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Hesselmar and colleagues explored whether exposure coming from saliva transferred on a pacifier was related to allergy development among 184 full-term infants born to women enrolled in the AllergyFlora study. For the study, researchers mostly approached families with at least one allergic parent, a situation present for 80% of the participants.
When the children were 6-months-old, the parents were interviewed about pacifier use and cleaning practices and other information.
Overall, 74% of the infants used a pacifier in the first 6 months of life.
For those infants, 83% of parents reported using tap water to clean the pacifiers, 54% reported boiling, and 48% reported using their mouths (parents could select more than one option).
By 18 months, 25% of the children had eczema, 5% had asthma, 15% had sensitization to food antigens, and 2% had sensitization to inhaled antigens.
Pacifier use itself was not associated with the risk of any of those outcomes, but parental sucking on the pacifier was related to a lower likelihood eczema and asthma. Sensitization was not related to pacifier cleaning practices.
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They acknowledged that the study was limited by the small sample size and by the difficulty of diagnosing asthma in early childhood, and called for replication in larger studies and in older children.