Air pollution is associated with persistent peanut allergy in the first 10 years

The role of air pollution in eczema and food allergy development remains understudied.

We aimed to assess whether exposure to air pollution is associated with eczema and food allergies in the first 10 years of life.

HealthNuts recruited a population-based sample of 1-year-old infants who were followed up at ages 4, 6, and 10 years. Annual average fine particulate matter (particulate matter with diameter of 2.5 μm or less, or PM_2.5) and nitrogen dioxide (NO₂) exposures were assigned to geocoded residential addresses. Eczema was defined by parent report. Oral food challenges to peanut, egg, and sesame were used to measure food allergy. Multilevel logistic regression models were fitted, and estimates were reported as adjusted odds ratios.

Those exposed to high concentration of NO₂ (<10 ppb) at age 1 year had higher peanut allergy prevalence at ages 1 (adjusted odds ratio [95% confidence interval], 2.21 [1.40-3.48]) and 4 (2.29 [1.28-4.11]) years. High exposure to NO₂ at 6 years old were associated with higher peanut allergy prevalence at age 6 (1.34 [1.00-1.82] per 2.7 ppb NO₂ increase) years. Similarly, increased PM_2.5 at age 1 year was associated with peanut allergy at ages 4, 6, and 10 years (respectively, 1.27 [1.01-1.60], 1.27 [1.01-1.56], and 1.46 [1.05-2.04] per 1.2 μg/m PM_2.5 increase) years. We found that increased concentrations of NO₂ or PM_2.5 at age 1 year were associated with persistent peanut allergy at later ages. Little evidence of associations was observed with eczema or with egg allergy.

Early-life exposure to PM_2.5 and NO₂ was associated with peanut allergy prevalence and persistence. Policies aiming at reducing air pollution could potentially reduce presence and persistence of peanut allergy.