Air pollution might have caused your peanut allergy

Research led by Murdoch Children’s Research Institute (MCRI) and the University of Melbourne has found a link between exposure to air pollution in early life and peanut allergy.

The study was based on a cohort of 5,276 children from Melbourne who were recruited at age one and had follow-ups at four, six and 10 years. Levels of PM2.5 and NO2 around the children’s homes at the time of each follow-up were estimated.

The team found that exposure to higher levels of air pollution in infancy was associated with a greater chance of developing a peanut allergy, and that allergy persisting across the first ten years.

A link between air pollution and egg allergy was also investigated, as was any link with the development of eczema (which also develops in infancy) but no notable association was found.

The fact that the link with peanut allergies was identified in Melbourne is a cause for some concern, given that the city has relatively clean air.

Food allergies are a growing issue in Australia, with one in 10 children affected during the first 12 months of life.

MCRI Associate Professor Rachel Peters 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.

‘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 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.

‘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.’

University of Melbourne’s Dr Diego Lopez suggested that the combination of both peanut allergens and air pollutants in the environment 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.

‘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.’