Association between pacifier use and breast‐feeding, sudden infant death syndrome, infection and dental malocclusion

Executive summary Objective To critically review all literature related to pacifier use for full‐term healthy infants and young children. The specific review questions addressed are: What is the evidence of adverse and/or positive outcomes of pacifier use in infancy and childhood in relation to each of the following subtopics: • breast‐feeding; • sudden infant death syndrome; • infection; • dental malocclusion. Inclusion criteria Specific criteria were used to determine which studies would be included in the review: (i) the types of participants; (ii) the types of research design; and (iii) the types of outcome measures. To be included a study has to meet all criteria. Types of participants The participants included in the review were healthy term infants and healthy children up to the age of 16 years. Studies that focused on preterm infants, and infants and young children with serious illness or congenital malformations were excluded. However, some total population studies did include these children. Types of research design It became evident early in the review process that very few randomised controlled trials had been conducted. A decision was made to include observational epidemiological designs, specifically prospective cohort studies and, in the case of sudden infant death syndrome research, case–control studies. Purely descriptive and cross‐sectional studies were excluded, as were qualitative studies and all other forms of evidence. A number of criteria have been proposed to establish causation in the scientific and medical literature. These key criteria were applied in the review process and are described as follows: (i) consistency and unbiasedness of findings; (ii) strength of association; (iii) temporal sequence; (iv) dose–response relationship; (v) specificity; (vi) coherence with biological background and previous knowledge; (vii) biological plausibility; and (viii) experimental evidence. Studies that did not meet the requirement of appropriate temporal sequencing of events and studies that did not present an estimate of the strength of association were not included in the final review. Types of outcome measures Our specific interest was pacifier use related to: • breast‐feeding; • sudden infant death syndrome; • infection; • dental malocclusion. Studies that examined pacifier use related to procedural pain relief were excluded. Studies that examined the relationship between pacifier use and gastro‐oesophageal reflux were also excluded as