The number of people with food allergy in the UK has more than doubled since 2008, with the largest increase seen in young children.
In a new analysis, researchers from Imperial College London estimate that the number of people living with food allergies in England has increased significantly between 2008 and 2018. The analysis found that up to 4% of preschool-aged children have a food allergy, while rates in adults were around 1%. These rates are likely representative of the UK.
The analysis, published in the journal Lancet Public Health, also found that many people with a previous severe reaction from a food allergy (anaphylaxis) were not prescribed adrenaline autoinjector "pens" which can be lifesaving.
The researchers highlight that newly diagnosed cases of food allergy may be levelling-off in some age groups, but say it's unclear whether this might be due to changes in infant feeding guidelines.[1]
However, most patients with food allergy including those with previous anaphylaxis are only seen in the primary care setting: only around 10% were seen at least once by a hospital specialist during the 10-year study period.
The authors say there is an urgent need to ensure GPs and other primary care staff are adequately trained and supported to care for people at risk of severe food allergy.
Dr Paul Turner, Professor of Paediatric Allergy at the National Heart & Lung Institute at Imperial College London, who led the research, said: "This new analysis paints an important, if mixed, picture of food allergy in the UK.
"The good news is that while the prevalence of food allergy has increased, the numbers of new cases occurring each year look to have plateaued. However, more than one-third of patients at risk of severe reactions do not carry potentially lifesaving rescue adrenaline autoinjectors, like EpiPens.
"We urgently need to address this, and better support GPs and primary care staff who end up looking after the vast majority of food-allergic patients in the UK."
Food allergy occurs when the immune system overreacts to certain foods, such as cows' milk, peanuts, eggs or shellfish. In severe cases it can lead to anaphylaxis, which can cause swelling of the airways, breathing difficulties, and cardiac arrest if not treated urgently.
In the latest study, researchers estimated trends in the clinical incidence and prevalence of food allergy in the UK population. Using anonymised data from GP practices[2] covering 13 million patients, the team searched for instances of food allergy between 2008-2018 and linked the data through to relevant GP and hospital encounters in England.
The analysis found that total estimated prevalence of food allergy in the UK increased from 0.4% to 1.1% from 2008 and 2018. In 2018, the highest prevalence was seen in children under 5 years old (4%), with a lower prevalence in school-aged children (2.4% for children aged 5 to 9-years old and 1.7% for 15 to 19-year-olds), and the lowest prevalence in adults (0.7%).
The estimated number of new cases of probable food allergy in the UK doubled between 2008 and 2018, from 76 cases per 100,000 people in 2008 to 160 cases per 100,000 people in 2018.
More than 97% of clinical visits for food allergy were to the GP clinic, rather than the hospital setting, and around 90% of patients only had visits recorded to primary care during the entire 10-year study period. Prescriptions for adrenaline autoinjectors in those with previous anaphylaxis were estimated to be at 64% for children and young people and just 55% for adults. Prescriptions were also less common for people living in more deprived areas of the country.
According to the researchers, their study is the first to describe how the landscape of food allergy has changed in the UK using a large, population-based health dataset. They suggest that while more doctors may have diagnosed food allergy over the past decade, the incidence of new cases may have slowed, possibly due to changes in infant feeding guidelines which no longer recommend delaying the introduction of foods like peanut into the infant diet.[1] In children at higher risk of food allergy (e.g. with infant eczema), earlier introduction of egg and peanut are now standard recommendations.[3]
Professor Adnan Custovic, from the National Heart & Lung Institute at Imperial College London, said: "One concerning finding from our study is the suggestion that patients in more deprived areas of the country may not be getting access to vital rescue medications they need, and may be more likely to attend hospital emergency departments. This urgently requires further investigation."
Professor Jenny Quint, from the School of Public Health at Imperial College London, said: "Our work shows that using large health datasets can help us to cut through the noise and see changing trends in allergy in the UK, and ultimately whether interventions are having an impact."
Earlier this year, Professors Turner and Custovic launched the Frankland-Kay Centre for Allergic Diseases at Imperial College London. The Centre is dedicated to advancing allergy research and reducing the impact of allergies on people and their families.
Dr Turner added: "Food allergy can have a huge impact on people's lives, and in some tragic cases, can cut lives short. By better understanding the prevalence of food allergy in the UK and working with affected people, their families, scientists and clinicians, we are working together to reduce that impact."
The work was funded by the UK Food Standards Agency and the UK Medical Research Council.
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'Time trends in the epidemiology of food allergy in England: an observational analysis of Clinical Practice Research Datalink data' by Paul J Turner, Alessia Baseggio Conrado, Constantinos Kallis, et al. is published in The Lancet Public Health.
[1] See NHS Choices https://www.nhs.uk/conditions/baby/weaning-and-feeding/food-allergies-in-babies-and-young-children/
[2] The study used data from the Clinical Practice Research Datalink (CPRD), supported by the National Institute for Health and Care Research (NIHR), which collects anonymised patient data from a network of GP practices across the UK. https://www.cprd.com/
[3] See British Society for Allergy and Clinical Immunology: Preventing food allergy in your baby. Available at: https://www.bsaci.org/professional-resources/resources/early-feeding-guidelines/
