Air pollution linked to having a peanut allergy during childhood

Published

Wednesday, October 23, 2024 - 12:01 PM

Exposure to higher levels of air pollution as a baby is linked to having a peanut allergy throughout childhood, according to a new study. And policies aimed at tackling poor air quality could potentially reduce the prevalence and persistence of peanut allergies, it stated.

The research, led by Murdoch Children’s Research Institute (MCRI) and University of Melbourne, found being exposed to higher levels of air pollution from infancy was associated with increased odds of developing a peanut allergy and having the allergy persist across the first 10 years of life. However, the same association was not seen for egg allergy or eczema.

Published in the Journal of Allergy and Clinical Immunology, the study is the first to explore the link between air pollution and challenge-proven food allergy over the first decade of life.

The research involved 5,276 children in Melbourne from the HealthNuts study, recruited at age one and followed-up at four, six and 10 years. The research team used estimates of the annual average concentration of fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) at each participant’s residential address at the time of each follow up.

MCRI Associate Professor Rachel Peters - who is also a Centre for Food Allergy Research Associate Investigator - said the study found that higher levels of air pollution was a risk factor for the development and persistence of peanut allergies. And this was despite Melbourne having generally good air quality compared to our international counterparts, she said.

“The rise in allergy prevalence has occurred at a similar time to increased urbanisation, leading to the belief that environmental factors may be contributing to high allergy rates,” Associate Professor Peters said.

“Eczema and food allergy most often develop in infancy. Both immune conditions can naturally resolve over time, but for some they can persist throughout adolescence and into adulthood.”

“This is the first study to use an oral food challenge, the gold-standard of food allergy diagnosis, to investigate the relationship between food allergy and air pollution.”

Mae, 8, was diagnosed with peanut, diary and egg allergies at 8 months old after an allergic reaction saw her breakout in hives across her entire body. She has since gone onto have several anaphylaxis reactions.

Her mum, Eleanor Jenkin - who is a member of the National Allergy Centre of Excellence Consumer Advisory Group - said the most severe episode occurred five years ago during a food challenge at The Royal Children’s Hospital to check Mae’s tolerance for adding egg back into her diet.

“She was eating cupcakes as part of the challenge until she started to refuse to eat anymore,” she said. We thought she was just being fussy, but she began vomiting and lost consciousness. It was her first anaphylaxis and while it was scary, she returned to her normal self a few minutes after being given an adrenaline shot.”

Since then, Mae has carried an EpiPen with her at all times.

“We were hopeful she would grow out of the food allergies but now we have come to accept that Mae will be living with serious and ongoing allergies,” Eleanor said.

Living in Melbourne’s west, Eleanor said the new MCRI research showed why it was important to tackle air pollution.

“There is a whole suite of reasons why we should be addressing air pollution and its link with peanut allergy just adds to that,” she said.

“Multiple factors are behind the allergy epidemic and if higher levels of air pollution are impacting the prevalence and persistence then that’s an important discovery for families.

“We want to see the quality of life improve for children living with allergies as well as fewer children having to go through what Mae has experienced. The more we know about how to prevent allergies the better.”

University of Melbourne’s Dr Diego Lopez said the co-exposure of peanut allergens in the environment and air pollutants could be increasing the allergy risk.

“Air pollutants have an irritant and inflammatory effect that may boost the immune systems pro-allergic response, potentially triggering the development of food allergies,” he said.

“However, the underlying mechanisms of how air pollution increases the risk of a peanut allergy, and why eczema and egg allergy aren’t impacted in the same way, need to be explored further.”

Read more on the MCRI website.