Study finds connection between air pollution and childhood peanut allergies

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 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 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.

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."The rise in allergy prevalence has occurred at a similar time to increased urbanization, leading to the belief that environmental factors may be contributing to high allergy rates.

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.

Associate Professor Peters said policies aimed at tackling air pollution could potentially reduce the development and persistence of peanut allergy.

"The research highlights the importance of early-life interventions aimed at reducing exposure to air pollution, which could potentially prevent peanut allergies and other poor child health outcomes," she said.

"Improving city design to support greater air quality regulation, better promoting public transport and switching to non-combustion fuels may help turn the tide on peanut allergy."

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, 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.

"Her allergies are always going to be in the back of her mind, influencing the decisions that she makes every time she eats at a restaurant, orders takeaway or goes to a birthday party. As a family we are learning to manage this new normal as best we can."

"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.

Researchers from Monash University, The University of Sydney, Sydney Local Health District, The Royal Children's Hospital, University of Queensland, Deakin University and the Environment Protection Authority Victoria also contributed to the findings.

Source:

Murdoch Childrens Research Institute

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