麻豆传媒

SEATTLE -- Some moms or dads would think nothing of "cleaning" their baby's pacifier after it has fallen on the floor by popping it into their own mouths, while others would be horrified by the idea. But the grossed out parents just might be missing an opportunity to help protect their baby from developing allergies later in childhood, according to researchers here.

Parental pacifier sucking was associated with lower early-life total IgE production, suggestive of increased protection from allergy and allergic asthma, reported Edward Zoratti, MD, of the Henry Ford Health System in Detroit, and colleagues at the American College of Allergy, Asthma, and Immunology (ACAAI) annual scientific meeting.

The researchers interviewed more than 100 mothers of infants multiple times over a period of 18 months and asked how they cleaned their child's pacifier. Of the 74 surveyed mothers reporting that their babies used pacifiers, just 12% reported parental pacifier sucking.

"We found that parental pacifier sucking was linked to suppressed IgE levels beginning around 10 months, and continued through 18 months," Zoratti stated. "Further research is needed, but we believe the effect may be due to the transfer of health-promoting microbes from the parent's mouth. It is unclear whether the lower IgE production seen among these children continues into later years."

Co-author Elaine Abou-Jaoude, MD, also of Henry Ford, said it is known that exposure to certain microorganisms early in life stimulates development of the immune system, and may protect against allergic diseases later.

The small study is not the first to suggest a link between parental pacifier sucking and protection from allergy and asthma. A 2013 also showed lower IgE antibodies against common allergens in babies when parents engaged in the practice. The children of pacifier-sucking parents in that study also had less eczema at age 18 months.

"Parental pacifier sucking may be an example of a way parents may transfer healthy microorganisms to their young children," she said. "Our study indicates an association between parents who suck on their child's pacifier and children with lower IgE levels, but does not necessarily mean that pacifier sucking causes lower IgE."

ACAAI spokesperson Neeta Ogden, MD, characterized the study findings as "preliminary but intriguing. This certainly provides some support for the 'hygiene hypothesis' -- the idea that young children exposed to a greater diversity of microbes are less likely to develop allergies later in life," she told 麻豆传媒.

"But, of course, the cohort [of pacifier sucking parents] was very small," she pointed out.

Of 128 mothers completing an interview at 6 months, 74 (58%) reported current child pacifier use. Of these 74, 30 (41%) reported pacifier cleaning by sterilization, 53 (72%) reported hand-washing the pacifier, and 9 (12%) reported parental pacifier sucking.

Pacifier sterilization and handwashing were not associated with serum total IgE trajectory. A significant time interaction was detected for pacifier sucking (P=0.079), indicating that the trajectory shape differed between children of pacifier sucking and non-pacifier sucking parents.

The researchers noted that parental pacifier sucking appeared to suppress serum IgE levels beginning around 10 months (P=0.048), and continued to diverge through 18 months (P=0.014).

They concluded that further research is needed to determine if these differences are due to the transfer of parental oral microbes, and if allergic disease risk later in life is sustained.

Ogden said it is too soon to recommend parental pacifier sucking, but she would not discourage parents from doing it, provided the parents are healthy.

"I would not necessarily tell them not to do it if they were doing it already, or if they wanted to try it, unless, of course, they are sick," she said. "I think there might be something there. But there really needs to be more investigation before we can run with it."

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