Children with asthma who spent the early years of their life living in a social disadvantaged environment, have a greatly increased risk of the condition persisting into adulthood, experts believe.
A new report, published in the international respiratory medicine journal Thorax (Creese et al, 2021), examined the early life environments and circumstances of thousands of UK children and their risk of continued asthma as teenagers.
Researchers from Imperial College London and the University of Liverpool used information from almost 7 500 children born in the UK between 2000 and 2002, and looked at a range of data, such as birthweight, quality of housing and local community and parental smoking habits.
They found that being born into disadvantaged circumstances increased the likelihood of developing persistent asthma by 70%, with almost two thirds (59%) of the risk attributable to early life exposures, before the children reached the age of 3 years.
The researchers said their findings highlight how social and economic factors were driving persistent asthma among the most disadvantaged children in the UK.
About 1.1 million – or one in every 11 children in the UK – have been diagnosed with asthma and are currently receiving treatment for the condition, making it one of the most common long-term conditions in children (Asthma UK, 2021). While the condition is largely manageable, persistent asthma is still responsible for preventable hospitalisations and deaths.
The UK has one of the highest prevalence, emergency admission and death rates for childhood asthma in Europe. Previous studies have also identified that outcomes are worse for children and young people living in the most deprived areas (Royal College of Paediatrics and Child Health, 2021).
According to Asthma UK (2021), someone has a potentially life-threatening asthma attack in the UK every 10 seconds and, on average, three people die from an asthma attack in the UK every day. The cost to the NHS of treating and caring for asthma sufferers every year is estimated to top £1 billion.
Sonia Saxena, Professor of Primary Care at Imperial's School of Public Health, and one of the researchers involved in the study, said: ‘We know that children from poorer backgrounds, who live in disadvantaged circumstances, tend to have a much higher risk of developing asthma, but they also have more asthma attacks, hospitalisations and are more likely to die from asthma.
‘Children with asthma who spent the early years of their life living in a social disadvantaged environment, have a greatly increased risk of the condition persisting into adulthood…’
‘What this study shows is that social and economic disadvantage overwhelmingly takes hold early in life, in the first few years, and has a potential lifelong impact on respiratory and general health.’
During the study, the team looked at a cohort of 7 487 children from England, Scotland, Wales and Northern Ireland, born between 2000 and 2002, taking data at multiple time points throughout their lives – at the age of 9 months, and then at 3, 5, 7, 11 and 14 years.
The children were allocated to six groups, dependent on their mother's level of education:
- Higher degree or first-degree qualifications
- Diploma in higher education
- A levels
- GCSEs (grades a–c)
- GCSEs (grades d–g)
- None of these qualifications.
The researchers said that maternal educational status is a strong proxy for social disadvantage, that tends to cluster from an early age. For example, mothers with the lowest educational attainment are more likely to live in low-income households, where housing conditions are poor overcrowded or damp. Their children are more likely to have passive exposure to cigarette smoke or pollution from living in a polluted or high traffic neighbourhood where air quality is poorest.
‘Any moves to improve air quality and the quality of life generally for children with asthma will have a positive direct impact on their health.’
By tracking the group from infancy up until the age of 14, they compared the impact of a range of physical, socio-economic and environmental factors, such as birthweight, whether they were breastfed, the size of their family and if their parents smoked, as well as wider environmental factors such as housing conditions, proximity to main roads and the environment of their local neighbourhood.
Disadvantaged children were more likely to have a younger mother at birth, belong to a minority ethnic group and live in poorer-quality housing and neighbourhoods, for example, crowded, poor-quality rented accommodation, with no access to a garden, in a built-up area, with heavy traffic or poor air quality.
They found that by age 14, the prevalence of persistent asthma in the most disadvantaged children was 20%, compared with 13% for the most advantaged.
According to the researchers, their study highlighted the toll that inequalities in early life have on health in adolescence and argue that public health measures and policies are urgently needed to support families, address early life behaviours, such as parental smoking, and improve housing conditions for families.
Dr Hanna Creese, a Research Associate within Imperial College's School of Public Health, and first author of the study, said: ‘The wider implication of our work is that if we want to prevent disadvantaged children reaching adolescence and adulthood in worse health than their peers, we need to improve conditions during pregnancy and childhood to support the healthy development of children and reduce inequalities across the life course. This means fundamental changes to housing, education and social care.’
Professor Saxena added: ‘Our work highlights the biggest impact on childhood asthma is coming from the types of exposures you get when you don't have any control over the environment in which you are raising your child.
‘If the government is serious about “levelling up” the UK, it needs to start right at the beginning of life, to ensure children start on an equal footing.’
Dr Jacqui Radley, a GP in the Midlands, said her own experience of treating patients suggested, anecdotally, that children living in urban areas where among the worst affected by childhood asthma.
‘A combination of living conditions, family circumstances and air quality have a huge impact on a child's experience of asthma as a health condition, which is why some schools have put in place measures to reduce vehicle emissions in the streets around their school with car-free zones,’ she said. ‘Any moves to improve air quality and the quality of life generally for children with asthma will have a positive direct impact on their health.’
The research was funded by the National Institute for Health Research, through the Harnessing Data for Child Health work programme in the NIHR School for Public Health Research.