North-south differences in US emergency department visits for acute allergic reactions

Early exposure to sunlight and allergic morbidity: The PARIS birth cohort

The relationship between sunlight and allergies in children has received limited attention from researchers. We sought to explore how early exposure to solar radiation is associated with allergic morbidity within the PARIS birth cohort study. Our research dealt with children who attended at least one of two health checkups: at 18 months (n = 2012) and at 8-9 years (n = 1080). Early exposure to solar radiation was assessed using meteorological data (e.g., solar radiation, temperature, and relative humidity). Children with similar meteorological exposure trajectories were grouped by a longitudinal and multidimensional cluster analysis. The association between solar radiation exposure and allergic morbidity (i.e., allergic sensitization at 18 months and 8-9 years; current asthma, rhinitis, and eczema at 8-9 years) was quantified by multivariable logistic regression models adjusted for potential confounders. The effect modification of maternal vitamin D supplementation during pregnancy was tested. Four meteorological exposure trajectories were found. The trajectory with the highest exposure to early solar radiation had a reduced risk of sensitization at 8-9 years compared to the trajectory with the lowest exposure (p = 0.06). The association was statistically significant in the vitamin D supplementation group. Solar radiation during prenatal and postnatal periods was significantly associated with a lower risk of sensitization at 8-9 years (for one interquartile range (IQR) increase, adjusted odds ratio (aOR): 0.47; 95 % confidence interval (CI): 0.25-0.87 and 0.84; 0.7-1.00, respectively). Increased prenatal exposure to solar radiation was significantly associated with a lower risk of asthma at 8-9 years (for one IQR increase, aOR: 0.32; 95 % CI: 0.1-0.96). Early sunlight exposure may reduce the risk of sensitization and asthma in school-aged children, especially in those prenatally exposed to vitamin D. These findings highlight the importance of vitamin D in preventing allergic diseases in children, either through supplementation or sunlight exposure.

A narrative review of vitamin D and food allergy in infants and children

OBJECTIVE

This article summarizes the research progress on the association of vitamin D and food allergy in infants and children.

BACKGROUND

In recent years, food allergy seriously has affected the quality of life of children and adults. Vitamin D is known to be involved in calcium and phosphorus metabolism, and recent research has demonstrated that vitamin D can also affect the immune regulation of food allergy.

METHODS

The present study summarizes the research progress on the association of vitamin D and food allergy in infants and children. We searched the PubMed database to identify studies on the association of vitamin D and food allergy published between January 2003 and August 2021.

CONCLUSIONS

Vitamin D in the body through a number of steps into the final formation of biological effects. The implications of postnatal vitamin D levels for food allergy may be even greater. Vitamin D can prevent the intestinal immune system from being exposed to allergens by maintaining the integrity of the mucosal barrier. Many clinical studies believe that vitamin D supplementation can improve infants' and children's food allergy, however, some show negative results or opposite results. A lot of laboratory studies have confirmed that vitamin D is involved in the immune regulation of food allergy. Evidence indicates there may be a nonlinear relationship between vitamin D and food allergy. Further researches need to be launched.

Food Allergy Prevention: More Than Peanut

Given an apparent increase in food allergies worldwide, the focus on prevention strategies has intensified. Following the Learning Early About Peanut study, there is now a widespread acceptance that peanut should be introduced promptly into the diet of high-risk infants. However, most food allergies are caused by triggers other than peanut and additional prevention strategies are being evaluated. The appreciation of the role of an impaired skin barrier in the process of food sensitization and subsequent allergy has led to a spectrum of dermatologically orientated studies. Other prevention strategies address the role of the microbiome, dietary components, and other modifiable risk factors. With regard to early introduction of foods other than peanut, studies are heterogeneous in design and governmental and professional society response to the early introduction trials has varied, ranging from new guidelines confining advice specifically to peanut, to ones recommending prompt introduction of a broad spectrum of allergenic foods. Much remains to be determined with regard to the acceptability and uptake of the new guidelines and their impact on infant feeding behavior and food allergy outcomes. This review discusses the panoply of prevention approaches, their promise, and limitations.

Guiding Principles for the Recognition, Diagnosis, and Management of Infants with Anaphylaxis: An Expert Panel Consensus

Infant anaphylaxis is an emerging risk, with food allergy the most common cause. Although the presentation of anaphylaxis involves the same systems as in older children and adults, there are real-world challenges to identifying symptoms of an allergic emergency in nonverbal children, as well as implementing optimal treatment. Recognition of anaphylaxis in infants can be challenging because allergic symptoms and certain normal infant behaviors may overlap. Intramuscular epinephrine is the treatment of choice for infants, as it is for older children and adults, and an epinephrine autoinjector approved by the Food and Drug Administration is now available for infants weighing between 7.5 and 15 kg. A panel of experts sought to develop guiding principles for the recognition, diagnosis, and management of anaphylaxis in infants, and provide a framework for the development of new guidelines and future research. Accordingly, anaphylaxis emergency action planning for infants was addressed by the panel. In considering formation of future infant anaphylaxis guidelines, health care providers should be aware of the needs to improve the recognition, diagnosis, and management of infants with anaphylaxis. Future research should identify and validate clinical criteria for the diagnosis of anaphylaxis in infants, as well as risk factors for the most severe reactions.

Long-Term Outcome of Peanut Oral Immunotherapy Facilitated Initially by Omalizumab

BACKGROUND

We successfully used omalizumab to facilitate peanut oral immunotherapy (OIT) in children with reactivity to ≤50mg peanut protein and with high peanut IgE (median, 229 kU/L).

OBJECTIVE

We report on long-term OIT outcomes in these patients, including dosing changes, adverse events, peanut immunoglobulin changes, and quality of life (QoL).

METHODS

Patients were followed for up to 72 months (67 months of maintenance). Outcomes were collected on peanut dose amount, form, and frequency, as well as adverse events, (QoL), and laboratory studies.

RESULTS

Of 13 patients initially enrolled, 7 patients (54%) continued on peanut OIT through month 72; 6 (46%) discontinued therapy because of adverse reactions. Maintenance peanut protein dose varied between 500 and 3500mg. Most patients consumed different peanut-containing products. All patients experienced at least 1 adverse event, and 1 patient developed eosinophilic esophagitis. Peanut-IgE, Arah1-IgE and Arah2-IgE, peanut-SPT, peanut-IgE:IgE ratio, and Arah2-IgE:Arah2-IgG4 ratio decreased on OIT. Peanut-IgG4, Arah1-IgG4, and Arah2-IgG4 initially increased on OIT and then decreased, though not falling to baseline levels. In patients who stopped OIT, there was a trend for reversal of these biomarker changes. Higher peanut-IgE and Arah2-IgE at study month 12 were associated with discontinuation. Patient and parent QoL improved from baseline, even in patients who discontinued OIT.

CONCLUSIONS

Although adjunctive omalizumab allowed for faster and successful desensitization in patients with high peanut-IgE, almost half of patients discontinued OIT within 72 months because of reactions. Patients who stopped therapy had higher month 12 peanut-IgE and Arah2-IgE. It is possible that these patients might benefit from longer omalizumab administration.

The Epidemiology of Anaphylaxis

Anaphylaxis is a dramatic expression of systemic allergy. The lifetime prevalence of anaphylaxis is currently estimated at 0.05-2 % in the USA and ~3 % in Europe. Several population-specific studies have noted a rise in the incidence, particularly in the hospitalizations and ER visits due to anaphylaxis. The variable signs and symptoms that constitute the diagnostic criteria for anaphylaxis, the differences in diagnostic algorithms, and the limitations in the current coding systems have made summarizing epidemiologic data and comparing study results challenging. Nevertheless, across all studies, the most common triggers continue to be medications, food, and venom. Various risk factors for more severe reactions generally include older age, history of asthma, and having more comorbid diseases. Interesting seasonal, geographic, and latitude differences have been observed in anaphylaxis prevalence and incidence rates, suggesting a possible role of vitamin D and sun exposure in modifying anaphylaxis risk. While the incidence and prevalence of anaphylaxis appear to be increasing in certain populations, the overall fatality rate remains relatively low.

Risk factors for recurrent anaphylaxis-related emergency department visits in the United States

BACKGROUND

Anaphylaxis is a potentially life-threatening allergic reaction with a strong risk of recurrence.

OBJECTIVE

To assess risk factors associated with recurrent anaphylaxis-related emergency department (ED) visits within 1 year of an ED visit for anaphylaxis in a large observational cohort study.

METHODS

We used an administrative claims database to identify patients seen from 2008 through 2012 in the ED for anaphylaxis based on an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code algorithm. Patients with at least 2 years of continuous enrollment in a health plan were included. Multivariable logistic regression analysis was used to determine associations with recurrence of anaphylaxis within 1 year.

RESULTS

During the 5-year study period, 7,367 patients (median age, 42 years; <18 years old, 23.3%) met the inclusion criteria. The most common anaphylaxis trigger was unspecified (56.2%), followed by food (25.3%), medication (14.6%), and venom (3.9%). Overall, 3.0% of patients had an additional anaphylaxis-related ED visit within 1 year (3.61 episodes per 100 patient-years). On multivariable analysis, risk factors associated with anaphylaxis recurrence were food trigger (odds ratio [OR], 2.31; 95% confidence interval [CI], 1.34-3.99), history of asthma (OR, 1.30; 95% CI, 1.13-1.51), and intensive care unit admission at the index anaphylaxis event (OR, 1.95; 95% CI, 1.41-2.69).

CONCLUSION

In this contemporary cohort study, history of asthma, food trigger, and greater index anaphylaxis severity, as measured by intensive care unit admission, were associated with a higher likelihood of a recurrent anaphylaxis-related ED visit within 1 year.

Maternal and early-life vitamin D deficiency enhances allergic reaction in an ovalbumin-sensitized BALB/c mouse model

Background

Recent studies have shown that vitamin D deficiency may contribute to the high prevalence of food allergy but the underlying mechanisms are far from clear.

Objective

The present study was designed to investigate the effect of maternal and early-life vitamin D deficiency in the development of food allergy.

Design

BALB/c mice were treated with ovalbumin (OVA) to trigger allergic reactions, under vitamin D-deficient (by maternal and early-life feeding of vitamin D deprived chow diet) or vitamin D-sufficient conditions.

Results

Increased occurrence and severity of allergic diarrhea as well as decreased rectal temperature were observed after OVA sensitization. For vitamin D deficiency groups, OVA-specific IgE and IL-4 levels were significantly increased, while IFN-γ levels were unchanged. Vitamin D deficiency also attenuated the structure of small intestinal villi and decreased the expression of the tight junction protein between adjacent epithelial cells and the percentages of CD4⁺CD25⁺Foxp3⁺Treg cell in spleen and mesenteric lymph nodes.

Conclusions

Maternal and early-life vitamin D deficiency have notable influence on the susceptibility to food allergy, which may relate with the reduced population of Treg cell and the dysfunction of intestinal epithelial barrier.

Children Covered by Medicaid/State Children's Health Insurance Program More Likely to Use Emergency Departments for Food Allergies

BACKGROUND

Food allergies (FAs) occur in 4% to 8% of children in the United States, and emergency department (ED) visits account for up to 20% of their costs. In 2010, the National Institute of Allergy and Infectious Diseases established diagnostic criteria and management practices for FAs, and recognition and treatment of FAs for pediatric ED practitioners has been described.

OBJECTIVE

This study identified trends and factors related to ED visits for pediatric FAs in the United States from 2001 to 2010. It was hypothesized that FAs increased and that differences existed in ED utilization based on age, insurance status, and geography. Low concordance with treatment guidelines for FAs was expected.

METHODS

Multivariate logistic regression, using National Hospital Ambulatory Medical Care Survey data, estimated factors associated with ED visits and treatment of FAs and nonspecific allergic reactions. Trends and treatment patters used weighted frequencies to account for the complex 4-stage probability survey design.

RESULTS

An estimated 239,303 (95% confidence interval [CI], 180,322-298,284) children visited the ED for FAs, demonstrating a significant rate increase during the period (53.08, P < 0.001). Logistic regression showed that the odds of ED visits for FAs were significantly associated with Medicaid/State Children's Health Insurance Program insurance (OR, 1.65 [95% CI, 1.01-2.69], P = 0.04), adolescents (OR, 1.92 [95% CI, 1.10-3.35], P = 0.02), and boys (OR, 1.55 [95% CI, 1.03-2.35], P = 0.04). Treatment with epinephrine for anaphylaxis diagnoses occurred in 57.4% of visits (95% CI, 42.3%-66.8%).

CONCLUSIONS

Medicaid/State Children's Health Insurance Program-insured pediatric patients had higher odds of visiting ED for recognized FAs and nonspecific allergic reactions and higher odds of receiving epinephrine than privately insured children.

Epidemiology of Food Allergy

Understanding the epidemiology of food allergy is complicated by the difficulty of identifying it on a large scale. The prevalence of food allergy is higher in younger age groups and decreases with age. Allergy to peanut and egg seems to be more common in Northern Europe, the United States, Canada and Australia compared with Southern Europe, Eastern Europe and Asia, whereas shellfish and fish allergies may be more common in Asia. The rate of transient unrecognized food allergy may be high and variable recognition of food allergy may explain some of the differences seen in food allergy prevalence.

Prevention of food allergy

The past few decades have witnessed an increase in the prevalence of IgE-mediated food allergy (FA). For prevention strategies to be effective, we need to understand the causative factors underpinning this rise. Genetic factors are clearly important in the development of FA, but given the dramatic increase in prevalence over a short period of human evolution, it is unlikely that FA arises through germline genetic changes alone. A plausible hypothesis is that 1 or more environmental exposures, or lack thereof, induce epigenetic changes that result in interruption of the default immunologic state of tolerance. Strategies for the prevention of FA might include primary prevention, which seeks to prevent the onset of IgE sensitization; secondary prevention, which seeks to interrupt the development of FA in IgE-sensitized children; and tertiary prevention, which seeks to reduce the expression of end-organ allergic disease in children with established FA. This review emphasizes the prevention of IgE-mediated FA through dietary manipulation, among other strategies; in particular, we focus on recent interventional studies in this field.

Variation and Trends in Anaphylaxis Care in United States Children's Hospitals

OBJECTIVES

We sought to determine the extent of variation in treatment of children with anaphylaxis.

METHODS

We identified children 1 month to 18 years of age presenting with a primary diagnosis of anaphylaxis to one of the 35 pediatric hospitals included in the Pediatric Health Information System between January 1, 2009, and September 30, 2013. We evaluated the variation in use of β2 agonists, glucocorticoids, histamine-1 (H1) antagonists, histamine-2 (H2) antagonists, inhaled epinephrine, intravenous fluids, and oxygen. We assessed whether variation exists in the rates of hospitalization and 3-day emergency department (ED) revisits and whether a temporal trend exists in the ED visit rate for anaphylaxis.

RESULTS

Among 10,351 children with anaphylaxis, the hospital-level median use of common anaphylaxis therapies varied for β2 agonists (22%, interquartile range [IQR] = 16%-26%), glucocorticoids (71%, IQR = 65%-76%), H1 blockers (60%, IQR = 57%-65%), H2 blockers (53%, IQR = 36%-64%), inhaled epinephrine (2.2%, IQR = 1.3%-3.5%), intravenous fluids (26%, IQR = 13%-41%), and oxygen (2.6%, IQR = 0.8%-4.1%). Hospitalization rates ranged from 12% to 95%, with a median rate of 41%. Anaphylaxis diagnoses rose from 5.7 to 11.7 patients per 10,000 ED visits between 2009 and 2013 (p < 0.001 for trend).

CONCLUSIONS

There is substantial variability in the use of common therapies and hospitalization rates for children cared for in U.S. children's hospitals. Additionally, ED visits for children with anaphylaxis are increasing at U.S. children's hospitals. These findings highlight the need for research defining optimal care for anaphylaxis.

Sunlight, vitamin D and food allergy

PURPOSE OF REVIEW

The role of vitamin D in the development of food allergy is unclear. We summarize recent data on the epidemiologic link between sunlight (UVB) and food allergy, and evidence for and against a specific role for vitamin D status.

RECENT FINDINGS

Since 2007, most epidemiologic studies have supported low sunlight (as measured by season of birth and latitude) as a risk factor for food allergy. Investigators have also looked directly at vitamin D status (as measured by serum 25OHD level) and its potential role. Although conflicting, the vitamin D studies suggest a more complicated association than a linear dose response in all individuals, with some studies indicating different associations based on host characteristics (e.g. concominant eczema, genetic polymorphisms, country of birth). Most studies have not fully examined the myriad effects of sunlight but have instead focused on a single maternal, neonatal or childhood 25OHD level.

SUMMARY

Many studies have linked sunlight with the development of food allergy but whether this is directly related to vitamin D status or a myriad of other sunlight-derived, seasonal and/or geographic factors remains uncertain. More studies are needed to investigate the role of sunlight and vitamin D status in food allergy because of their potential for primary prevention and disease modification.

Regional differences in vitamin D levels and incidence of food-induced anaphylaxis in South Korea

BACKGROUND

Previous studies have suggested low vitamin D as a potential risk factor for food allergy/anaphylaxis. However, few studies have investigated the association between vitamin D and food-induced anaphylaxis (FIA) in South Korea.

OBJECTIVE

To examine regional differences in serum vitamin D levels and FIA incidence.

METHODS

We used nationwide data collected from 2011 to 2013. Data on vitamin D were obtained from the Korea National Health and Nutrition Examination Survey; data on FIA were obtained from the Health Insurance and Assessment Service. Districts were grouped into region 1 (lower solar radiation) and region 2 (higher solar radiation). We examined differences in FIA incidence and vitamin D levels between the regions, adjusting for age.

RESULTS

The study included 2,814 patients with FIA and 15,367 people with available serum vitamin D measurements. Age-adjusted FIA incidence was 2.2 per 100,000 person-years in region 1 and 1.8 per 100,000 person-years in region 2 (relative risk, 1.23; 95% confidence interval, 1.09-1.39). Age-adjusted serum vitamin D levels were 16.5 ng/mL in region 1 and 17.8 ng/mL in region 2 (mean difference, 1.3 ng/mL; 95% confidence interval, 0.9-1.9). After stratification by age, sex, and area of residence, region 1 still had higher FIA incidence and lower vitamin D levels than region 2.

CONCLUSION

The present study found a higher incidence of FIA in regions with lower vitamin D levels in the population. Further investigation is necessary to identify any direct associations between vitamin D and food allergy/anaphylaxis.

The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D

Using a variety of approaches, researchers have studied the health effects of solar ultraviolet (UV) radiation exposure and vitamin D. This review compares the contributions from geographical ecological studies with those of observational studies and clinical trials. Health outcomes discussed were based on the author's knowledge and include anaphylaxis/food allergy, atopic dermatitis and eczema, attention deficit hyperactivity disorder, autism, back pain, cancer, dental caries, diabetes mellitus type 1, hypertension, inflammatory bowel disease, lupus, mononucleosis, multiple sclerosis, Parkinson disease, pneumonia, rheumatoid arthritis, and sepsis. Important interactions have taken place between study types; sometimes ecological studies were the first to report an inverse correlation between solar UVB doses and health outcomes such as for cancer, leading to both observational studies and clinical trials. In other cases, ecological studies added to the knowledge base. Many ecological studies include other important risk-modifying factors, thereby minimizing the chance of reporting the wrong link. Laboratory studies of mechanisms generally support the role of vitamin D in the outcomes discussed. Indications exist that for some outcomes, UVB effects may be independent of vitamin D. This paper discusses the concept of the ecological fallacy, noting that it applies to all epidemiological studies.

Why Does Australia Appear to Have the Highest Rates of Food Allergy?

Australia has reported the highest rates of food allergy, using the gold standard, oral food challenge. This phenomenon, which appears linked to the "modern lifestyle" and has coincided with the explosion of the new diseases of affluence in the 21st century, dubbed "affluenza," has spurred a multitude of theories and academic investigations. This review focuses on potentially modifiable lifestyle factors for the prevention of food allergy and presents the first data to emerge in the Australian context that centers around the dual allergen exposure hypothesis, the vitamin D hypothesis, and the hygiene hypothesis.

Pediatric emergency department visits and hospitalizations due to food-induced anaphylaxis in Illinois

BACKGROUND

Rates of food-induced anaphylaxis among children remain uncertain. In addition, little is known about the demographics of children who have experienced food-induced anaphylaxis resulting in emergency department (ED) visits and/or subsequent hospitalizations.

OBJECTIVES

To evaluate trends in ED visits and hospital admissions due to food-induced anaphylaxis among Illinois children and to identify socioeconomic variation in trend distribution.

METHODS

Illinois hospital discharge data compiled by the Illinois Hospital Association were used to identify ED visits or hospitalizations for food-induced anaphylaxis in Illinois hospitals from 2008-2012. Data for children aged 0 to 19 years who were Illinois residents and received a diagnosis of food-induced anaphylaxis based on International Classification of Diseases, Ninth Revision, Clinical Modification codes (995.60 through 995.69) were included for analysis.

RESULTS

There was a significant increase in the rate of ED visits and hospital admissions due to food-induced anaphylaxis among children in Illinois during the 5-year period, with an annual percent increase of 29.1% from 6.3 ED visits and hospital admissions per 100,000 children in 2008 to 17.2 in 2012 (P < .001). Increases in visit frequency were observed for all study variables, including age, sex, race/ethnicity, insurance type, metropolitan status, hospital type, and allergenic food. Visits were most frequent each year for Asian children and children with private insurance. However, the annual percent increase in visits was most pronounced among Hispanic children (44.3%, P < .001) and children with public insurance (30.2%, P < .001).

CONCLUSION

ED visits and hospital admissions for food-induced anaphylaxis have increased during a 5-year period among children in Illinois, regardless of race/ethnicity and socioeconomic status.

Glucocorticoids and Hospital Length of Stay for Children with Anaphylaxis: A Retrospective Study

OBJECTIVE

To evaluate whether glucocorticoid administration is associated with improved outcomes in children with anaphylaxis.

STUDY DESIGN

We included children from the Pediatric Health Information System database who were diagnosed with anaphylaxis at 35 US children's hospitals between 2009 and 2013. Patients were stratified by disposition from the emergency department (ED), either hospitalized or discharged. We evaluated the association between glucocorticoid administration and prolonged length of stay (LOS), defined as hospital stay ≥ 2 days, and subsequent epinephrine administration among hospitalized children. Among discharged children, we assessed the association between glucocorticoid administration and ED revisits within 3 days. Analyses were adjusted for illness severity using ordering of laboratory tests, medications, oxygen, intravenous fluids, and admission to the intensive care unit.

RESULTS

Among 5203 children hospitalized with anaphylaxis, 424 (8.2%) had prolonged LOS. Glucocorticoid administration was inversely associated with prolonged LOS (aOR, 0.61; 95% CI, 0.41-0.93) and with subsequent epinephrine use (aOR, 0.63; 95% CI, 0.43-0.84) among hospitalized children. Glucocorticoid administration was not associated with the odds of a 3-day revisit (aOR, 1.01; 95% CI, 0.50-2.05) among discharged patients.

CONCLUSION

The use of glucocorticoids was inversely associated with prolonged LOS among children hospitalized with anaphylaxis, but was not associated with 3-day ED revisits among discharged children. These findings support the use of glucocorticoids in children hospitalized with anaphylaxis.

Anaphylaxis to food

This article provides a clinically focused review of food-induced anaphylaxis that includes epidemiology, risk factors, allergens, diagnosis, and management. Currently, there is no treatment for food allergy. Dietary avoidance and emergency preparedness are the cornerstones of management. Effective and safe therapies to reduce the risk of serious food-induced reactions are urgently needed, as are reliable biomarkers to predict severity.

Higher latitude and lower solar radiation influence on anaphylaxis in Chilean children

BACKGROUND

Recent studies suggest an association between higher latitude, a proxy of vitamin D (VD) status, and allergic diseases. Chile provides an ideal setting to study this association due to its latitude span and high rates of VD deficiency in southern regions. The aim of this study is to explore the associations of latitude and solar radiation with anaphylaxis admission rates.

METHODS

We reviewed anaphylaxis admissions in Chile's hospital discharge database between 2001 and 2010 and investigated associations with latitude and solar radiation.

RESULTS

2316 anaphylaxis admissions were registered. Median age of patients was 41 yr; 53% were female. National anaphylaxis admission rate was 1.41 per 100,000 persons per year. We observed a strong north-south increasing gradient of anaphylaxis admissions (β 0.04, p = 0.01), with increasing rates south of latitude 34°S. A significant association was also observed between solar radiation and anaphylaxis admissions (β -0.11, p = 0.009). Latitude was associated with food-induced (β 0.05, p = 0.02), but not drug-induced (β -0.002, p = 0.27), anaphylaxis. The association between latitude and food-induced anaphylaxis was significant in children (β 0.01, p = 0.006), but not adults (β 0.003, p = 0.16). Anaphylaxis admissions were not associated with regional sociodemographic factors like poverty, rurality, educational level, ethnicity, or physician density.

CONCLUSIONS

Anaphylaxis admission rates in Chile are highest at higher latitudes and lower solar radiation, used as proxies of VD status. The associations appear driven by food-induced anaphylaxis. Our data support a possible role of VD deficiency as an etiological factor in the high anaphylaxis admission rates found in southern Chile.

Peanut, milk, and wheat intake during pregnancy is associated with reduced allergy and asthma in children

BACKGROUND

Maternal diet during pregnancy may affect childhood allergy and asthma.

OBJECTIVE

We sought to examine the associations between maternal intake of common childhood food allergens during early pregnancy and childhood allergy and asthma.

METHODS

We studied 1277 mother-child pairs from a US prebirth cohort unselected for any disease. Using food frequency questionnaires administered during the first and second trimesters, we assessed maternal intake of common childhood food allergens during pregnancy. In mid-childhood (mean age, 7.9 years), we assessed food allergy, asthma, allergic rhinitis, and atopic dermatitis by questionnaire and serum-specific IgE levels. We examined the associations between maternal diet during pregnancy and childhood allergy and asthma. We also examined the cross-sectional associations between specific food allergies, asthma, and atopic conditions in mid-childhood.

RESULTS

Food allergy was common (5.6%) in mid-childhood, as was sensitization to at least 1 food allergen (28.0%). Higher maternal peanut intake (each additional z score) during the first trimester was associated with 47% reduced odds of peanut allergic reaction (odds ratio [OR], 0.53; 95% CI, 0.30-0.94). Higher milk intake during the first trimester was associated with reduced asthma (OR, 0.83; 95% CI, 0.69-0.99) and allergic rhinitis (OR, 0.85; 95% CI, 0.74-0.97). Higher maternal wheat intake during the second trimester was associated with reduced atopic dermatitis (OR, 0.64; 95% CI, 0.46-0.90). Peanut, wheat, and soy allergy were each cross-sectionally associated with increased childhood asthma, atopic dermatitis, and allergic rhinitis (ORs, 3.6 to 8.1).

CONCLUSION

Higher maternal intake of peanut, milk, and wheat during early pregnancy was associated with reduced odds of mid-childhood allergy and asthma.

Food allergy diagnosis and therapy: where are we now?

Food allergy is a growing worldwide epidemic that adversely effects up to 10% of the population. Causes and risk factors remain unclear and diagnostic methods are imprecise. There is currently no accepted treatment for food allergy. Therefore, there is an imminent need for greater understanding of food allergies, revised diagnostics and development of safe, effective therapies. Oral immunotherapy provides a particularly promising avenue, but is still highly experimental and not ready for clinical use.

Racial and ethnic disparity in food allergy in the United States: a systematic review

BACKGROUND

The prevalence of food allergy is rising among US children. Little is known about racial/ethnic disparities in food allergy.

OBJECTIVE

We performed a systematic literature review to understand racial/ethnic disparities in food allergy in the United States.

METHODS

We searched PubMed/MEDLINE, Embase, and Scopus for original data about racial/ethnic disparities in the diagnosis, prevalence, treatment, or clinical course of food allergy or sensitization, with a particular focus on black (African American) race. Articles were analyzed by study methodology, racial/ethnic composition, food allergy definition, outcomes, summary statistic used, and covariate adjustment.

RESULTS

Twenty of 645 identified articles met inclusion criteria. The studies used multiple differing criteria to define food allergy, including self-report, sensitization assessed by serum food-specific IgE to selected foods without corroborating history, discharge codes, clinic chart review, and event-reporting databases. None used oral food challenge. In 12 studies, black persons (primarily children) had significantly increased adjusted odds of food sensitization or significantly higher proportion or odds of food allergy by self-report, discharge codes, or clinic-based chart review than white children. Major differences in study methodology and reporting precluded calculation of a pooled estimate of effect.

CONCLUSION

Sparse and methodologically limited data exist about racial/ethnic disparity in food allergy in the United States. Available data lack a common definition for food allergy and use indirect measures of allergy, not food challenge. Although data suggest an increased risk of food sensitization, self-reported allergy, or clinic-based diagnosis of food allergy among black children, no definitive racial/ethnic disparity could be found among currently available studies.

Effects of vitamin D on immune disorders with special regard to asthma, COPD and autoimmune diseases: a short review

This paper reviews the recent data on the role of vitamin D (VD) in the genesis of various immunological disorders. It inhibits immune reactions in general, but it enhances the transcription of 'endogenous antibiotics' such as cathelicidin and defensins. VD inhibits the genesis of both Th1- and Th2-cell mediated diseases. The pleiotropic character VD-induced effects are due to the altered transcription of hundreds of genes. VD supplementation in most related studies reduced the prevalence of asthma. Th1-dependent autoimmune diseases (e.g., multiple sclerosis, Type 1 diabetes, Crohn's disease, rheumatoid arthritis and so on) are also inhibited by VD due to inhibition of antigen presentation, reduced polarization of Th0 cells to Th1 cells and reduced production of cytokines from the latter cells. VD seems to also be a useful adjunct in the prevention of allograft rejection. Last but not least, VD supplementation may be useful in the prevention or adjunct treatment of chronic obstructive pulmonary disease.

Food allergy: temporal trends and determinants

This review summarizes studies discussing temporal trends in the prevalence of food allergy as well as potential factors associated with the development of food allergy. In addition, we will address the potential hypotheses accounting for the apparent increase in food allergy prevalence. Studies suggest increased prevalence of food allergy. However, relatively little is known about its pathogenesis. This review aims to assess temporal trends in the prevalence of food allergy and discuss potential genetic, environmental, and demographic determinants. The search strategy examined the medical literature database MEDLINE (using PubMed) for the time period of January 1, 2002 to January 31, 2012. In recent decades, the prevalence of food allergy in general has increased by 0.60 % [95 % confidence interval (CI), 0.59 %-0.61 %] and the prevalence of peanut allergy by 0.027 % (95 % CI, 0.026 %-0.028 %), but it has now likely stabilized in developed countries. Genes, the environment, and demographic characteristics play a role in the pathogenesis of food allergy. Numerous environmental and demographic factors as well as gene-environment interactions may account for this increase in prevalence, but further studies are required to tease out their relative contribution.

Comparison of the incidence, etiology, and management of anaphylaxis over time

BACKGROUND

Failure to promptly recognize and treat anaphylaxis can result in death. Understanding the incidence, etiology, and management is imperative. A previous pediatric study identified latex as the most common anaphylaxis allergen. We aim to describe the incidence, etiology, and management of anaphylaxis prelatex and postlatex-precaution implementation.

METHODS

Retrospective review of inpatient and emergency department (ED) records of pediatric anaphylaxis patients seen at 1 institution between 1986 and 1990 or 2002 and 2006 was performed. Patients with 2 systemic symptoms (gastrointestinal, respiratory, hypotension/syncope, oropharyngeal, altered mental status) or 1 systemic symptom plus 1 cutaneous symptom (urticaria, edema, or flushing) were included.

RESULTS

Fifty-three episodes were included from 1986 to 1990. A total of 117 episodes were included from 2002 to 2006. Approximately 80% of cases presented to the ED. From 1986 to 1990, we noted 30.5 cases per 100,000 ED visits versus 38 cases per 100,000 ED visits from 2002 to 2006. Food allergens were most common in both groups (43%). Latex accounted for only 1.9% of cases in 1986 to 1990 versus 1.7% postlatex precautions. Prehospital epinephrine use was poor. Patients in 2002 to 2006 were more likely to receive steroids, H2-blockers, epinephrine autoinjectors, and allergist referrals but less likely to receive epinephrine.

CONCLUSIONS

The etiology of pediatric anaphylaxis has not significantly changed over time but seems to differ across regions because latex was not a significant allergen at this institution in either period. The incidence of anaphylaxis has increased slightly. Anaphylaxis remains underdiagnosed and undertreated. Improved education of patients/caregivers and health care providers is needed.

Racial disparities in allergic outcomes in African Americans emerge as early as age 2 years

BACKGROUND

Racial disparities in allergic disease outcomes have been reported with African Americans suffering disproportionately compared to White individuals.

OBJECTIVE

To examine whether or not racial disparities are present as early as age 2 years in a racially diverse birth cohort in the Detroit metropolitan area.

METHODS

All children who were participants in a birth cohort study in the Detroit metropolitan area were invited for a standardized physician exam with skin prick testing and parental interview at age 2 years. Physicians made inquiries regarding wheezing and allergy symptoms and inspected for and graded any atopic dermatitis (AD). Skin testing was performed for Alternaria, cat, cockroach, dog, Dermatophagoides farinae (Der F), Short Ragweed, Timothy grass, egg, milk and peanut. Specific IgE was measured for these same allergens and total IgE was determined.

RESULTS

African American children (n = 466) were more likely than White children (n = 223) to have experienced any of the outcomes examined: at least 1 positive skin prick test from the panel of 10 allergens (21.7% vs. 11.0%, P = 0.001); at least one specific IgE ≥ 0.35 IU/mL (out of a panel of 10 allergens) (54.0% vs. 42.9%, P = 0.02); had AD (27.0% vs. 13.5%, Chi-square P < 0.001); and to ever have wheezed (44.9% vs. 36.0%, P = 0.03). African American children also tended to have higher total IgE (geometric means 23.4 IU/mL (95%CI 20.8, 27.6) vs. 16.7 IU/mL (95%CI 13.6, 20.6 IU/mL), Wilcoxon Rank Sum P = 0.004). With the exception of wheezing, the associations did not vary after adjusting for common social economic status variables (e.g. household income), environmental variables (endotoxin; dog, cat and cockroach allergen in house dust) or variables that differed between the racial groups (e.g. breastfeeding). After adjustment, the wheeze difference was ameliorated.

CONCLUSIONS

With disparities emerging as early as age 2 years, investigations into sources of the disparities should include the prenatal period and early life.

Geographic variability of childhood food allergy in the United States

OBJECTIVE

The aim of this study was to describe the distribution of childhood food allergy in the United States.

METHODS

A randomized survey was administered electronically from June 2009 to February 2010 to adults in US households with at least 1 child younger than 18 years. Data were analyzed as weighted proportions to estimate prevalence and severity of food allergy by geographic location. Multiple logistic regression models were constructed to estimate the association between geographic location and food allergy.

RESULTS

Data were analyzed for 38 465 children. Increasing population density corresponded with increasing prevalence, from 6.2% in rural areas (95% confidence interval [CI] = 5.6-6.8) to 9.8% in urban centers (95% CI = 8.6-11.0). Odds of food allergy were graded, with odds in urban versus rural areas highest (odds ratio [OR] = 1.7, 95% CI = 1.5-2.0), followed by metropolitan versus rural areas (OR = 1.4, 95% CI = 1.2-1.5), and so on. Significance remained after adjusting for race/ethnicity, gender, age, household income, and latitude.

CONCLUSIONS

An association between urban/rural status and food allergy prevalence was observed.

Sensitization and allergic histories differ between black and white pregnant women

BACKGROUND

Racial differences in allergic diseases have been reported, with black subjects suffering disproportionately compared with white subjects, although such studies have been more commonly done in pediatric populations.

OBJECTIVE

We sought to determine whether there are differences in rates of allergic sensitization or prior diagnoses of asthma, hay fever, or eczema in black and white pregnant women.

METHODS

Women were recruited during pregnancy (regardless of allergic history) as part of a birth cohort study in the Detroit metropolitan area and were interviewed about prior doctors' diagnoses of asthma, hay fever/nasal allergies/allergic rhinitis, and eczema. Blood samples were collected, total IgE levels were determined, and specific IgE levels were measured for Alternaria alternata, cat, cockroach, dog, Dermatophagoides farinae, short ragweed, timothy grass, and egg.

RESULTS

Black women (n = 563) were more likely than white women (n = 219) to have had at least 1 specific IgE level of 0.35 IU/mL or greater (62.5% vs 40.2%, P < .001). Black women had higher total IgE levels (geometric mean, 47.8 IU/mL [95% CI, 42.5-53.8 IU/mL] vs 20.0 IU/mL [95% CI, 16.2-24.6 IU/mL]; P < .001, Wilcoxon rank sum test). Black women were more likely to have had a prior doctor's diagnosis of asthma (22.7% vs 16.0%, P = .04) and eczema (21.9% vs 14.8%) but not hay fever (white women: 17.5% vs black women: 15.7%, P = .55). Associations persisted for total IgE levels, having 1 or more positive allergen-specific IgE levels, and eczema after adjusting for common socioeconomic or environmental variables.

CONCLUSIONS

Racial differences in allergic sensitization and diagnoses were present, even after controlling for various factors. Future research should focus on prevention to ameliorate these disparities.

Early life precursors, epigenetics, and the development of food allergy

Food allergy (FA), a major clinical and public health concern worldwide, is caused by a complex interplay of environmental exposures, genetic variants, gene-environment interactions, and epigenetic alterations. This review summarizes recent advances surrounding these key factors, with a particular focus on the potential role of epigenetics in the development of FA. Epidemiologic studies have reported a number of nongenetic factors that may influence the risk of FA, such as timing of food introduction and feeding pattern, diet/nutrition, exposure to environmental tobacco smoking, prematurity and low birth weight, microbial exposure, and race/ethnicity. Current studies on the genetics of FA are mainly conducted using candidate gene approaches, which have linked more than 10 genes to the genetic susceptibility of FA. Studies on gene-environment interactions of FA are very limited. Epigenetic alteration has been proposed as one of the mechanisms to mediate the influence of early life environmental exposures and gene-environment interactions on the development of diseases later in life. The role of epigenetics in the regulation of the immune system and the epigenetic effects of some FA-associated environmental exposures are discussed in this review. There is a particular lack of large-scale prospective birth cohort studies that simultaneously assess the interrelationships of early life exposures, genetic susceptibility, epigenomic alterations, and the development of FA. The identification of these key factors and their independent and joint contributions to FA will allow us to gain important insight into the biological mechanisms by which environmental exposures and genetic susceptibility affect the risk of FA and will provide essential information to develop more effective new paradigms in the diagnosis, prevention, and management of FA.

The role of vitamin D in the immunopathogenesis of allergic skin diseases

Vitamin D plays key roles in innate and adaptive immunity through the stimulation of Toll-like receptors, increasing pro-inflammatory cytokine production, and possibly enhancing T helper type 2 responses. These mechanisms may explain the growing body of evidence connecting vitamin D to allergic diseases, including asthma, food allergies, and allergic rhinitis. The data relating vitamin D to allergic skin diseases are equivocal with studies linking both high and low vitamin D levels to an increased risk of developing atopic dermatitis. In this paper, we describe the role of vitamin D in the immunopathogenesis of atopic dermatitis and other allergic skin diseases.

An update on epidemiology of anaphylaxis in children and adults

PURPOSE OF REVIEW

The purpose of the present review is to describe the epidemiology of food-induced, medication-induced, drug-induced, and insect sting-induced anaphylaxis; to summarize recent changes in the incidence of anaphylaxis internationally; and to discuss recent insights into potential risk factors for anaphylaxis.

RECENT FINDINGS

Recent studies confirm that the incidence of anaphylaxis, particularly food-induced anaphylaxis, is increasing world-wide. The rise in anaphylaxis incidence appears most pronounced in children under the age of 5 years, which is also the age group most at risk of hospitalization for food-induced anaphylaxis. Identification of factors that may increase the risk of episodes of anaphylaxis remains an important research priority. Recently, two large cohort studies using data from electronic medical records confirmed that individuals with asthma are at higher risk of anaphylaxis and those with severe asthma have the highest risk of all. With respect to modifiable lifestyle factors, several studies have demonstrated a link between latitude and anaphylaxis, with areas with less year-round sunlight reporting a higher prevalence of food-induced anaphylaxis.

SUMMARY

Reports of an increasing incidence of anaphylaxis internationally highlight the need for identification of modifiable risk factors for anaphylaxis. Emerging evidence suggests that low vitamin D levels may be associated with risk of anaphylaxis and food allergy; however, further studies are required to confirm this.

Asthma, allergy and respiratory infections: the vitamin D hypothesis

The recent discovery that every tissue in the human body has vitamin D receptors and that vitamin D has pleiotropic effects has prompted an increased interest in this hormone. Vitamin D deficiency is widespread and on the increase. There is no consensus on the serum vitamin D levels to consider appropriate for global health, the cutoffs for its deficiency, or the doses to use for its supplementation. Vitamin D seems to correlate closely with host reactions against various respiratory infections. Epidemiological studies have shown that low serum 25-hydroxyvitamin D levels are associated with a higher risk of upper and lower respiratory infections in children and a shortage of vitamin D may contribute to asthmatic patients' symptoms and morbidity rates. There are studies highlighting associations between childhood asthma, fetal lung and/or immune development, and maternal vitamin D intake. An insufficiency of this vitamin also seems to be implicated in the onset of childhood atopy and food allergies. The hypothesis is that vitamin D could have a central role in these pathological situations and that it may represent a novel preventive and/or therapeutic strategy. This article reviews and discusses published data on the relationship between vitamin D and asthma and allergy, emphasizing the need for controlled, prospective studies on vitamin D supplementation to clarify whether it has a role in the prevention of and treatment for asthma and allergic conditions.

Strategies to prevent or reduce allergic disease

The need for allergy prevention strategies has never been greater. Surging rates of food allergy and eczema are now adding to the already substantial burden of asthma and respiratory allergic diseases. The parallel rise in many other immune diseases suggests that the developing immune system is highly vulnerable to modern environmental changes. These strong environmental pressures may be one reason why simple allergen avoidance strategies have not been successful. Another more recent strategy to curtail the allergy epidemic has been to identify factors associated with modern lifestyle that may be causally linked with allergic disease, in an attempt to restore more favourable conditions for immune tolerance during early development. More hygienic conditions and disruption of microbial exposure have prompted strategies to restore this balance using probiotic and prebiotic supplements. Modern dietary changes linked with allergic diseases have prompted supplementation studies to assess the preventive merits of specific immunomodulatory dietary nutrients such as polyunsaturated fatty acids. Other nutrients such as antioxidants, folate, and vitamin D are also currently under investigation. Modern environmental pollutants have also been associated with adverse effects on immune development and the risk of disease. While many of these avenues have provided some promise, they have not yet translated into specific recommendations. Current evidence-based guidelines for allergy prevention remain limited to avoidance of cigarette smoke, promotion of breastfeeding and the use of hydrolysed formula when breastfeeding is not possible. Allergen avoidance strategies have been largely removed from most guidelines. It is hoped that a number of ongoing studies will help provide clearer recommendations around the use of probiotics, prebiotics, specific dietary nutrients and the role of early introduction of allergenic foods for the promotion of tolerance. Despite the current uncertainties, prevention remains the best long-term strategy to reduce the growing burden of allergic disease.

A population-based epidemiologic study of emergency department visits for anaphylaxis in Florida

BACKGROUND

Previous population-based analyses of emergency department (ED) visits for anaphylaxis have been limited to small populations in limited geographic areas and focused on children or have included patients who had allergic conditions other than anaphylaxis.

OBJECTIVE

We sought to describe the epidemiology and risk factors among patients with anaphylaxis presenting to Florida EDs.

METHODS

Two thousand seven hundred fifty-one patients with anaphylaxis were identified for 2005-2006 within ED records by using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), and a validated ICD-9-CM-based algorithm. Age- and sex-specific rates were calculated. Regression analyses were used to determine relative risks for anaphylaxis caused by various triggers (food, venom, and medication) and risk factors (age, sex, race, and ethnicity).

RESULTS

The highest observed rates were among the youngest male subjects (8.2/100,000 Floridians aged 0-4 years) and among adult female subjects (15-54 years) grouped in 10-year age categories (9.9-10.9/100,000 Floridians). Male and black subjects were 20% and 25%, respectively, more likely to have a food trigger than female and white subjects. White, male, and older subjects were more likely to have an anaphylaxis-related ED visit caused by insect stings. Venom-induced anaphylaxis was more likely in August through October. Children were less likely than those older than 70 years (referent) to have medication-induced anaphylaxis (P < .03).

CONCLUSION

This is the only ED-based population study in a US lower-latitude state. The overall rate is considerably lower than other US ED-based population studies. The rates of anaphylaxis by age group differed by sex. Male and black subjects were more likely to have a food trigger.

Perspectives on anaphylaxis epidemiology in the United States with new data and analyses

Anaphylaxis incidence rates and time trends in the United States have been reported using different data sources and selection methods. Larger studies using diagnostic coding have inherent limitations in sensitivity and specificity. In contrast, smaller studies using chart reviews, including reports from single institutions, have better case characterization but suffer from reduced external validity due to their restricted nature. Increasing anaphylaxis hospitalization rates since the 1990s have been reported abroad. However, we report no significant overall increase in the United States. There have been several reports of increasing anaphylaxis rates in northern populations in the United States, especially in younger people, lending support to the suggestion that higher anaphylaxis rates occur at higher latitudes. We analyzed anaphylaxis hospitalization rates in comparably sized northern (New York) and southern (Florida) states and found significant time trend differences based on age. This suggests that the relationship of latitude to anaphylaxis incidence is complex.

Asthma prevalence associated with geographical latitude and regional insolation in the United States of America and Australia

BACKGROUND

It has been proposed that vitamin D deficiency may be responsible for an increase in the prevalence of allergic diseases and asthma worldwide. Human ability to generate physiologically required quantities of vitamin D through sun exposure is decreasing with increasing geographical latitude.

OBJECTIVES

Considering that vitamin D deficiency is usually due to lack of outdoor sun exposure, this study is designed to test the hypothesis that a higher prevalence of asthma should be expected at high relative to low geographical latitudes.

METHODS

Linear regression analyses are performed on asthma prevalence in the U.S. adult population vs. geographical latitude, insolation, air temperature, and air pollution (PM(2.5)) for 97 major metropolitan/micropolitan statistical areas of the continental United States of America and on general population asthma prevalence vs. geographical latitude in eight metropolitan areas of Australia.

RESULTS

A 10° change in geographical latitude from southern to northern regions of the Eastern Seaboard is associated with a 2% increase in adult asthma prevalence (p<0.001). Total insolation in winter months is almost as strong as latitude in its ability to explain the observed spatial variation in the prevalence of asthma (r(2) = 0.43; p<0.001). Similar results are obtained using the Australian data (r(2) = 0.73; p<0.01), suggesting a consistent association between the latitude/insolation and asthma prevalence worldwide.

CONCLUSIONS

The results of this study suggest that, as a known modulator of the immune response closely linked with the geographical latitude and erythemal UV irradiation, vitamin D may play an important role in the development/exacerbation of asthma.

Can food allergy be prevented? The current evidence

Food allergy is a recognized public health concern, for which preventative strategies are required. Although an intervention that adequately protects against the development of food allergy has still to be identified, limited benefits have been shown for the prevention of related allergic conditions such as eczema, and to a lesser extent asthma and rhinitis; these benefits are usually limited to at-risk populations. Prevention strategies need to be tested using randomized controlled study designs that account for the numerous methodological challenges, safety concerns, and necessary ethical limitations.