15 Jan 2019

Understanding the allergy epidemic

From Summer Times 2020/2021, 10:20 am on 15 January 2019

Allergies, the bane of so many Kiwis’ lives, have been on the rise in recent decades.

Professor Franca Ronchese's, a Malaghan Institute researcher, is looking at why so many more children have allergies today compared with previous generations and what might be the cause of this increase.

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Photo: Supplied

Ronchese says allergies among children have risen so dramatically that it cannot be put down to genetic reasons alone.

“It’s either exposure, which is unlikely be to the case because obviously allergies to pollen should have been as common as they were. The trees around us haven’t changed, the plants are the same, the indoor environment is probably not that different. It must be something to do with the conditions in which we live,” Ronchese says.

“If one goes and compares the rate of allergies in different countries around the world, they seem to be much more common in Western countries like for example New Zealand, Australia, the UK, the United States and less common in countries where the standard of living is not as high.”

She says this could be down to levels of cleanliness and children having less exposure to bacteria.

“In places like Asia where the standard of living is improving, they are also increasing in the rate of allergies. It seems to be a link to the fact that we have very defined diets, that we’re not exposed to the same environmental pathogens.

“A hundred and fifty years ago, child mortality was still fairly high, now it’s very rare. Infections and diseases that children are affected by will be cured with antibiotics for example.”

Ronchese says the number of changes happening to societies has been so great over the last century, that there’s probably not just one cause, but a combination of causes.

“The fact that the diet is more restricted means that the bacteria we have in our intestinal tract are also less variable. Our diet is more rich, people tend to be heavier and healthier – and all this combination somehow results in increasing allergies. And why, exactly, is difficult to pinpoint.”

However, some things pop up regularly and Ronchese believes they must be credible.

She says there could be a case for saying children aren’t exposed to enough bacteria due to modern cleanliness. For instance, some children in rural Europe who live near animal stables are less likely to develop asthma. However, she says the jury is still out on that.

However, children that live in poverty, especially those in damp homes, are more likely to develop asthma.

She says the fact that children live in damp and mouldy homes is “unacceptable”.

“We study some of these allergens in the lab and they are horrible. They are very damaging to cells. People should not be exposed to that.”

Ronchese says the spores to which children are exposed in damp homes act in a similar way to parasites.

Professor Ronchese was born in Italy and moved to New Zealand in 1994 to set up a research programme at the Institute, after being awarded a Malaghan Senior Research Fellowship. Her group is trying to better understand the initiation of allergic, or "T helper 2" immune responses.

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