores, social skills scores, and total development skills scores than the back sleeping infants. The differences were apparent at the 5% statistical significant level. But, at 18 months the differences were no longer apparent. The researchers deemed the lower development scores of back sleeping infants at 6 months of age to be transient and stated that they do not believe the back sleeping recommendations should be changed. Other scientists have stated that the conclusion that the negative effects of back sleep at 18 months of age is transient is based upon very little evidence and that no long-term randomized trials have been completed.

Other side effects of the back sleeping position include increased rates of shoulder retraction, positional plagiocephaly
Positional plagiocephaly

Positional plagiocephaly, also known as deformational plagiocephaly or flathead syndrome, is a condition most commonly found in infants and is characterized by a flat spot on the back or one side of the head caused by remaining in one position for too long....
, and positional torticollis
Torticollis

Torticollis, or wry neck, is a condition in which the head is tilted toward one side, and the chin is elevated and turned toward the opposite side....
. Some scientists dispute that plagiocephaly is a negative side effect. Dr. Peter Fleming, who is co-author of the study that deemed delays at 6 months of age to be transient, has stated that he does not think plagiocephaly is a negative side effect of back sleep. In an interview with the Guardian Dr. Fleming stated "I do not think it is a medical problem—it is more of a cosmetic one. Mothers may feel it is a syndrome and a problem when it really is nonsense." A research study on children with plagiocephaly found that 26% had mild to severe psychomotor delay. This study also showed that 10% of infants with plagiocephaly had mild to severe mental development delay.

Because of the delays caused by back sleep some medical professionals have suggested that the "normal" ages at which children had previously attained developmental milestones should be pushed back. This would enable medical professionals to consider "normal" children who previously were considered developmentally delayed.

Additional studies have found the following negative conditions that the back sleep position has been reported to be associated with are: Increase in Sleep Apnea, Decrease in Sleep Duration, Strabismus, Social Skills Delays, deformational plagiocephaly, and Temporomandibular Jaw Difficulties. In addition, the following are symptoms that are associated with sleep apnea: growth abnormalities, failure to thrive syndrome in infants, neurocognitive abnormalities, daytime sleepiness, emotional problems, decrease in memory, decrease in learning, and a delay in nonverbal skills. The conditions associated with deformational plagiocephaly include visual impairments, cerebral dysfunction, delays in psychomotor development and decreases in mental functioning. The conditions associated with Gross Motor Milestone Delays include speech and language disorders. In addition, it has been hypothesized that delays in motor skills can have a negative impact on the development of social skills. In addition, other studies have reported that the prone position prevents subluxation of the hips, increases psychomotor development, prevents scoliosis, lessens the risk of gastroesophageal reflux, decreases infant screaming periods, causes less fatigue in infants, and increases the relief of infant colic. In addition, prior to the “Back to Sleep” campaign many babies self-treated their own torticollis by turning their heads from one side to the other while sleeping in the prone position. Supine sleeping infants cannot self-treat their own torticollis.

Further reading


External links


Organizations

  • , aims to prevent Sudden Infant Death and promote baby health
  • (support group)
  • (support group)
  • (support group)
  • (promotes education and prevention, funds research and support group)


Related websites

  • at Center for Disease Control
  • Manual for prevention of SIDS and support of affected families.


Media articles

  • , The Times
    The Times

    The Times is a daily national newspaper published in the United Kingdom since 1785 when it was known as The Daily Universal Register.The Times and its sister paper The Sunday Times are published by Times Newspapers Limited, a subsidiary of News International....
  • at BBC
  • Helen Carter, , The Guardian
    The Guardian

    Sorry, no overview for this topic
    , July 8, 2003
  • Wendy Hansen, , Los Angeles Times
    Los Angeles Times

    The Los Angeles Times is a daily newspaper published in Los Angeles, California and distributed throughout the Western United States. It is the second-largest metropolitan newspaper in the United States and the fourth-most widely distributed newspaper in the United States....
    , July 5, 2008


Other articles

  • at the National Institutes of Health
    National Institutes of Health

    The National Institutes of Health is an agency of the United States Department of Health and Human Services and is the primary agency of the United States government responsible for biomedical and health-related research....
  • , AAP
    American Academy of Pediatrics

    The American Academy of Pediatrics was founded in 1930 and now has 60,000 primary care pediatricians, pediatric medical subspecialists and pediatric surgical specialists as members....
  • Phil Stevens, , The O&P Edge