Charts on children’s lung function rewritten after study of 2,200 school pupils

Researchers are set to rewrite the charts they use to assess children’s lungs and diagnose respiratory conditions, following an extensive study of more than 2,000 primary school pupils in London.

The £1.2 million study, overseen by Great Ormond Street Hospital’s research partner, the UCL Institute of Child Health (ICH), and funded primarily by the Wellcome Trust, has provided the first clear evidence of the extent to which lung capacities differ between healthy children of different ethnicities.

The ‘Size and Lung Function in Children’ or ‘SLIC’ study means doctors at Great Ormond Street Hospital will soon be able to interpret each child’s lung function results against the most appropriate benchmarks for their ethnic background when diagnosing lung conditions and making decisions on the best treatment.

Janet Stocks, Professor of Respiratory Physiology at the ICH, said data from the study would be used to create new ‘gold standard’ lung growth charts. These new charts will show the normal range of lung capacities for children of different ethnic groups based not only on their gender, age and height as in the past, but also accounting for other factors like body physique (size and shape). This will improve diagnosis of lung disease and also allow researchers to determine the effects of factors such as socio-economic background and environmental pollution on lung health.

Prof Stocks said: “It has been known for about 150 years that there are ethnic differences in lung function, but never before has there been a multi-ethnic study of this size among primary school children to establish the true impact of these differences and how we might minimise them by taking more appropriate measurements of body physique.

“The new lung growth charts that we create will enable clinicians to assess children’s lungs more accurately, irrespective of ethnicity, and improve the diagnosis and treatment of conditions like sickle cell disease, asthma and cystic fibrosis.”

Last year the ICH researchers tested the lung capacity of 1,600 pupils aged 5-11 from 14 London primary schools. They are now undertaking follow-up testing which will increase the total number of pupils recruited into the project to 2,200 and the total number of measurements to more than 3,000.

Prof Stocks said: “In the past, interpretation of lung function was generally based on a child’s height and gender which does not take into consideration differences like chest size. This meant that the same lung capacity would be expected for all children of the same height. However if Child A has longer legs and a shorter body for their total height than Child B, then Child A will have a smaller chest and smaller lung capacity, even if they are completely healthy. Unless body shape and size is taken into account, it could lead to misdiagnosis of lung disease. Conversely a child with lung disease who has shorter legs and a longer body for their age may appear to have normal lung function and not receive appropriate treatment.”

The researchers visited the 14 primary schools in a 23 x 10ft mobile testing lab and provided science workshops alongside the lung measurements, which proved extremely popular with both teachers and children.

Dr Sooky Lum, Senior Research Fellow at the ICH, who is managing the project, said: “We had huge buy-in from head teachers because they liked the idea of helping Great Ormond Street and the Institute of Child Health.”

Commenting on the lung testing that took place at St Joachim’s Catholic Primary School in Newham, headteacher James Allen said:

“This was a good opportunity for the children to make a positive contribution to society in a way other than the usual fundraising. It was also an opportunity for them to see science in use for a real-life purpose, and to meet people who work in science.

“The science workshops that the researchers did with the all the children in the classrooms were fantastic and the children really enjoyed them. It was quite revealing for the children to see how much depth and detail goes into a study.”

The SLIC study involved testing children who were categorised into four main ethnic groups – black, white, South-Asian (Indian subcontinent) and other/mixed ethnicities.

It also took other factors into account, such as the extent to which air quality in large cities such as London may affect children’s lung function.

The new gold-standard lung charts will need to be verified in other parts of the world and extended to older age groups before they can be adopted internationally, but are expected to be in regular use at Great Ormond Street Hospital’s respiratory unit within two to three years.