The causes of asthma and allergies in children are poorly understood. Rates of illness vary between countries, but we don’t yet understand why this is. Much research has been focussed on biological factors, see the ‘nutshell’ on BiB’s Allergy and Infection study for more on this, and social factors are often overlooked.
We have compared rates of asthma and allergies between countries and found that asthma, but not allergies, is most common among poorer children in rich Western countries. If people migrate to these countries from abroad, their family’s risk of illness will, over time, become similar to the general risk of asthma and allergies in the new country.
We also conclude from our research that the gap between the richest and poorest people in a country, and not the average income is associated with asthma and allergies such as hay fever.
We need to investigate the social factors that may explain the difference in risks of asthma and allergies between people and countries. It may be that in a more unequal society, stress and a lack of supportive relationships increases the risk of children developing asthma or allergies.