In a new study in Pediatrics, researchers followed 184 infants from birth until most were 3 years old. The researchers were studying allergy-prone babies, and 80 percent of the group had at least one parent with allergies.
In the first six months of the babies' life, 74 percent of them used a pacifier. Almost all the parents of pacifier-sucking babies said they used tap water to clean the pacifier. Half of the parents said they also boiled them, and another half said they popped dirty pacifiers in their own mouth before handing them back to baby.
At an 18-month check-up, the babies whose parents sucked their pacifiers to clean them were 63 percent less likely to have eczema and 88 percent less likely to have asthma compared with those whose parents did not clean their pacifiers that way.
And those babies whose parents were diligently boiling their baby's pacifiers to clean them? They were more likely to develop asthma than the other babies.