Rosalie Karen Woods

International prevalences of reported food allergies and intolerances. Comparisons arising from the European Community Respiratory Health Survey (ECRHS) 1991-1994

Objective: The aim of this study was to report the prevalence, type and reported symptoms associated with food intolerance.Design: A cross-sectional epidemiological study involving 15 countries using standardized methodology. Participants answered a detailed interviewer-administered questionnaire and took part in blood, lung function and skin prick tests to common aeroallergens.Setting: Randomly selected adults who took part in the second phase of the European Community Respiratory Health Survey (ECRHS).Subjects: The subjects were 17280 adults aged 20–44 y.Results: Twelve percent of respondents reported food allergy/intolerance (range 4.6% in Spain to 19.1% in Australia). Atopic females who had wheezed in the past 12 months, ever had asthma or were currently taking oral asthma medications were significantly more likely to report food allergy/intolerance. Participants from Scandinavia or Germany were significantly more likely than those from Spain to report food allergy/intolerance. Respondents who reported breathlessness as a food-related symptom were more likely to have wheezed in the past 12 months, to have asthma, use oral asthma medications, be atopic, have bronchial hyperreactivity, be older and reside in Scandinavia.Conclusion: Self-reported food allergy/intolerance differed significantly across multiple countries. The reasons for these differences were not explored in this study, but are likely to be largely due to cultural differences.Sponsorship: Rosalie Woods holds a postdoctoral research fellowship from the National Health and Medical Research Council of Australia (no. 9797/0883).European Journal of Clinical Nutrition (2001) 55, 298–304

Reported adverse food reactions overestimate true food allergy in the community

Objective: To determine the extent to which perceived adverse food reactions were associated with IgE mediated food allergy, as defined by skin prick testing (SPT).Design: A cohort epidemiological study. Participants underwent SPT to five common food allergens (cows milk, peanut mix, egg white, shrimp and whole grain wheat mix) and were asked whether they had ever suffered any food ‘illness/trouble’, and if so to list such food(s). A positive SPT was defined as wheal diameter of ≥3 mm. Cohens kappa (κ) was used to assess the agreement between SPT and self-reported reactions to food(s) which contained the allergen of interest.Setting: Randomly selected adults who took part in the follow-up of the European Community Respiratory Health Survey (ECRHS) in 1998.Subjects: The subjects were 457 adults aged 26–50 y.Results: Fifty-eight (13%) adults were sensitised to at least one food allergen whilst 99 adults (22%) reported illness to food(s) nearly always. However, only seven subjects who reported illness to a food also had a positive SPT to the same food. The prevalence of adverse food reactions associated with IgE mediated allergy in the adult general population would be less than 1.5% (7/457). The agreement between SPT and self-reported illness to food(s) was poor for cows milk (κ=0) and wheat (κ=0), slight for shrimp (κ=0.16) and egg white (κ=0.09) and fair for peanut mix (κ=0.37).Conclusions: There was little agreement between self-reported perceived illness to food(s) known to contain the food allergen of interest, and positive SPT, suggesting that most reactions are not due to IgE mediated food allergy.Sponsorship: The National Health and Medical Research Council of Australia (NH&MRC) funded this study. Rosalie Woods holds a postdoctoral research fellowship from the NH&MRC (#9797/0883).

Prevalence of food allergies in young adults and their relationship to asthma, nasal allergies, and eczema

BACKGROUND The true prevalence of food allergy in adults is generally thought to be uncommon. It is unknown whether there are any relationships between food allergy and atopic diseases. OBJECTIVE To determine the prevalence of probable immunoglobulin (Ig)E-mediated food allergy to peanut, shrimp, cows milk, wheat, and egg as defined by a positive skin prick test result and relevant clinical history to the same food, and to explore the relationship with atopic diseases. METHODS Cross-sectional epidemiologic study. One thousand one hundred forty-one randomly selected young adults (aged 20 to 45 years) underwent skin prick testing to five common food allergens (cows milk, peanut, egg white, shrimp, and wheat), completed a detailed questionnaire, including validated items on respiratory symptoms, history of asthma and other allergic conditions, as well as undergoing lung function testing. RESULTS Just over one percent (1.3%, n = 15) had probable IgE-mediated food allergy. The prevalence of probable IgE food allergy was: <0.27% for wheat, 0.09% (95% confidence interval = 0.0 to 0.49%) each for cows milk and egg, 0.53% (0.21 to 1.09%) for shrimp, and 0.61% (0.25 to 1.26%) for peanut. Those with probable IgE peanut and shrimp allergy were significantly more likely to have current asthma and doctor-diagnosed asthma. Wheeze and history of eczema were also associated with peanut allergy, whereas nasal allergies were associated with shrimp allergy. CONCLUSIONS The prevalence of probable IgE-mediated food reactions is rare in young adults. Some positive associations between probable IgE-mediated food allergy and allergic diseases were found, but larger study numbers are required to confirm these results.

Maternal breast milk long‐chain n‐3 fatty acids are associated with increased risk of atopy in breastfed infants

Background Australia has one of the highest prevalence rates internationally of allergic conditions, such as asthma and eczema. Atopy is one hallmark for the development of allergic disease and predisposes to allergic inflammation in the target organs. ω‐3 (n‐3) fatty acids (FAs) are thought to act as precursors to the formation of less active inflammatory mediators, with the potential to reduce inflammation.

Fatty acid levels and risk of asthma in young adults

Background: There is current interest in the possible protective effect of long chain (n-3) fatty acids from fish in chronic lung diseases such as asthma. The aim of this community based cross sectional study was to determine whether plasma long chain (n-3) fatty acids, as a measure of dietary intake, differed between 1601 young adults with and without asthma. Methods: Subjects of mean (SD) age 34.6 (7.1) years completed a detailed respiratory questionnaire, food frequency questionnaire, skin prick testing, and lung function tests including methacholine challenge test for bronchial hyperreactivity (BHR) and had venous blood taken for analysis of plasma fatty acids. Plasma fatty acid levels (%) were analysed using multiple logistic regression with alternative definitions of asthma and atopy as the outcomes. Results: Atopy was not associated with any plasma fatty acid. The n-3 polyunsaturated fatty acids and n-6:n-3 ratio were not consistently associated with asthma or atopy. The n-6 polyunsaturated fatty acid dihomo γ-linolenic acid (DHGLA) was positively associated with current asthma (OR = 1.30, 95% CI 1.06 to 1.60), asthma (OR = 1.34, 95% CI 1.13 to 1.60), and doctor diagnosed asthma (OR = 1.25, 95% CI 1.06 to 1.48). Conclusion: Plasma n-3 fatty acids are not associated with a reduced risk of asthma or atopy among young adults. The association of DHGLA with asthma warrants further research to determine a cause-effect relationship.

The effects of monosodium glutamate in adults with asthma who perceive themselves to be monosodium glutamate–intolerant ☆ ☆☆ ★ ★★

BACKGROUND Many previous clinical studies of food-induced asthma suffer from inadequate baseline or control data. A statistically valid, randomized, double-blind, placebo-controlled, monosodium glutamate (MSG)-challenge protocol was developed for identifying early and late asthmatic reactions in an individual. OBJECTIVE We sought to determine whether MSG would induce bronchoconstriction in a group of adults with asthma who perceived that they were MSG sensitive. METHODS Twelve subjects (seven women, mean age 35.3 years) with clinically documented asthma and a perception of MSG-induced asthma were recruited. FEV1 and peak expiratory flow data were obtained for 3 whole control days, as well as time-matched data for 3 separate challenge days (1 gm MSG, 5 gm MSG, and 5 gm lactose [placebo]). Opaque capsule challenges were given as a single dose in the morning after an overnight fast. Subjects complied with an elimination diet throughout the study. Nonspecific bronchial hyperresponsiveness was measured at baseline, after the control days, and at the conclusion of the challenges. Venous blood samples were taken at baseline and on each challenge day to determine soluble inflammatory marker (eosinophil cationic protein and tryptase) activity. RESULTS No immediate or definite late asthmatic reactions occurred. One subjects FEV1 declined more than 15% on MSG challenge, but 95% confidence limits for the control-day spirometry showed that this decline was within her daily variation, hence the challenge was deemed to be negative. No significant changes in bronchial hyperresponsiveness or soluble inflammatory markers were found. CONCLUSIONS MSG-induced asthma was not demonstrated in this study. This study highlighted the importance of adequate baseline and control data and indicated that such a rigorous protocol for individual assessment is feasible.

Do dairy products induce bronchoconstriction in adults with asthma

BACKGROUND Dairy products have often been implicated as a cause of exacerbation of asthma, but there is little scientific evidence to support this hypothesis. OBJECTIVE We sought to determine whether dairy products induce bronchoconstriction in a group of adults with asthma. METHODS Twenty subjects with asthma (13 women and 7 men) were recruited from respondents who had previously completed a food and asthma questionnaire. Ten subjects perceived that their asthma became worse with ingestion of dairy products (positive perceivers), whereas ten were negative perceivers. None of the subjects had positive skin prick test results with cows milk. The study was a randomized, cross-over, double-blind, placebo-controlled trial. Subjects complied with a dairy-free diet throughout the study. The active challenge was a single-dose drink equivalent to 300 ml of cows milk. A positive reaction was defined as a 15% reduction in both FEV1 and peak expiratory flow (PEF) on the active challenge day compared with results obtained at the same time on the placebo day. RESULTS For both FEV1 and PEF there were no statistically significantly differences in group means between active challenge and placebo challenge, between sequence of administration, or between perceptions. Nine subjects showed FEV1 or PEF changes that were greater than 15% of baseline values: four patients showed changes after both active and placebo treatment; two after treatment with placebo only; and three after active treatment alone. Of the latter group, two subjects showed changes only in PEF, and when one of these subjects underwent a further detailed study, no asthmatic reaction could be demonstrated. CONCLUSION It is unlikely that dairy products have a specific bronchoconstrictor effect in most patients with asthma, regardless of their perception.

The rising prevalence of asthma in young Melbourne adults is associated with improvement in treatment

BACKGROUND Asthma is a common source of morbidity and is now recognized as a national health priority in Australia. Although a number of epidemiologic studies have been conducted in Australia to determine the prevalence of asthma in adults, it is unclear whether the prevalence is changing. OBJECTIVES To determine the prevalence in 1998 of self-reported asthma and respiratory symptoms among young adults and changes in prevalence between 1990 and 1999. METHODS Cross-sectional postal survey to 4,455 young adults (aged 20 to 44 years) randomly selected from the electoral rolls of the inner southeastern suburbs of metropolitan Melbourne. The survey instrument was the validated European Community Respiratory Health Survey screening questionnaire, which gathered data on self-reported respiratory symptoms, including whether asthma had been diagnosed. Identically worded questions from similar surveys conducted in 1990, 1992, and 1999 were used to compare changes in prevalence. RESULTS A response rate of 72% was achieved in 1998 after three mailings and telephone followup. Forty-two percent reported nasal allergies, 26% wheezed within the past 12 months, and 20% ever had asthma. The prevalence of doctor-diagnosed asthma was 18%, whereas 10% reported using asthma medications within the past 12 months. Nine percent of respondents reported an asthma attack within the past 12 months. The prevalence of having ever had asthma, doctor-diagnosed asthma, and using asthma medications had increased significantly since 1990. However, the prevalence of respiratory symptoms did not significantly change over this time. CONCLUSIONS The prevalence of asthma is likely to be rising, but the symptoms of asthma are being better managed in young Melbourne adults.

Wheeze not current asthma affects quality of life in young adults with asthma

Background: A study was undertaken to investigate quality of life in asthma, defined by differing criteria, to see which may be most appropriate in epidemiological studies. Methods: The 426 adults were participants in the follow up phase of the European Community Respiratory Health Survey (ECRHS) in Melbourne. As part of the laboratory visit, participants completed the SF-36 quality of life questionnaire, a detailed respiratory questionnaire, and underwent lung function testing. Results: Both the physical component summary and the mental component summary scores were significantly worse in those with wheeze in the previous 12 months than in those without wheeze. Only the mental component summary score was significantly worse in those with current asthma than in those without. In contrast, in those with current asthma or bronchial hyperreactivity only, neither of the summary scales was significantly different between cases and controls. Conclusions: Quality of life is severely impaired in individuals with wheeze in the previous 12 months while individuals with current asthma or bronchial hyperreactivity alone did not appear to have significantly reduced quality of life.

Reported food intolerance and respiratory symptoms in young adults.

The aim of the study was to assess the ability of the European Community Respiratory Health Survey (ECRHS) questionnaire to provide data on the prevalence, type and reported symptoms associated with food intolerance from a group of young adults in Melbourne. Six hundred and sixty nine randomly selected subjects completed the questionnaire with 553 attending the laboratory for skin-prick tests, anthropometry, and ventilatory function tests. A further 207 symptomatic participants completed the questionnaire, with 204 of them attending the laboratory. Seventeen per cent of all respondents reported food intolerance or food allergy. A wide variety of food items was cited as being responsible for food-related illnesses. Those with current asthma did not report food-related illness more frequently than those without asthma. Respondents who reported respiratory symptoms following food ingestion were more likely to be atopic, to have used inhaled respiratory medications in the previous 12 months, reported less exposure to regular passive smoking over the past 12 months and weighed more. These associations between respiratory symptoms and food intolerance require further prospective investigation and verification. The importance of using appropriate dietary methodology in future studies for determining diet-disease relationships was highlighted by this study.