Food allergy (FA) is perceived as a common problem, especially during childhood. Accurate assessment of incidence and prevalence of FA has been difficult to establish, however, due to lack of universally accepted diagnostic criteria. Although many foods are reported to cause IgE-mediated FA, most studies focus on 4 common food groups: cow’s milk, hen’s egg, peanut/tree nuts, and fish/shellfish. There may be variation in the prevalence of FA in regions of the world and a likely increase in prevalence has been observed in recent decades. This cannot be stated with confidence, however, without the use of consistent methodology and diagnostic criteria.
Food allergy (FA) is perceived to be a common problem, especially during childhood. Accurate assessment of incidence and prevalence of FA has been difficult to establish, however, due to lack of universally accepted diagnostic criteria; hence, reported prevalence varies widely across the globe. Research has shown that perceived FA is 10 times higher than what can be confirmed by appropriate tests; hence, studies that rely on self-reports tend to show higher prevalence. The prevalence also depends on which foods or food additives were included and the type of adverse reaction considered. FA is defined as an immune-mediated adverse reaction to foods, and, if there is evidence of allergic sensitization (presence of immunoglobulin E) to a food, it is called IgE-mediated FA. Although many foods have been reported to cause IgE-mediated FA, most studies have focused on 4 common food groups. These are cow’s milk, hen’s egg, peanut/tree nuts, and fish/shellfish. There may be a true variation in the prevalence of FA in different regions of the world and a likely increase in prevalence has been observed in recent decades. This cannot be stated with confidence, however, without the use of consistent methodology and diagnostic criteria.
Reported food allergy
The natural history of FA is such that it is common in early childhood and becomes less common with age. Data from the United States showed that the annual incidence of doctor-diagnosed FA decreased from an average of 4.7% per year during the first 2 years of life to an average of 1.2% for the fifth and sixth years of age. Thus, age is a major factor in determining FA prevalence. Even allowing for that, however, there remains considerable variation in the prevalence of FA in different populations. This is true for overall FA and also for allergy to individual foods. For example, maternally reported or doctor-diagnosed FA in early childhood was 6% in the United States but only 1.7% in Israel. A study from Germany, assessing doctor-diagnosed FA prospectively from 1 to 6 years of age, reported this to be 4.6% at age 1, 6.6% at age 2, and 3.9% from ages 3 to 6. US data from the National Health Interview Survey in 2007 showed reported FA during childhood to be 3.9%.
No two studies of FA prevalence have used the same methodology. Hence, data from the same geographic region often report widely varying prevalences. In France, Penard-Morand and colleagues reported the prevalence of FA in children ages 9 to 11 to be 2.1%. In the same year, Roehr and colleagues estimated FA prevalence to be 6.7% in children ages 2 to 14. In Germany, overall prevalence of reported FA was 20.8% in 1537 subjects, whereas a telephone survey of 4477 adults in the United States showed self-reported FA to be 9.1%. An overall view of FA prevalence was estimated by a meta-analysis of 51 studies. Self-reported FA varied between 3% and 35%, whereas confirmed FA was on average 1% to 10.8% in 6 studies using oral food challenges. Only part of this variation reflects true variation in prevalence; the remainder likely relates to variation in how questions were formulated and which foods were included.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
