medwireNews: Food allergy in infancy is associated with impaired lung function and asthma in later childhood, even if it is transient, indicate longitudinal study results.
“In an era of precision medicine and risk communication, these findings will assist clinicians to tailor patient care and direct greater vigilance to monitoring respiratory health of children with food allergies because they have an increased risk of developing adverse respiratory outcomes,” suggest Rachel Peters, from Murdoch Children’s Research Institute in Victoria, Australia, and colleagues.
The team analyzed data for 3233 children from the Australian HealthNuts study. At age 1 year, the children underwent skin prick testing for four food allergens (peanut, egg, sesame and either shrimp or cow’s milk) and an oral food challenge (peanut, egg, sesame),
At age 6 years, they underwent skin prick testing for 10 food allergens (milk, peanut, egg, wheat, sesame, soy, shrimp, cashew, almond, and hazelnut) and eight aeroallergens (Alternaria, Cladasporum, house dust mite, cat hair, dog hair, Bermuda grass, rye grass, and birch mix) plus oral food challenges and lung function tests using spirometry.
Food allergy was defined as developing hives, angioedema, vomiting, or anaphylaxis within 2 hours of oral food challenges and evidence of sensitization on skin pick tests. Food sensitivity was defined as a positive skin prick test result, ie, the development of a wheal greater than 2 mm, or the production of at least 0.35 kilounits of IgE antibodies per liter.
Compared with the 81.8% of infants with no sensitivities at age 1 year, the 13.4% with any food allergy had significantly reduced forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) at 6 years of age, with z-scores of –0.19 and –0.17, respectively.
However, there was no significant association with lung function at 6 years among the 4.8% of participants with any type of food sensitivity aged 1 year.
When the researchers looked at specific food types, they found that children with a peanut sensitivity or allergy at age 1 year had significantly reduced FEV1 (z-scores –0.23 and –0.30, respectively) by 6 years of age, compared with children not sensitive or allergic to peanuts aged 1 year, but only those with an allergy had significantly reduced FVC scores (–0.20). For egg, only children with an allergy at age 1 year had significantly reduced FEV1 and FVC at 6 years old (–0.16 and –0.14, respectively).
Even among those whose egg allergy was transient – present at 1 year and resolved by 6 years – FEV1 and FVC wer significantly reduced at 6 years old, compared with children who never had an egg allergy (–0.18 and –0.15, respectively). For peanut allergy, transient, persistent (present at 1 and 6 years of age), and late-onset (at 6 years old only) allergies were all associated with significant reductions in both respiratory function markers at 6 years of age.
A total of 430 children in the study were diagnosed with asthma by 6 years of age. Those with food sensitivity or allergy at 1 year were a significant 1.97 and 3.69 times more likely than their counterparts with no sensitivity or allergy to have developed asthma, respectively.
“Monitoring children with food allergy for the development of asthma and ensuring that appropriate management strategies are in place remains important because poorly controlled asthma is a risk factor for severe food-induced allergic reactions and anaphylaxis,” write Peters et al in The Lancet Child and Adolescent Health.
The researchers warn that the finding of restrictive as opposed to obstructive lung function deterioration in this pediatric cohort is “concerning” due to recent evidence showing such lung function trajectories are possibly associated with “multiple adult cardiometabolic outcomes.”
Despite this, they support international guidelines that recommend against screening infants for food sensitivities in the absence of “a strong suspicion of a clinically relevant food allergy,” saying that it “can lead to unnecessary allergen avoidance.”
Indeed, Matthew Greenhawt (University of Colorado School of Medicine, Aurora, USA) and Wanda Phipatanakul (Harvard Medical School, Boston, Massachusetts, USA) caution in a related comment that indiscriminate screening can lead to “misdiagnosis and unnecessary avoidance, potential nutritional deficits and diminished quality of life.”
They further remark that the “how and why” for Peters and colleagues’ findings are “yet to be established,” noting that the research team’s hypothesis that the inflammatory effects of an allergic reaction to food could indicate a possible common pathway with poor lung function.
“To ensure this finding is not spurious or associated with a spirometry technique that is still evolving in young children, children within this same cohort need to be observed to an older age, and the analysis ought to be replicated within other similar cohorts with challenge-proven food allergy data,” the commentators conclude.
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