The prevalence and temporal trends of food allergy among preschool children in Northern Thailand between 2010 and 2019

Prevention of Food Allergy: Harmonizing Perspectives from the East and West

BACKGROUND

The global epidemiology of food allergies and anaphylaxis exhibits complex, heterogeneous patterns. While food allergy prevalence has stabilized in Western countries, anaphylaxis incidence continues to rise. In developing regions, data are limited, but urban centers show increasing food allergy prevalence, contrasting with lower rates in rural areas. These disparities likely stem from differences in environmental factors and urbanization levels across the globe. Furthermore, the dominant food allergens vary significantly by regions. Peanuts and tree nuts are the primary triggers in the USA and Europe, whereas eggs, milk, and shellfish are more common in Asia and Latin America.

SUMMARY

In this upcoming review, we will delve into the recommendations for preventing food allergies across Eastern and Western regions. These regional differences in allergen profiles and dietary patterns underscore the need for tailored food allergy prevention strategies. Current prevention guidelines focus on the timing and route of allergen exposure in early life. In high-prevalence regions, early oral exposure is recommended to promote oral tolerance and reduce allergy risk. Conversely, in lower-prevalence areas, non-delayed introduction of allergenic solids is preferred. Moreover, early skin exposure may increase allergy risk, and the role of early, whole-body use of specialized emollients requires further study. Proactive treatment of atopic dermatitis may reduce the incidence of food allergies in infants. Adapting prevention approaches to local contexts and continuously updating guidelines based on emerging evidence is crucial to comprehensively addressing the global burden of food allergies.

The Relationship Between Dietary Patterns and the Epidemiology of Food Allergy

Food allergies are increasing globally, particularly in Asia; however, the etiologies of allergic diseases remain poorly understood despite comprehensive studies conducted across a variety of populations. Epidemiological research demonstrates that food allergy is more prevalent in Westernized or urbanized societies than in rural or developing ones. As such, comparing the distribution and patterns of food allergies as well as the environmental exposures between regions may provide insight into potential causal and protective factors of food allergy. Diet is an important exposome that has been shown to modulate the immune system both directly and indirectly via pathways involving the microbiota. Changes in dietary patterns, especially the shift to a Westernized diet with reduced dietary fiber and an abundance of processed foods, impact the gut and skin epithelial barrier and contribute to the development of chronic inflammatory diseases, such as food allergy. Although dietary intervention is believed to have tremendous potential as a strategy to promote immunological health, it is essential to recognize that diet is only one of many factors that have changed in urbanized societies. Other factors, such as pollution, microplastics, the use of medications like antibiotics, and exposure to biodiversity and animals, may also play significant roles, and further research is needed to determine which exposures are most critical for the development of food allergies.

Early-Life Risk Factors and Clinical Features of Food Allergy Among Thai Children

Background: Food allergy affects 1%-10% of children under five worldwide, with genetic and early-life factors playing a primary role. Reported factors include a family history of allergic diseases, personal atopic dermatitis, cesarean section, dietary restrictions during pregnancy and lactation, and the timing of introducing solid foods. This study was aimed at identifying various factors associated with food allergy and evaluate each food allergy's clinical features. Methods: We conducted a case-control study with a participant ratio of 1:2 between cases and controls. Data were gathered from both groups of participants, and questionnaires included living area, sex, and natal history (birth details, maternal diet during pregnancy and breastfeeding, feeding history during infancy, family history of atopic diseases, and household smoking). Results: All 72 cases with food allergy and 145 controls were included in the study. Term birth comprised a protective factor for developing food allergy (adjusted odds ratio [aOR] 0.213, p value 0.022). In contrast, personal atopic dermatitis (aOR 20.097, p value 0.001) and a family history of allergic disease constituted risks (aOR 3.183, p value 0.002). Food allergy was unrelated to cesarean section, low birth weight, dietary restrictions during lactation and pregnancy, exclusive breastfeeding, or the early introduction of complementary foods. The three most common food allergens were egg white (40.2%), wheat (34.7%), and cow's milk (30.5%), respectively. Conclusions: In this study, risk factors associated with food allergy comprised a personal history of atopic dermatitis and a family allergic disease, which may be used as predictive factors for developing food allergy among Thai children.

Eczema in early childhood increases the risk of allergic multimorbidity

BACKGROUND

Eczema in early childhood is associated with the development of subsequent allergic diseases, including food allergy (FA), asthma and hay fever. However, eczema has a heterogenous presentation regarding onset age and persistence, which may lead to different allergic outcomes during childhood/adolescence. Recently, sub-phenotypes of eczema have been suggested as predictors of allergic multimorbidity. Thus, we aimed to identify associations of eczema phenotypes with FA, asthma and hay fever during childhood/adolescence. Additionally, we described the trajectories of eczema, asthma and hay fever stratified by FA presence.

METHODS

TRACKER (Trajectories of Allergy in Children in Real Life Databases) is a population-based cohort study of 6852 children/adolescents from the Lifelines cohort. We investigated the associations of seven eczema phenotypes, based on onset age and persistence, with FA, asthma and hay fever using logistic regression, adjusted for appropriate covariates. Disease trajectories were determined by calculating prevalence at different ages.

RESULTS

Participants who suffered from eczema throughout childhood showed higher risks of developing FA, hay fever and asthma. "Very early onset-persistent" eczema showed the strongest associations with FA, asthma and hay fever. The prevalence of eczema, asthma and hay fever at all ages was significantly higher in participants with FA, compared to those without.

CONCLUSION

One of the largest cohort studies on this topic to date shows that (very) early onset and persistent eczema increases the risk of allergic multimorbidity. Identification of infants at risk for developing (very) early onset eczema is of utmost importance to prevent allergic multimorbidity.

Food allergy in a changing dietary landscape: A focus on the Asia Pacific region

Recent studies have provided compelling evidence to suggest that various environmental factors play a significant role in the development of food allergies. As our society experiences rapid economic growth, increased urbanization, and a shift towards a more Westernized diet, the incidence of food allergies is also on the rise and the pattern is gradually evolving. This review will delve into the changes in the epidemiology of food allergies within the Asia-Pacific region and the various dietary practices and factors that are postulated to play a role in the rise in food allergies over the years. Although there have been important advancements in the field of food allergies, there are still numerous uncertainties regarding the intricate relationship between diet and food allergies. Specifically, the role of epigenetic factors in influencing the susceptibility to food allergies, as evidenced by studies that assessed the impact of migration and rural-urban dynamics, is not fully understood. Addressing this knowledge gap presents an opportunity to develop more effective prevention and treatment strategies that could greatly benefit individuals living with food allergies.

Feast for thought: A comprehensive review of food allergy 2021-2023

A review of the latest publications in food allergy over the past couple of years confirmed that food allergy is a major public health concern, affecting about 8% of children and 10% of adults in developed countries. The prevalence of food allergy varies around the world, with the increase being driven mainly by environmental factors, possibly together with genetic susceptibility to environmental changes. A precise diagnosis of food allergy is extremely important. Both new tests (eg, the basophil activation test) and improved optimization of information provided by existing tests (eg, the skin prick test and measurement of specific IgE level) can contribute to improving the accuracy and patients' comfort of food allergy diagnosis. Understanding the underlying immune mechanisms is fundamental to designing allergen-specific treatments that can be safe and effective in the long term. New discoveries of the immune response to food allergens, including T-cell and B-cell responses, have emerged. Novel therapeutic approaches are being trialed at various stages of development as attempts to allow for more active intervention to treat food allergy. Prevention is key to reducing the increase in prevalence. Early introduction of allergenic foods seems to be the most effective intervention, but others are being studied, and will, it is hoped, lead to modification of the epidemiologic trajectory of food allergy over time.

Food allergy knowledge, attitude and management among preschool personnel in Malaysia

BACKGROUND

Children are vulnerable, and they may experience their first serious food allergy reaction at school, where they spend much of their time. The present study aims to determine the level of food allergy knowledge, attitude and management (KAM) among preschool personnel in Klang Valley, Malaysia.

METHODS

A cross-sectional study was conducted with 292 personnel working in Klang Valley preschools. The participants completed an online questionnaire asking about sociodemographic information and food allergy KAM. Mann-Whitney U and chi-squared tests were used to compare the KAM level between public and private preschool personnel and examine the association of KAM of food allergy with various sociodemographic factors, respectively.

RESULTS

Some 86.3% of the participants demonstrated a low level of food allergy knowledge, 64.7% showed a negative food allergy attitude and 57.9% indicated fair food allergy management. The total mean score for food allergy knowledge was higher (p < 0.01) among the private preschool personnel compared to the public group, although there was no significant difference in attitude (p = 0.244) or practice (p = 0.171). Age group (p < 0.01) and monthly income (p < 0.05) were significantly associated with the level of attitude, whereas no sociodemographic factor was associated with knowledge and management of food allergy.

CONCLUSIONS

Most preschool personnel in Klang Valley have a low level of food allergy knowledge, negative attitudes and a fair level of ability to manage food allergy reactions. The findings of the present study may guide future studies to improve the food allergy KAM of preschool personnel and provide a safer environment for children with food allergies.

Prevalence of self-reported food allergy in Tunisia: General trends and probabilistic modeling

Background

Food allergy (FA) has become a major public health concern affecting millions of children and adults worldwide. In Tunisia, published data on FA are scarce.

Methods

This study, was intended to fill the gap and estimate the frequency of allergy to different foods in the Sfax region, Tunisia, within self-reported FA. One hundred twenty-five (125) children (56% males, 1-17 years old), and 306 adults (17% males, 18-70 years old) were interviewed using a bilingual questionnaire.

Results

The number of self-reported food allergens in this sample was 105; allergens were clustered in 8 foods: fruits, seafood, eggs, milk and dairy, cereals, nuts, vegetables, and peanuts. Cutaneous reactions were the most frequent symptoms, in both children and adults. About 40% of children and 30% of adults had a family history of FA. About 81% of adults and 38% of children are allergic to at least 1 non-food allergen. The most prevalent food allergen was the fruit group in both adults and children, followed by seafood. Most food allergies were mutually exclusive and 90% of individuals have a single FA. The relationship between self-declared FA was modeled using a Bayesian network graphical model in order to estimate conditional probabilities of each FA when other FA is present.

Conclusions

Our findings suggest that the prevalence of self-reported FA in Tunisia depends on dietary habits and food availability since the most frequent allergens are from foods that are highly consumed by the Tunisian population.

Birth order, sibship size, and risk of atopic dermatitis, food allergy, and atopy: A systematic review and meta-analysis

BACKGROUND

Atopic dermatitis and food allergy are two frequently concomitant manifestations of the presence of atopy. A substantial number of studies have been published on the association of birth order and sibship size (number of siblings) with atopic dermatitis, food allergy, and atopy. The present work is the first systematic synthesis of the existing literature on this topic.

METHODS

Fifteen databases were searched. Screening, data extraction, and quality assessment were performed by independent pairs. Comparable numerical data were statistically synthesized using random-effects robust variance estimation.

RESULTS

In total, 114 studies were included out of 8819 papers obtained from database searches. Birth order ≥2 versus 1 was associated with lower risk of ever atopic dermatitis (pooled risk ratio [RR] 0.91, 95% CI 0.84-0.98), current food allergy (RR 0.77, 95% CI 0.66-0.90), and positive skin prick test (SPT) to common aeroallergens (RR 0.86, 95% CI 0.77-0.97). Sibship size ≥2 versus 1 was associated with decreased risk of current atopic dermatitis (RR 0.90, 95% CI 0.83-0.98), ever atopic dermatitis (RR 0.92, 95% CI 0.86-0.97), and positive SPT to common aeroallergens (RR 0.88, 95% CI 0.83-0.92). No putative associations were seen regarding atopy assessed through allergen-specific immunoglobulin E with common allergens.

CONCLUSION

The presence of siblings and being second-born or later may decrease the lifetime risk of atopic dermatitis and food allergy, albeit marginally. Similar association was seen with SPT sensitization. However, significant protection was not found for IgE sensitization.

Allergic sensitization to foods in India and other Low-Middle-income countries

Food allergy is an important cause of morbidity, significantly affecting the quality of life of the sufferer. Most food allergy research has been undertaken in high-income countries. Here, we summarize literature regarding food allergy in India and other low-middle-income countries (LMIC). We provide summaries of self-reported adverse food reactions and food sensitization in these regions by reviewing published community-based studies of prevalence, burden, and risk factors. We identified 2 community-based studies of food allergy prevalence in Karnataka, India, which estimate that food allergy affects just 0.14% of children and 1.2% of adults. The overall prevalence of allergic sensitization to 'any' food was 26.5% in adults and 19.1% in children by serum-specific IgE; but only 4.48% in children by skin prick test. We identified a further 28 studies in other LMICs, mainly from China but also Turkey, South Africa, Ghana, Mexico, Brazil, Thailand, Philippines, and Korea. The overall prevalence of allergic sensitization to 'any' food ranged from 0.11% to 16.8% in children using serum-specific IgE and 0.14% to 9.6% in children by skin prick test. The questionnaires and skin prick testing materials used and number of allergens tested varied significantly between studies. Other than Karnataka, there is no information on prevalence of food sensitization and probable food allergy in the community in India. Similar lack of information is noted among the majority of the 136 LMICs. Where community-based studies have been undertaken, there is wide variation in the prevalence and patterns of food sensitization across different LMICs, at least partly due to variations in study methodology. International collaboration is required in order to formally assess food allergy prevalence and burden across representative samples from multiple LMICs.