Dietary gluten avoidance in Canada: a cross-sectional study using survey data

BACKGROUND

A gluten-free diet (GFD) is required for the management of some conditions, whereas some Canadians may follow a GFD for discretionary reasons. We sought to estimate the prevalence of Canadians who adhere to a GFD, identify factors associated with adherence to a GFD, and describe and compare the location of food preparation and consumption for those who follow a GFD, those who report no dietary avoidances and those reporting other dietary avoidances.

METHODS

We used cross-sectional data from the 2015 Canadian Community Health Survey - Nutrition (n = 20 487). Demographic variables included sex, age group, ethnicity, highest level of household education and income adequacy. The relations between respondent characteristics and report of a GFD were estimated using logistic regression. Respondents were further categorized as avoiding dietary gluten, other dietary avoidances and no dietary avoidances.

RESULTS

An estimated 1.9% of Canadians follow a GFD. Women had 2 times higher odds (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.32 to 3.27) of reporting a GFD than men. After adjustment for income adequacy, household education, sex, age group and ethnicity, residents of Ontario and Quebec had about half the odds (OR 0.52, 95% CI 0.31 to 0.87, and OR 0.55, 95% CI 0.32 to 0.94, respectively) of reporting a GFD compared with residents of Atlantic Canada. Canadians who followed a GFD consumed significantly fewer calories from foods prepared at restaurants than both Canadians who reported no dietary avoidances and those who reported dietary avoidances other than gluten. Canadians following a GFD reported that 2.0% (95% CI 1.1% to 2.9%) of their daily kilocalories were from foods prepared at restaurants, compared with 6.7% (95% CI 5.4% to 7.9%) for Canadians reporting 1 or more dietary avoidances other than gluten, and 6.4% (95% CI 6.0% to 6.9%) for those reporting no avoidances.

INTERPRETATION

The estimated 1.9% prevalence of dietary gluten avoidance likely includes individuals with celiac disease, wheat allergies and nonceliac gluten sensitivity, as well as individuals excluding gluten in the management of irritable bowel syndrome or for reasons related to dietary trends. Canadians eating GFDs consume fewer daily calories from restaurant-prepared foods than other Canadians, which may have social implications.

Prevalence of Wheat/Gluten-Related Disorders and Gluten-Free Diet in Paraguay: An Online Survey-Based Study

Gluten-related disorders (GRDs) are increasing around the world, but their magnitude and relevance remain unknown in most Latin American countries. Thus, an online survey was conducted to estimate the prevalence of GRDs as well as adherence to a gluten-free diet (GFD) in Paraguayan adult population. There were 1058 individuals surveyed using a validated questionnaire (response rate of 93.9%). The self-reported prevalence rates were as follows (95% CI): gluten sensitivity (GS), 10.30% (8.53-12.29); non-celiac GS (NCGS), 5.19% (3.94-6.71); physician-diagnosed celiac disease (PD-CD), 3.11% (2.15-4.35); wheat allergy (WA), 2.07% (1.30-3.13); and adherence to GFD, 15.69% (13.55-18.02). Excluding CD, more women than men met the criteria for GRDs, adverse food reactions, and GFD (p < 0.05). Eight respondents reported the coexistence of NCGS with PD-CD and/or WA. Most cases on a GFD indicated medical/dietitian advice for following the diet (68.07%). Non-self-reported GS individuals indicated weight control (46.4%) and the notion that the GFD is healthier (20.2%) as the main motivations for following the diet. GRDs are not uncommon in Paraguayan adult population. It seems that there is awareness about GRDs and the GFD, but training about the diagnosis of GRDs is desirable because of the informed overlapping diagnoses of CD or WA with NCGS. Future studies involving face-to-face interviews are necessary.

Non-Celiac Gluten Sensitivity in the Context of Functional Gastrointestinal Disorders

Gluten-free diets are increasingly chosen in the Western world, even in the absence of a diagnosis of celiac disease. Around 10% of people worldwide self-report gluten-related complaints, including intestinal and extra-intestinal symptoms. In most cases, these subjects would be labeled as patients suffering from irritable bowel syndrome (IBS) who place themselves on a gluten-free diet even in the absence of celiac disease. In some instances, patients report a clear benefit by avoiding gluten from their diet and/or symptom worsening upon gluten reintroduction. This clinical entity has been termed non-celiac gluten sensitivity (NCGS). The symptoms referred by these patients are both intestinal and extra-intestinal, suggesting that similarly to functional gastrointestinal disorders, NCGS is a disorder of gut-brain interaction. It remains unclear if gluten is the only wheat component involved in NCGS. The mechanisms underlying symptom generation in NCGS remain to be fully clarified, although in the past few years, the research has significantly moved forward with new data linking NCGS to changes in gut motility, permeability and innate immunity. The diagnosis is largely based on the self-reported reaction to gluten by the patient, as there are no available biomarkers, and confirmatory double-blind challenge protocols are unfeasible in daily clinical practice. Some studies suggest that a small proportion of patients with IBS have an intolerance to gluten. However, the benefits of gluten-free or low-gluten diets in non-celiac disease-related conditions are limited, and the long-term consequences of this practice may include nutritional and gut microbiota unbalance. Here, we summarize the role of gluten in the clinical features, pathophysiology, and management of NCGS and disorders of gut-brain interaction.

Psychiatric Comorbidity in Children and Adults with Gluten-Related Disorders: A Narrative Review

Gluten-related disorders are characterized by both intestinal and extraintestinal manifestations. Previous studies have suggested an association between gluten-related disorder and psychiatric comorbidities. The objective of our current review is to provide a comprehensive review of this association in children and adults. A systematic literature search using MEDLINE, Embase and PsycINFO from inception to 2018 using terms of ‘celiac disease’ or ‘gluten-sensitivity-related disorders’ combined with terms of ‘mental disorders’ was conducted. A total of 47 articles were included in our review, of which 28 studies were conducted in adults, 11 studies in children and eight studies included both children and adults. The majority of studies were conducted in celiac disease, two studies in non-celiac gluten sensitivity and none in wheat allergy. Enough evidence is currently available supporting the association of celiac disease with depression and, to a lesser extent, with eating disorders. Further investigation is warranted to evaluate the association suggested with other psychiatric disorders. In conclusion, routine surveillance of potential psychiatric manifestations in children and adults with gluten-related disorders should be carried out by the attending physician.

Prevalence of Self-Reported Gluten-Related Disorders and Adherence to a Gluten-Free Diet in Salvadoran Adult Population

Gluten-related disorders are not considered of relevance at public health level in Central America. The prevalence of gluten-related disorders, and adherence to a gluten-free diet, remain unknown in the Central American region. We conducted a cross-sectional survey of the Central American population from San Salvador, El Salvador, to estimate the prevalence rates of self-reported gluten-related disorders and adherence to a gluten-free diet. 1326 individuals were surveyed. Self-reported prevalence rates were (95% Confidence Interval): gluten sensitivity 3.1% (2.3–4.2); physician-diagnosed celiac disease 0.15% (0.04–0.5); wheat allergy 0.75% (0.4–1.3); non-celiac gluten sensitivity 0.98% (0.5–1.6). The prevalence rate of adherence to a gluten-free diet was 7.0% (5.7–8.5). Seven self-reported physician diagnosed gluten-sensitive cases informed the co-existence of non-celiac gluten sensitivity with celiac disease and/or wheat allergy. Among the non-self-reported gluten sensitivity individuals following a gluten-free diet, 50% reported that they were seeing a health professional for gluten-free dietary advice. Gluten sensitivity is commonly reported in Salvadoran population, but some health professionals acknowledge the coexistence of wheat allergy, celiac disease, and non-celiac gluten sensitivity. Among studies at population level, the prevalence of adherence to a gluten-free diet in Salvadoran population is the highest reported until now. However, just a few of the gluten-free diet followers were doing it for health-related benefits; the others reported weight control and the perception that the diet is healthier as the main motivation for adopting such a diet.

Non-celiac gluten sensitivity: All wheat attack is not celiac

Currently, 1% of the United States population holds a diagnosis for celiac disease (CD), however, a more recently recognized and possibly related condition, "non-celiac gluten sensitivity" (NCGS) has been suggested to affect up to 6% of the United States public. While reliable clinical tests for CD exist, diagnosing individuals affected by NCGS is still complicated by the lack of reliable biomarkers and reliance upon a broad set of intestinal and extra intestinal symptoms possibly provoked by gluten. NCGS has been proposed to exhibit an innate immune response activated by gluten and several other wheat proteins. At present, an enormous food industry has developed to supply gluten-free products (GFP) with GFP sales in 2014 approaching $1 billion, with estimations projecting sales to reach $2 billion in the year 2020. The enormous demand for GFP also reflects a popular misconception among consumers that gluten avoidance is part of a healthy lifestyle choice. Features of NCGS and other gluten related disorders (e.g., irritable bowel syndrome) call for a review of current distinctive diagnostic criteria that distinguish each, and identification of biomarkers selective or specific for NCGS. The aim of this paper is to review our current understanding of NCGS, highlighting the remaining challenges and questions which may improve its diagnosis and treatment.

Lower Prevalence of Celiac Disease and Gluten-Related Disorders in Persons Living in Southern vs Northern Latitudes of the United States

BACKGROUND & AIMS

The association between prevalence of celiac disease and geographic region is incompletely understood, but the occurrence of several autoimmune disorders has been found to vary along a North-South gradient. We examined geographic, demographic, and clinical factors associated with prevalence of celiac disease and gluten-free diet in the United States.

METHODS

In a population-based study, we analyzed data on gluten-related conditions from the National Health and Nutrition Examination Survey, from 2009 through 2014, on 22,277 participants 6 years and older. We identified persons with celiac disease based on results of serum tests for IgA against tissue transglutaminase and endomysium or on both a health care provider diagnosis and adherence to a gluten-free diet. Gluten avoidance without celiac disease was defined as adherence to a gluten-free diet without a diagnosis of celiac disease. We compared mean serum levels of biochemical and nutritional markers based on status of gluten-related conditions.

RESULTS

We found 0.7% of participants to have celiac disease and 1.1% of participants to avoid gluten without celiac disease. Celiac disease was more common among individuals who lived at latitudes of 35°-39° North (odds ratio, 3.2; 95% confidence interval, 1.4-7.1) or at latitudes of 40° North or more (odds ratio, 5.4; 95% CI, 2.6-11.3) than individuals who lived at latitudes below 35° North, independent of race or ethnicity, socioeconomic status, and body mass index. Gluten avoidance without celiac disease was more common among individuals who lived at latitudes of 40° North or more, independent of demographic factors and body mass index. Participants with undiagnosed celiac disease (identified by positive results from serologic tests) had lower mean levels of vitamin B-12 and folate (data collected from 2009 through 2012) than persons without celiac disease. Participants with a health care provider diagnosis of celiac disease had a lower mean level of hemoglobin than persons without celiac disease. Mean levels of albumin, calcium, iron, ferritin, cholesterol, vitamin B-6, and vitamin D (data collected from 2009 through 2010) did not differ between participants with gluten-related conditions and those without.

CONCLUSIONS

In the US population, a higher proportion of persons living at latitudes of 35° North or greater have celiac disease or avoid gluten than persons living south of this latitude, independent of race or ethnicity, socioeconomic status, or body mass index. Mean levels of vitamin B-12 and folate are lower in individuals with undiagnosed celiac disease, and levels of hemoglobin are lower in participants with a diagnosis of celiac disease, compared with individuals without celiac disease.

Prevalence of Self-Reported Gluten Sensitivity and Adherence to a Gluten-Free Diet in Argentinian Adult Population

Background: Previous studies suggest that the prevalence of wheat/gluten sensitivity and adherence to a gluten-free diet (GFD) are high in Latin population despite a poor diagnosis of celiac disease. However, these prevalence rates still remain unknown in most Latin American countries. Methods: A cross-sectional survey study was conducted in Santa Fe, Argentina. Results: The estimated self-reported prevalence rates were (95% Confidence Interval [CI]): self-reported gluten sensitivity (SR-GS) 7.61% (6.2–9.2), SR-GS currently following a GFD 1.82% (1.2–2.7), celiac disease 0.58% (0.3–1.2), wheat allergy 0.33% (0.12–0.84), self-reported non-celiac gluten sensitivity (SR-NCGS) 6.28% (5.1–7.8), SR-NCGS currently following a GFD 0.91% (0.5–1.6), and adherence to a GFD 6.37% (5.1–7.9). SR-GS was more common in women (6.0%; p < 0.001) and associated with irritable bowel syndrome (p < 0.001). Among the GFD followers, 71.4% were doing it for reasons other than health-related benefits and 50.6% without medical/dietitian advice. In the non-SR-GS group, the main motivations for following a GFD were weight control and the perception that a GFD is healthier. Conclusion: In Argentina, gluten sensitivity is commonly reported and it seems that physicians/gastroenterologists are aware of celiac disease diagnosis. Trustable information about the benefits and potential consequences of following a GFD should be given to the general population.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: “food”, “diet”, “food allergy”, “food hypersensitivity”, “food intolerance”, “IBS”, “epidemiology”, “pathogenesis”, “pathophysiology”, “diagnosis”, “treatment”. We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

Diagnosis of gluten related disorders: Celiac disease, wheat allergy and non-celiac gluten sensitivity

Cereal crops and cereal consumption have had a vital role in Mankind’s history. In the recent years gluten ingestion has been linked with a range of clinical disorders. Gluten-related disorders have gradually emerged as an epidemiologically relevant phenomenon with an estimated global prevalence around 5%. Celiac disease, wheat allergy and non-celiac gluten sensitivity represent different gluten-related disorders. Similar clinical manifestations can be observed in these disorders, yet there are peculiar pathogenetic pathways involved in their development. Celiac disease and wheat allergy have been extensively studied, while non-celiac gluten sensitivity is a relatively novel clinical entity, believed to be closely related to other gastrointestinal functional syndromes. The diagnosis of celiac disease and wheat allergy is based on a combination of findings from the patient’s clinical history and specific tests, including serology and duodenal biopsies in case of celiac disease, or laboratory and functional assays for wheat allergy. On the other hand, non-celiac gluten sensitivity is still mainly a diagnosis of exclusion, in the absence of clear-cut diagnostic criteria. A multimodal pragmatic approach combining findings from the clinical history, symptoms, serological and histological tests is required in order to reach an accurate diagnosis. A thorough knowledge of the differences and overlap in clinical presentation among gluten-related disorders, and between them and other gastrointestinal disorders, will help clinicians in the process of differential diagnosis.

Grain and legume allergy

Among grains and legumes, wheat and soybean are the most frequent and well-characterized allergenic foods. Wheat proteins are divided into water/salt-soluble and water/salt-insoluble (gluten) fractions. The most dominant allergen in the former is α-amylase/trypsin inhibitor, which acts as an inhaled allergen causing baker's asthma. Gluten allergens, including ω-5 gliadin and high- and low-molecular-weight glutenins, contribute to wheat-dependent exercise-induced anaphylaxis in adults and immediate-type wheat allergies, including anaphylaxis, in children. Recently, wheat allergies exclusively caused by hydrolyzed wheat proteins or deamidated glutens have been reported, and the presence of unique IgE-binding epitopes has been suggested. Soybean allergens contributing to immediate-type allergic reactions in children are present in seed storage proteins, namely Gly m 5, Gly m 6 and Gly m 8. However, pollen-related soybean allergy in adults is caused by the Bet v 1 homolog of soybeans, Gly m 4. Taken together, the varying clinical manifestations of wheat and soybean allergies are predominantly caused by their different allergen components.

Food allergy: epidemiology and natural history

The prevalence of food allergy is rising for unclear reasons, with prevalence estimates in the developed world approaching 10%. Knowledge regarding the natural course of food allergies is important because it can aid the clinician in diagnosing food allergies and in determining when to consider evaluation for food allergy resolution. Many food allergies with onset in early childhood are outgrown later in childhood, although a minority of food allergy persists into adolescence and even adulthood. More research is needed to improve food allergy diagnosis, treatment, and prevention.

IgE-mediated food allergy in children

Food allergy is a serious health issue affecting roughly 4% of children, with a substantial effect on quality of life. Prognosis is good for the most frequent allergens with almost all children outgrowing their allergy. However, the long-term implications for disease burden are substantial for children with persistent allergies (eg, peanuts, tree nuts, fish, and shellfish) and for those with high concentrations of milk, egg, and wheat IgE. Antigen avoidance has been the time-honoured approach both for prevention and treatment. However, findings from studies done in the past 5 years show that early contact with food can induce tolerance and desensitisation to foods. We review the epidemiology, natural history, and management of food allergy, and discuss the areas of controversy and future directions in research and clinical practice.

Prevalence of wheat allergy in Al-Kharj, Saudi Arabia

BACKGROUND

Wheat allergy has been suggested to represent an important allergic disease. This study collates clinical and laboratory aspects in patients with wheat allergy in Al-Kharj city, Saudi Arabia.

METHODS

Total and specific IgE were measured in 15 suspected cases of wheat allergy. Protein allergenicity was assessed with Western blotting.

RESULTS

Significant elevation of total and specific IgE was found in 4 cases. Basophlia was also demonstrated on blood film. Western blotting results showed 2 bands (83 and 40 kDa).

CONCLUSION

Wheat allergy must also be considered when planning treatment of asthma and eczema of adult patients.

Prevalence of wheat allergy in Japanese adults

BACKGROUND

Wheat is one of the most common causes of food allergies. The exact prevalence of wheat allergy has not been well delineated in Japanese adults.

METHODS

We enrolled 935 adults in a cohort study established by Shimane University in order to examine the determinants of lifestyle-related diseases. A screening was conducted by a questionnaire-based examination and a detection of serum omega-5 gliadin-specific IgE. Subjects who tested positive in the questionnaire-based examination and/or the serum omega-5 gliadin-specific IgE test were further examined by detailed interviews and skin prick tests.

RESULTS

A total of 22 subjects were picked up by the screening process, and 17 of these were further examined by secondary testing. Only two subjects were conclusively identified as having wheat allergy.

CONCLUSIONS

The prevalence of wheat allergy in Japanese adults was found to be 0.21% by using a combination of questionnaire-based examination, skin prick test and serum omega-5 gliadin-specific IgE test.

Inhalable beta(1->3)glucans as a non-allergenic exposure factor in Dutch bakeries

OBJECTIVES

To obtain an overview of inhalable beta(1-->3)glucans levels in Dutch industrial bakeries and explore possible associations with reported respiratory health effects in bakery workers.

METHODS

beta(1-->3)glucan levels were analysed in 186 personal inhalable dust measurements obtained from a random population of bakery workers. Association between respiratory health effects and exposure to beta(1-->3)glucan was explored in a population of industrial bakery workers participating in a Health Surveillance System for flour processing sectors. Based on their job, bakery workers were assigned to low or high exposure categories given the average job exposure estimates obtained from the measurement study.

RESULTS

Bread bakers and dough makers had the highest exposures to beta(1-->3)glucans (GM 1.48 mug/m3 and 1.37 mug/m3 respectively). Strong correlations were found between airborne levels of inhalable dust and beta(1-->3)glucans, and between beta(1-->3)glucans and wheat allergens (Pearson correlation coefficients were 0.74 and 0.68 respectively). No significant associations could be identified between beta(1-->3)glucan exposure and work-related respiratory symptoms.

CONCLUSION

This study has shown that bakery workers are exposed to inhalable beta(1-->3)glucan levels comparable with exposure levels found in other occupational settings. More refined exposure assessment is necessary to fully understand the role of beta(1-->3)glucan exposure on respiratory health in bakery workers.

Prevalence of sensitization reported and objectively assessed food hypersensitivity amongst six-year-old children: a population-based study

There is a paucity of information on food hypersensitivity (FHS) in young children and there are even fewer population-based studies in this area. The aim of the study was to determine the prevalence of parentally reported FHS, and objectively diagnosed FHS amongst six-year-old children and to establish the rates of sensitization to key allergens. This population-based cohort study recruited 798 6-year-olds resident on the Isle of Wight (UK). Sensitization rates, reported rates of FHS and objectively assessed FHS was established using food challenges. A total of 94 (11.8%) 6 yr olds reported a problem with a food or food ingredient. The rate of sensitization to the pre-defined panel of food allergens was 25/700 (3.6%). Based on open food challenge and/or suggestive history and skin tests, the prevalence of FHS was 2.5% (95% CI 1.5-3.8). Based on double-blind challenges, a clinical diagnosis or suggestive history and positive skin tests, the prevalence was 1.6% (95% CI 0.9-2.7). The rates of perception of FHS are higher than the prevalence of sensitization to main food allergens and the prevalence of FHS based on food challenges. Milk, peanut and wheat were the key food allergens amongst those with positive challenges.

[Allergyto alpha-amylase in apprentice bakers--prevalence, incidence, risk factors and clinical symptoms]

BACKGROUND

The aim of the study was to evaluate the prevalence, incidence and risk factors of hypersensitivity to alpha-amylase as well as to identify allergy-related clinical symptoms in apprentice bakers.

MATERIALS AND METHODS

A group of 287 apprentice bakers was examined by using a questionnaire, performing skin prick tests to common and occupational allergens, and evaluating total serum IgE level, specific anti-flour and alpha-amylase IgE before, 1 year and 2 years after the onset of vocational training. To diagnose occupational respiratory disease, spirometry, histamine and allergen specific inhalation challenge tests were performed.

RESULTS

None of the apprentices displayed the presence of alpha-amylase-specific IgE before starting vocational training. After the first year of occupational exposure, one subject developed hypersensitivity to alpha-amylase, and other 27 subjects after the second year. Generally, 28 (9.8%) apprentices showed hypersensitivity to alpha-amylase after two years of occupational exposure. Of those subjects, 17 (60.7%) had occupational allergic rhinitis recognized and 15 (53.6%) occupational asthma. Logistic regression analysis revealed that the positive results of SPT to common allergens and moulds are significant risk factor for the development of hypersensitivity to alpha-amylase (OR = 11.98, 95% CI: 2.60-55.08 and OR = 7.45, 95% CI: 1.12-49.61, respectively).

CONCLUSION

The incidence of allergy to alpha-amylase increases with increasing duration of exposure. Hypersensitivity to common allergens, especially to moulds, is a risk factor of occupational allergy to alpha-amylase. The study results confirm that skin prick tests to common allergens, particularly to moulds, should be performed in bakers before starting occupational exposure and subjects with positive results should be considered as a group of high risk of occupational allergy.

Evaluation of the prevalence of antiwheat-, anti-flour dust, and anti-alpha-amylase specific IgE antibodies in US blood donors

BACKGROUND

Asthma in bakery workers is one of the most frequently occurring forms of occupational asthma in the world. Experience from other countries has shown the prevalence of sensitization (IgE) to bakery-associated allergens (BAAs) (wheat [W], flour dust [FD], alpha-amylase [AA]) in bakery workers to be 5% to 53%, whereas the prevalence in nonoccupationally exposed individuals was estimated to be 1.2% to 6.4%.

OBJECTIVE

To estimate the prevalence of BAA sensitization by measuring BAA specific IgE in the residual serum tubes of volunteer blood donors.

METHODS

Serum samples from 534 volunteer blood donors were measured for anti-W, anti-FD, and anti-AA specific IgE antibodies (in duplicate) using the AlaSTAT microplate assay. Samples with BAA IgE concentrations of 0.35 kU/L or greater were considered positive.

RESULTS

Nineteen of 530 serum samples (3.6%; 95% confidence interval [CI], 3.3%-3.9%) were positive for W (range, 0.38-3.61 kU/L), whereas 31 of 534 (5.8%; 95% CI, 5.3%-6.3%) were positive for FD (range, 0.35-2.34 kU/L) and 5 of 529 (1.0%; 95% CI, 0.9%-1.1%) were positive for AA (range, 0.38-1.59 kU/L). Thirteen serum samples were positive for both W and FD; 1 sample each was positive for W and AA and FD and AA.

CONCLUSIONS

The prevalence of IgE sensitization in serum samples from a relatively large unselected population of volunteer blood donors is 1.0% for AA, 3.6% for W, and 5.8% for FD, which agrees well with data from other countries for sensitization prevalence rates for nonoccupationally exposed individuals.