Children Attending Daycare May Have Lower Risk of Asthma and Allergies

— Association of daycare to lower IgE levels seen only for children attending in first year of life


Early-life daycare attendance may be protective against allergen sensitization, according to a study presented at the recent American Academy of Allergy, Asthma & Immunology (AAAAI) annual meeting. The findings were also published in the .

Jonathan Witonsky, MD, assistant professor in the Pediatric Division of Allergy, Immunology, and Bone Marrow Transplant at the University of California San Francisco, explains his research on the impact of early daycare attendance on respiratory illnesses, asthma, and allergies.

Following is a transcript of his remarks:

We've known for quite some time, probably over two decades, that being enrolled in daycare at a young age is actually protective against asthma and allergies. And one thing that's very unique about a project that I'm fortunate to be a part of, a , it's a prospective longitudinal study where we recruited our first mothers to participate, pregnant mothers, in March of 2020 when we had our first expectant mother recruited into the study. And between March of 2020 through June of 2023, we completed enrollment of 2,100 healthy term infants, and over their first 2 years of life through close surveillance, regularly emailing or texting these parents to assess for any respiratory illnesses. And when they have one, especially one that is affecting their lower respiratory tract, we have them come into one of our collaborator's clinics in Caguas, Puerto Rico, where they get fully evaluated and also have nasal swabs collected to look at the viral determinants of those illnesses and look at transcriptomic changes related, potentially related, to those illnesses.

In addition, at birth, we're collecting blood from both the mother and the infant for genetic studies. At year 2 of life, we are collecting blood again from the children to look at complete blood counts, to look at total IgE [immunoglobulin E] levels, look at sensitivities to various environmental and food allergens. Actually, the research that I conducted was primarily looking at the allergy and total IgE testing based on the samples collected at year 2 of life.

Our findings is that there is a fairly significant increase in odds of having a respiratory illness -- both upper and lower respiratory tract involvement -- for children who attend daycare, and this is adjusting for many factors. For example, having other kids in the home where the child is living, the child's age, the child's sex, the child's race, factors about the mother such as her age at time of giving birth, the mother's educational level.

We also found that total IgE levels are lower for children who attend daycare compared to children who do not. But interestingly, we're only seeing that finding if the child attended daycare in their first year of life. If they attended later, for example, in the second year of life, we're not seeing the same association. And then, finally, a specific IgE testing to evaluate for food and perennial aeroallergen sensitization, we're seeing a decreased odds of having those sensitizations among children who attended daycare relative to children who do not.

I think one of the first issues that we need to really just explore is the mechanism that underlies this because we're always seeking early interventions to lessen allergies and asthma in children, which if anything, are growing in prevalence. Would it be safe to say that daycare in of itself is an early intervention that can have that effect? Perhaps too soon to say, in terms of this PRIMERO cohort. Although with that said, I think it can inform the guidance that we provide parents who are perhaps concerned about sending their children to daycare given the increased rates of respiratory illnesses that they will almost certainly have in that setting, that those respiratory illnesses do not seem to necessarily contribute to this relationship. And, if they do, a very small amount.

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    Greg Laub is the Senior Director of Video and currently leads the video and podcast production teams.