Urban environments significantly increase risk of developing asthma – new research

Study reveals urban exposome impact on asthma risk, highlighting air pollution, lack of green space, and urban design influence.

Asthma is one of the most prevalent chronic diseases worldwide, affecting around 260 million people

Researchers have long know that environmental factors, such as air pollution and lack of green spaces, are linked to respiratory diseases such as asthma. But the joint impact of these various environmental factors on a person’s risk of developing asthma has, until now, remained unclear.

Our study is the first to reveal the joint impact of multiple environmental factors in urban areas, known as the urban exposome, on the risk of developing asthma. We found that air pollution, lack of green space and areas built primarily from concrete and asphalt are linked with significantly greater risk of developing the condition.

To conduct our study, we analysed data from 349,037 participants from across 14 cohorts in Europe. Participants ranged in age from birth to 70 years old. We also linked three major external environmental factors – air pollution, the built-up environment (such as the amount of green space a person had access to or the amount of artificial light they were exposed to at night) and ambient temperature – to participants’ home addresses at the beginning of the study.

Participants were then grouped based on their exposure levels to the three major environmental factors. This allowed us to examine how exposure was linked to the onset of asthma and also calculate what a person’s risk of developing asthma would be if exposed to these environmental conditions. We also accounted for factors that might have affected the results, such as a person’s age, sex, ethnic background, weight, socioeconomic status and whether they smoked (or were exposed to smoke).

We found that adults living in areas with high levels of air pollution had a 13% higher risk of developing asthma compared to people living in low pollution areas. Children living in high pollution areas had an 18% greater risk of developing asthma. Adults living in areas that lacked green space had a 15% greater risk of developing asthma, while children had a 38% greater risk.

But one of the most significant findings of our study was just how much joint exposure to these environmental factors contributed to new asthma cases in both children and adults. We found that the most hazardous urban environments were those characterised by high levels of air pollution, limited access to green spaces and those that were built primarily from concrete and asphalt.