Logotipo de la Evidencias en Pediatría[D]   Number2

What should pediatricians recommend regarding the use of pacifier in infants? Reflections and comments on its role in the reduction of sudden infant death syndrome (SIDS)

Authors: Albert Balaguer Santamaría. Unidad Neonatología y Servicio de Pediatría. Hospital Universitari Sant Joan. Universitat Rovira i Virgili. Reus-Tarragona. España. albert.balaguer@urv.net
Javier González de Dios. Departamento de Pediatría. Hospital Universitario San Juan. Universidad Miguel Hernández. Alicante. España. gonzalez_jav@gva.es
José Luis Diaz-Rossello. Centro Latino Americano de Perinatología y Desarrollo Humano y Unidad de Salud de la Mujer y Reproductiva (CLAP/SMR). Organización Panamericana de Salud. Organización Mundial de la Salud. (Uruguay). diazjose@clap.ops-oms.org

English key words:pacifiers; sudden infant death: prevention and control; case-control studies; meta-analysis
Spanish key words: chupete; síndrome de muerte súbita del lactante: control y prevención; estudios de casos y controles; metaanálisis

Received: May 14, 2006
Accepted: May 15, 2006

Sudden infant death syndrome (SIDS) is the sudden death of an infant under 1 year of age, which remains unexplained after a thorough case investigation, including a complete autopsy, examination of the death scene, and review of the clinical history1,2. It remains one of the leading causes of infant mortality. It is rare during the neonatal period, increases to a peak between 2 and 3 months of age, and then decreases until the first year of life.

A number of risk factors that increase the risk for SIDS have been identified across studies comparing the frequency among SMSL cases and matched controls. The first risk independent factors collected in population based case-control studies are: prone sleep position, sleeping on a soft surface, overheating, maternal smoking during pregnancy, young maternal age, preterm birth and/or low birth weight, and male gender. In 1992, in response to epidemiological reports from Europe and Australia, the American Academy of Pediatrics (AAP) recommended that infants be laid down (first it advised that the nonprone position, and then the supine position)3, what led to the “Back to Sleep” campaign, that has been implemented around the world, and that has been associated with the decrease in the incidence of SIDS. Since then new variables have been associated with SIDS, and AAP (Task Force on Sudden Infant Death Syndrome)4,5 has updated the new recommendations that have been published in November 2005. The AAP5 includes offering a pacifier at nap time and bedtime in infants up to 1 year of age.

The protective effect of pacifiers against SIDS has been known for some time. In 1979, Cozzi et al6 postulated that pacifiers might protect against sudden infant death syndrome (SIDS). Support for this hypothesis was first reported in New Zealand in 19937. Since then there have been other studies that have supported this observation. There have been 7 case-control studies published in the meta-analysis in Pediatrics of November 20058 (5 studies come from European countries, 1 from United States, and 1 from New Zealand) and a prospective study in Scandinavia whose unpublished data are in the report published in Pediatrics in May, 20069. Some of the studies point to a direct beneficial effect of pacifiers evidenced by the findings that usual pacifier use was not protective whereas last sleep use was. That is if the infants habitually used a pacifier but did not do so on the night of last sleep, the protective effect would disappear. Pacifier would act as a security belt that protects during the trip, although in this case could protect in some way, due to the previous use10. Support for this hypothesis was reported in previous and subsequent studies to the “Back to Sleep” campaign.

In the recent meta-analysis by Hauck et al8, usual pacifier use was shown to be associated with a non significant decreased risk of SIDS, the Odd Ratio (OR) calculated for univariate OR were 0.90 [95% CI: 0.79-1.03]). However, based on studies of multivariate OR, usual pacifier use was associated with a significant reduced risk of SIDS (OR: 0.71 [95% CI: 0.59-0.85]). For the pacifier use during last sleep, the OR calculated for univariate OR, were 0.47 (95% CI: 0.40-0.55) and for multivariate OR were 0.39 (95% CI: 0.31-0.50). From the results of this meta-analysis 1 SIDS death could be prevented for every 2733 (95% CI: 2416-3334) infants who use a pacifier when placed for sleep (number needed to treat), based on the number of SIDS rate in United States, and the last-sleep multivariate OR resulting from this analysis. The review by Mitchell et al9 reports consistent results (including 2 unpublished studies) All of them showed a reduced risk of SIDS (OR: 0.83 [95% CI: 0.75-0.93]) for routine pacifier use and OR: 0.48 [95% CI: 0.43-0.54]) for pacifier use for the last sleep.

The relation between pacifier and SIDS decrease fulfils the conditions that determine the causality: consistent findings, strong association, dose-response effect, biological plausibility and causal factor preceding the outcome8. After the last studies8,9, new publications have came out that confirm the findings, one in Germany11 and another one in the United States12. The last one is critically appraised in this issue of “Evidencias en Pediatría”13. In this study the adjusted odds ratio was 0.08 (95% CI: 0.03-0.21), which translates to a 92% reduction of risk in infants who used a dummy during the last sleep compared with infants who did not use it. There was a consistent trend towards use of a dummy during sleep being associated with a greater reduction of risk when an infant was in an adverse sleep environment (sleeping prone or on the side, sleeping with a mother who was a current smoker, or sleeping on soft bedding).

According to these results using the pacifier could be included as a level B strength of recommendation (according to the U.S. Preventive Service Task Force) based on the consistence of findings among the available studies (case-control studies which are of weaker design than controlled trials or cohort studies), and the likelihood that the beneficial effects will outweigh any potential negative effects.

How could we translate these evidences into clinical practice? The “Back to Sleep” campaign has been shown to be efficacious and efficient, in decreasing the SIDS in many countries. Why is different, according to what has been stated above, to promote the use of pacifier in infants throughout the first year of life?. The two reasons that might be argued against this recommendation are: the mechanism for this protective effect is unknown and the detrimental effects associated.

We can begin by the less conflicting: the mechanism by which pacifiers might reduce the risk of SIDS (or its absence increase the risk) is unknown, but several mechanisms have been postulated: avoidance of the prone sleeping position14, protection of the oropharyngeal airway6, reduction of gastroesophageal reflux through nonnutrient sucking7 and lowering the arousal threshold15.

But we believe that the most limiting are the potential disadvantages: reduction in breastfeeding, higher risk of infections, dental malocclusion, accidents, etc. The main concerns are related to the reduction of breastfeeding16,17, although the well-designed randomized clinical trials have produced conflicting results18-20, the recommendation against pacifier is included in the leaflets that promote breastfeeding and its diffusion has spread across the world; it also takes part of one of the ten steps to successful breastfeeding. The same concerns came across with the potential association of pacifier use and higher risk of otitis media which could be the result of confounding factors21. Dental malocclusions are usually associated with a long term use, and are unlikely to develop if stopped by 6-12 months of life.

There are two levels in including into clinical practice this knowledge as the protective effect of pacifier against SMSL:
- First, it seems appropriate to stop discouraging the use of pacifier. Evidence is available since several years ago ,that is no new, as one of the authors explained six year ago (10), and now acknowledged by recent reviews5,8,9,22,23.
- Second, pacifier should be recommended throughout the first year of life according to the following procedures:

  1. For breastfeed infants, delay pacifier introduction until 1 month of age to ensure that breastfeeding is firmly established.
  2. In children feed with bottle offer the pacifier in the first days of life, because their mothers have other characteristics that may place their infants at greater risk for SIDS.
  3. The pacifier should not be reinserted once the infant falls asleep.
  4. Pacifiers should not be coated in any sweet solution
  5. Pacifier should be phased out at the end of the first year of life

Our responsibility is to avoid preventable sudden infant deaths, and that implies to protect against all known factors23. If parents choose to use one, evidence-based advices on how to use it need to be given, to help them make these important decisions. We are reopening a new controversial topic, with increasing evidence accumulated that implies that it seems appropriate to stop discouraging the use of pacifier.

Bibliography

  1. Willinger M, James LS, Catz C. Defining the sudden infant death syndrome (SIDS): deliberations of an expert panel convened by the National Institute of Child Health and Human Development. Pediatr Pathol. 1991; 11: 677-84.
  2. Beckwith J. Defining the sudden infant death syndrome. Arch Pediatr Adolesc Med. 2003; 157: 286-90.
  3. Katwinkel J, Brooks J, Yerterg D; American Academy of Pediatrics AAP, Task Force on Infant Positioning and SIDS: Positioning and SIDS. Pediatrics. 1992;89(6 Pt 1):1120-6.
  4. American Academy of Pediatrics, Task Force on Infant Sleep Position and Sudden Infant Death Syndrome. Changing concepts of sudden infant death syndrome: implications for infant sleeping environment and sleep position. Pediatrics. 2000; 105: 650-6.
  5. American Academy of Pediatrics, Task Force on Sudden Infant Death Syndrome. The changing concept of sudden infant death syndrome: diagnostic coding shifts, controversies regarding the sleeping environment, and new variables to consider in reducing risk. Pediatrics. 2005; 116: 1245-55.
  6. Cozzi F, Albani R, Cardi E. A common pathophysiology for sudden cot death and sleep apnea: “the vacuum-glossoptosis síndrome”. Med Hypotheses. 1979; 5: 329-38.
  7. Mitchell EA, Taylor BJ, Ford RP, Stewart AW, Becroft DM, Thompson JM, et al. Dummies and the sudden infant death syndrome. Arch Dis Child. 1993; 68: 501-4.
  8. Hauck FR, Omojokun OO, Siadaty MS. Do pacifiers reduce the risk of sudden infant death syndrome? A meta-analysis. Pediatrics. 2005; 116: e716-23.
  9. Mitchell EA, Blair PS, L'Hoir MP. Should pacifiers be recommended to prevent sudden infant death syndrome?. Pediatrics. 2006; 117: 1755-8.
  10. Díaz-Rossello J, Conde-Agudelo A, Carolina Forteza A. Pacifiers: protection against sudden infant death syndrome. Lancet. 2000; 355: 1829.
  11. Vennemann MM, Findeisen M, Butterfass-Bahloul T, Jorch G, Brinkmann B, Kopcke W, et al. Modifiable risk factors for SIDS in Germany: results of GeSID. Acta Paediatr. 2005; 94:655-60.
  12. Li DK, Willinger M, Petitti DB, Odouli R, Liu L, Hoffman HJ. Use of a dummy (pacifier) during sleep and risk of sudden infant death syndrome (SIDS): population based case-control study. BMJ. 2006;332:18-22.
  13. Righard L. Sudden infant death syndrome and pacifiers: a proposed connection could be a bias. Birth. 1998; 25: 128-9.
  14. Franco P, Scaillet S, Wermenbol V, Valente F, Groswasser J, Kahn A. The influence of a pacifier on infants' arousals from sleep. J Pediatr. 2000; 136: 775-9.
  15. Victora CG, Behague DP, Barros FC, Olinto MT, Weiderpass E. Pacifier use and short breastfeeding duration: cause, consequence, or coincidence?. Pediatrics. 1997; 99: 445-53.
  16. Howard CR, Howard FM, Lanphear B, deBlieck EA, Eberly S, Lawrence RA.The effects of early pacifier use on breastfeeding duration. Pediatrics. 1999;103:e33.
  17. Howard CR, Howard FM, Lanphear B, Eberly S, deBlieck EA, Oakes D, et al. Randomized clinical trial of pacifier use and bottle-feeding or cupfeeding and their effect on breastfeeding. Pediatrics. 2003;111:511-8.
  18. Kramer MS, Barr RG, Dagenais S, Yang H, Jones P, Ciofani L, Jane F. Pacifier use, early weaning, and cry/fuss behavior: a randomized controlled trial. JAMA. 2001; 286: 322-6.
  19. Collins CT, Ryan P, Crowther CA, McPhee AJ, Paterson S, Hiller JE. Effect of bottles, cups, and dummies on breast feeding in preterm infants: a randomised controlled trial. BMJ. 2004;329: 193-8.
  20. Niemela M, Pihakari O, Pokka T, Uhari M. Pacifier as a risk factor for acute otitis media: A randomized, controlled trial of parental counseling. Pediatrics. 2000;106:483-8.
  21. Hauck FR. Pacifiers and sudden infant death syndrome: what should we recommend?. Pediatrics. 2006;117:1811-2.
  22. Alm B, Lagercrantz H, Wennergren G. Stop SIDS-sleeping solitary supine, sucking soother, stopping smoking substitutes. Acta Paediatr. 2006; 95: 260-2.

How to cite this article

González de Dios J, Balaguer A, Díaz-Rossello JL. ¿Qué actitud adoptaremos los pediatras respecto al uso del chupete en el lactante? Reflexiones y comentarios en relación con su potencial papel protector en el síndrome de muerte súbita del lactante. Evid Pediatr. 2006; 2:15.