10 out of 10 - ten of the greatest health-changing research studies, to have taken place in North Thames over ten years of the CRN

The NIHR Clinical Research Network was formed 10 years ago, in April 2014. To reflect on its mission to support clinical research, we are taking this opportunity to look back on the 10 years of its existence, and revisit some of the incredible research to emerge in the region that has had an impact on treatments and on the health and wellbeing of patients across the UK.

Which aspect of health did this research focus on? 

Public Health.

What was the study investigating?

Low emission zones (LEZ) are an increasingly common intervention aimed at improving urban air quality and public health but their impact had not been evaluated. 

This study, EXHALE, investigated the impact of London's LEZ on air quality and children's respiratory health, to test if improvements in air quality would be associated with improved respiratory health.

Why does it matter?

Air pollution is a leading cause of global mortality. WHO estimates that 7 million people die prematurely from exposure to air pollution every year.

Childhood and adolescence are periods of rapid growth during which organ systems are particularly susceptible to injury, which has impacts that carry into adulthood, with morbidity and mortality linked to reduced adult lung function.

What did the study do?

The phased introduction of London's LEZ, beginning in 2008, provided the opportunity for a natural experiment to evaluate the effect of lowering emissions. 

Over 5 years, the EXHALE study assessed 2,366 children, aged 8–9 years, from 28 primary schools in London boroughs.

It assessed the children's respiratory functions, looked at pollutants in urine and collected information on any respiratory and allergic symptoms from the children’s parents. The levels and pattern of these results was compared to readings of air quality over the study period.

What did we learn?

The study found that within London's LEZ, a smaller lung volume in children was associated with higher annual air pollutant exposure. This is important because children entering adulthood with reduced lung capacity are at risk of asthma, COPD, and earlier death. 50% of COPD is related to reduced lung volume in early adulthood. 

Results were published in The Lancet. 

How has it benefited patient healthcare and treatments? 

The findings had important implications for the health of children living in central London and other high pollution urban environments, as it provided evidence of the link between lung volume and air pollution and suggested that interventions delivering larger reductions in emissions might yield improvements in children's health.

The work has helped inform design of the stricter, ultra low emission zones (ULEZ), and enabled CHILL, a follow up study which aims to determine whether these can improve children’s lung growth and respiratory symptoms, activity levels and brain function.

What next?

The CHILL study is ongoing and since starting, has expanded to explore how air pollution in childhood leaves markers on genes that reflect pollution levels over time and how air pollution can impact cognition and mental health. 

Over the past year, the CHILL study has been featured in the news all over the world including the UK, Ireland, USA, New Zealand, France, China and Malta.