ABSTRACT. Objective. Pacifier use has been reported to be associated with a reduced risk of sudden infant death syndrome (SIDS), but most countries around the world, including the United States, have been reluctant to recommend the use of pacifiers because of concerns about possible adverse effects. This meta-analysis was undertaken to quantify and evaluate the protective effect of pacifiers against SIDS and to make a recommendation on the use of pacifiers to prevent SIDS.Methods. We searched the Medline database (January 1966 to May 2004) to collect data on pacifier use and its association with SIDS, morbidity, or other adverse effects. The search strategy included published articles in English with the Medical Subject Headings terms "sudden infant death syndrome" and "pacifier" and the keywords "dummy" and "soother." Combining searches resulted in 384 abstracts, which were all read and evaluated for inclusion. For the meta-analysis, articles with data on the relationship between pacifier use and SIDS risk were limited to published original case-control studies, because no prospective observational reports were found; 9 articles met these criteria. Two independent reviewers evaluated each study on the basis of the 6 criteria developed by the American Academy of Pediatrics Task Force on Infant Positioning and SIDS; in cases of disagreement, a third reviewer evaluated the study, and a consensus opinion was reached. We developed a script to calculate the summary odds ratio (SOR) by using the reported ORs and respective confidence intervals (CI) to weight the ORs. We then pooled them together to compute the SOR. We performed the Breslow-Day test for homogeneity of ORs, Cochran-Mantel-Haenszel test for the null hypothesis of no effect (OR ‫؍‬ 1), and the MantelHaenszel common OR estimate. The consistency of findings was evaluated and the overall potential benefits of pacifier use were weighed against the potential risks. Our recommendation is based on the taxonomy of the 5-point (A-E) scale adopted by the US Preventive Services Task Force.Results. Seven studies were included in the meta-

We would like to comment on the meta-analysis 1 recently published in Pediatrics that focuses on the relationship between the use of a pacifier and sudden infant death syndrome (SIDS), as well as the American Academy of Pediatrics policy statement 2 that recommends the use of a pacifier as a possible preventive factor of sudden death.As previously highlighted, 3 methodologic reasons should advise against giving any value to comparisons based on "last sleep." Indeed, last sleep is an exclusive feature of a dead infant. An infant who doesn't die cannot experience the "last sleep before dying!" It seems to be quite clumsy to try to surrogate the absence of last sleep in the control group with a poorly convincing "reference sleep" (that is only 1 particular sleep among many and, therefore, should be considered "usual sleep").In contrast, it would be reasonable to make comparisons based on common exposures (eg, gender, bottle or breastfeeding, parent's smoking, usual sleeping position, bed sharing, pacifier use, etc).Taking this approach as our inclusion criterion, we found only 5 studies that compared the use of a pacifier in cases versus controls (search was limited to PubMed and English-language articles).The effect of pacifier use measured in terms of odds ratio (OR) and estimated by using both univariate and multivariate analyses (4 studies; OR was adjusted for different variables across studies) is smaller than that observed for the last sleep, thus suggesting caution when taking last sleep as a valid indicator.Others elements of concern regard the reliability of the estimates obtained in the primary studies, such as the adjustment for several variables in relatively few subjects (the study with the biggest effect had 73 cases of SIDS) and the recruitment of several controls for each case, which tend to amplify the effect. The lack of an assessment of methodologic quality and the use of fixed models to combine results that do not take into account the high level of observed variability among results should suggest the use of these results with extreme caution. 4 In the absence of clear and strong evidence in support of the use of pacifiers (which could have some adverse effects on breastfeeding), we think it would be more appropriate not to provide any recommendations.

Sudden Infant Death Syndrome (SIDS) is characterized by the sudden death of an infant, unexpected by history and unexplained by a postmortem exam. The rate of SIDS has decreased markedly since the launch of the Back to Sleep campaign and other public health initiatives. Despite these efforts, SIDS remains the third leading cause of infant death and the leading cause of postneonatal deaths in the United States. The cause of SIDS is unknown, but autopsies have suggested that asphyxia and central nervous system abnormalities, among other findings, may play a role. Environmental risk factors, such as maternal smoking and infant sleep position, are multifactorial and documented throughout the medical literature. The influence of genetics on SIDS risk is not as well-understood at this time, but recent data have demonstrated associations between specific polymorphisms and SIDS, suggesting that interactions among environmental and genetic factors contribute to SIDS susceptibility. Recent data regarding the protective effects of pacifiers and breastfeeding are discussed. Risk reduction guidelines for physicians, parents, and other caretakers are outlined in this review of the literature, with particular emphasis on the 2005 recommendations from the American Academy of Pediatrics.