Current Issues and SIDS


Welcome to our News Flash! page. We hope to update this page frequently with the newest research concerning SIDS. This is by no means a complete list of topics currently discussed today. Rather, it attempts to address research topics for which we receive the most questions.


The International Conference on Prevention of Infantile Apnea and
Sudden Infant Death: On the Verge of the Millenium

The VIII ESPID Conference, Crowne Plaza Hotel, Jerusalem, May 30 - June 3, 1999

Representatives from nearly 30 countries gathered in the ancient city of Jerusalem to exchange ideas and information on ways to understand and prevent sudden infant death (SIDS). This international conference offered the latest and most significant developments in clinical practice approaches, basic research, and public education. Information was presented in both oral presentation and poster format settings, and focused on several main themes:

1) To further reduce the risk of SIDS and ALTE (Apparent Life-Threatening Events),
2) To increase awareness in all regions of the world,
3) To establish guidelines for better infant care practices,
4) To improve family care and support for bereaved families, and
5) To identify new research directions and priorities for the next century.

Researchers from the American SIDS Institute participated in this comprehensive scientific meeting, and presented the latest findings from ongoing studies at the Institute. Click on the links below to learn more about what was presented by the American SIDS Institute.

A. Curns, A. Steinschneider, H. Shoemake. The prevalence of central apnea in high-risk SIDS infants.

A. Steinschneider, A. Curns, H. Shoemake. Identifying infants at high risk for prolonged bradycardia.

In addition to issues involving prolonged apnea and bradycardia, research was presented on a wide variety of topics as they relate to SIDS:

· Epidemiology & risk factors · Pathology · GERD (Gastroesophageal reflux disorder)
· ALTE · Sleep position · Home monitoring · Congenital disorders · Cardiac factors
· Autopsy issues · Forensic medicine · Factitious Disorder by Proxy · Infections
· Awareness education · Management of high-risk infants
· Grief counseling & intervention · Religious, legal, and ethical aspects

Abstracts for papers presented at the conference can be found in the May 1999 issue of Pediatric Research, Volume 45, Number 5 (Part 2 of 2).


Vaccinations and SIDS

There have been a number of recent news reports addressing childhood vaccinations and the risk of SIDS. In general, these reports claim that vaccination increases an infant's risk of dying from SIDS.

As required by law, children must receive certain immunizations before they can begin school. Of these required vaccinations, several are administered before the child reaches six months of age, including DTP, polio, and now (in many states) Hepatitis B. This period in an infant’s life, however, is also a time when the majority of SIDS cases occur. Ninety percent of all SIDS deaths take place between birth and six months of age, with a peak in cases occurring between 2 and 4 months. It is no wonder, then, that concern is given to a possible relationship between vaccination and sudden infant death.

Many scientific studies have been conducted, both here in the United States and abroad, to evaluate the possibility that vaccination might increase the risk of SIDS. 1-6 Investigators in several of these studies followed two groups of children, one vaccinated and the other unvaccinated, for the occurrence of SIDS. None of these well-controlled scientific studies demonstrated a difference in the number of SIDS cases in the vaccinated group compared to the unvaccinated group. 2,4,5

Several studies did report a range of adverse effects to vaccination, such as fever, malaise, soreness, and irritation. In addition, a few reported very rare severe reactions such as vaccine-associated illness, anaphylaxis (allergic reaction), and neurologic disorders. 3,7-9

When it comes to childhood vaccinations, however, the benefits of participating in these programs far outweigh the risks. For example, it has been estimated that "if there was no DTP immunization program in the United States, pertussis cases could increase 71-fold and deaths due to pertussis could increase 4-fold." 10 Yet the risk of acute encephalopathy, a rare but severe complication from DTP vaccination, is around 5 per 1,000,000. 10

In summary, although carefully done research studies have identified the risk of adverse effects associated with vaccines, they do not support the implication of recent news reports that immunization increases the risk of SIDS. The most reasonable conclusion to be drawn from current scientific literature is that the risk of SIDS is not influenced by vaccinations.
 

  1. Griffin MR, et al. Risk of sudden infant death after immunization with the diphtheria-tetanus-pertussis vaccine. N Engl J Med 1988 Sep8;319(10):618-23.
  2. Jonville-Bera AP, Autret E, Laugier J. Sudden infant death syndrome and diphtheria-tetanus-pertussis-poliomyelitis vaccination status. Fundam Clin Pharmacol 1995;9(3):263-70.
  3. Braun MM, Ellenberg SS. Descriptive epidemiology of adverse events after immunization: reports to the Vaccine Adverse Event Reporting System (VAERS), 1991-1994. J Pediatr 1997 Oct;131(4):529-35.
  4. Carvajal A, et al. [DTP vaccine and infant sudden death syndrome. Meta-analysis] Med Clin (Barc) 1996 May 4;106(17):649-52.
  5. Mitchell EA, Stewart AW, Clements M. Immunisation and the sudden infant death syndrome. New Zealand Cot Death Study Group. Arch Dis Child 1995 Dec;73(6):498-501.
  6. Hoffman HJ, et al. Diphtheria-tetanus-pertussis immunization and SIDS; results of the NICHD Cooperative Epidemiologic Study of SIDS risk factors. Pediatrics 1987. 79:598-611
  7. Howson CP, Fineberg HV. Adverse events following pertussis and rubella vaccines. Summary of a report of the Institute of Medicine. JAMA 1992 Jan 15;267(3):392-6.
  8. Stratton KR, Howe CJ, Johnston RB Jr. Adverse events associated with childhood vaccines other than pertussis and rubella. Summary of a report from the Institute of Medicine. JAMA 1994 May 25;271(20):1602-1605.
  9. Zimmerman RK, Kimmel SR, Trauth JM. An update on vaccine safety. Am Fam Physician 1996 Jul;54(1):185-93.
  10. National Immunization Program. Six common misconceptions about vaccination and how to respond to them. Centers for Disease Control and Prevention (website) http://www.cdc.gov/nip/publications/6mishome.htm.  

Smoking and SIDS

Cigarette smoking by the mother during pregnancy has been consistently shown in epidemiologic studies as a risk factor for SIDS. Most often these studies have relied on self reporting of cigarette usage by the mother. This self reporting may be subject to bias (i.e. under reporting of cigarette use and does not account for use by others) and relying on more objective measures where possible is preferred.

A study published in the Journal of Pediatrics relied on an objective measure to compare the level of tobacco smoke exposure in SIDS victims to a control group of infants that had died of other causes (1). Relying on the cotinine concentration taken from the pericardial fluid, the researchers found that the SIDS victims were more likely to have high concentrations of cotinine in the fluid than the control infants. Cotinine is produced as the liver cleanses the nicotine from the blood and metabolizes it. Higher concentrations of cotinine in the SIDS infants indicated that there was increased exposure to tobacco smoke in this group than in the control group. These results confirm the work of previous studies that have shown that exposure to tobacco smoke increases an infant's risk for SIDS.

With the success of the Back to Sleep campaign, exposure to tobacco smoke prenatally and after birth will likely become the next important risk factor for SIDS that is amenable to intervention. While smoking will be a more difficult risk factor to alter than infant sleep position, the potential benefits are enormous. Decreasing the prevalence of smokers in the U.S., especially in women of child-bearing age, promises to reduce the number of infants lost to SIDS, reduce the amount of respiratory ailments in infants, and at the same time improve the health of the individuals that quit smoking.

1. Milerad J, Vege A, Opdal S, Rognum T. Objective measurements of nicotine exposure in victims of sudden infant death syndrome and in other unexpected child deaths. Journal of Pediatrics. 1998;133:232-236.  

Long QT Interval and SIDS

In June 11's edition of the New England Journal of Medicine, there is a study published on the relationship between a prolonged QT interval and SIDS. Schwartz et al. found that infants with a prolonged QT interval were at greater risk to die of SIDS than those with normal QT intervals (1). They reported that the odds ratio for SIDS was 41.3 times greater in infants with a prolonged QT when compared to infants in the normal range.

The QT interval and its relationship to SIDS has been subject to investigation by numerous researchers with a body of work spanning three decades. It is important to note that aside from Schwartz's work and others working closely with him in Italy, other studies have not shown a clear association between a prolonged QT interval and SIDS (2,3).

The possibility of finding a risk factor so strongly associated with SIDS is certainly intriguing. Yet as the authors caution, the call for screening for SIDS based on the QT interval should be muted for now. Our activities should now be focusing on conducting similar studies to independently verify the hypothesis as well as assessing the immense cost of wide spread screening for a prolonged QT interval and any perceived benefits of such screening.

1. Schwartz PJ, Stramba-Badiale, M, et al. Prolongation of the QT interval and the sudden infant death syndrome. NEJM. 1998;338:1709-14.

2. Weinstein SL, Steinschneider A. QTc and R-R intervals in victims of the sudden infant death syndrome. Am J Dis Child. 1985;139:987-990.

3. Southall DP, Arrowsmith WA, et al. QT interval measurements before SIDS. Arch Dis Child 1986;61:327-333.

What is a QT interval and how might it relate to SIDS?  

SIDS and Air Travel/High Altitudes

A paper published in the British Medical Journal (BMJ) reported that two infants died and were classified as SIDS victims after transcontinental flights (1). The Institute has been barraged by concerned parents and whether air travel for infants is safe. Aside from anecdotal reports such as the one in the BMJ article, there are no scientific studies suggesting that air travel increases an infant's risk for SIDS.

The Institute is currently researching the literature and will update the news on this topic periodically.

You can find the study mentioned above and an editorial response to it at http://www.bmj.org

1. Parkins KJ, Poets CF, O'Brien LM, Stebbens VA, Southall DP. Effect of exposure to 15% oxygen on breathing patterns and oxygen saturation in infants: interventional study. BMJ. No 7135 Vol 316. Saturday March 21, 1998.

Caffeine and SIDS

A case-control study recently found that infants of mothers that consumed large amounts of caffeine (equivalent to 4 or more cups of coffee) were more likely to die of SIDS. The study is the first to report a positive association between SIDS and caffeine intake. The authors note that these results need confirmation by others.

1. Ford RP, Stewart AW, et al. Heavy caffeine intake in pregnancy and sudden infant death syndrome. New Zealand Cot Death Study Group. Arch Dis Child. 1998;78:9-13.


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