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PubMedDate not supplied

[Frequency of exercise-induced asthma in a group of children and adolescents with mild asthma attending a summer camp].

BACKGROUND: Exercise-induced asthma is a transitory bronchospasm, which occurs after 6 to 8 minutes of continuous exercise. Diagnosis is done by a suggestive clinical history and by 15 to 20% post-challenge fall in FEV1. It happens in about 6 to 13% of general population, 90% of asthmatic individuals and 40% of individuals with allergic rhinitis. OBJECTIVE: To know the frequency of asthma induced by exercise in a group of asthmatic children and teenagers who went to a summer camp. MATERIAL AND METHODS: A cross-sectional, descriptive and observational study, which included 33 patients suffering from intermittent mild asthma, was based on espirometric measurements made before and after 8 minutes of continuous exercise (running). None of them had previous diagnosis of exercise-induced asthma. FEV1 greater than or equal to 15% was considered exercise-induced asthma. The test was performed at a room temperature of 73F and humidity of 40%. All patients were asymptomatic before the study and were given short-acting inhaled beta2-agonists as rescue medication, which was not administered during the 12 previous hours to the test. Data analysis was made by means of descriptive statistic. RESULTS: Thirty-three children aged 8-16 years with diagnosis of asthma were studied, with an average age of 12.5 years; 42.4% were female and 57.5% male. Of the 33 patients, 6 had (18.2%) a 15% fall in FEV1 after exercise; 50% of these patients showed exercise-induced mild asthma, 33% moderate and 17% severe. At the end of the test, in six patients (100%) FEV1 increased by 15%, five minutes after the administration of a beta2-agonist. CONCLUSIONS: Exercise-induced asthma is frequent among asthmatic pediatric patients, occurring in 18.8% of this study. Likelihood of having exercise-induced asthma must be deliberately investigated in all asthmatic patients, in order to establish an opportune diagnosis of this condition and provide recommendations of preventing therapy.

Adolescent↗
PubMed2006

[Characteristics of mild asthma: descriptive epidemiology and nature of bronchial inflammation. Position of the Mild Asthma Working Group].

INTRODUCTION: Update on the state of knowledge in the mild asthma (intermittent and persistent mild asthma, according to the GINA classification) literature, and position of a French Mild Asthma Working Group. STATE OF THE ART: The French Mild Asthma Working Group (11 lung specialists, 4 paediatricians, 1 pharmacologist, and 1 general practitioner) selected, analysed, and summarised the literature on the epidemiology, physiopathology, clinical signs, and management of mild asthma. The present article shows the position of the working group on mild asthma descriptive epidemiology (causal factors excluded) and the nature of the bronchial inflammation. Clinical signs and medicinal treatments will be presented in a second article. PERSPECTIVES: Between 50% and 75% of asthma patients, depending on the study, present mild asthma. Childhood-to-adulthood cohort monitoring found severity to be unchanged over developmental time. Its generally benign evolution may in some (<10%) cases be complicated by severe episodes. Inflammation and airway-wall remodelling were always found, although of variable intensity, and non-specific (except for absence of infiltration by polymorphonuclear neutrophils). Corticosteroid therapy by inhalation reduces bronchial inflammation, but with little impact on airway-wall remodelling. CONCLUSION: The present findings should help clinicians in identifying and understanding mild asthma.

Adrenal Cortex Hormones↗
PubMed2006

Effectiveness of nebulizer use-targeted asthma education on underserved children with asthma.

OBJECTIVE: To determine the effectiveness of a home-based asthma education intervention in increasing appropriate nebulizer use and reducing symptom frequency, emergency department (ED) visits, and hospitalizations over 12 months. DESIGN: A randomized clinical trial. Settings Pediatric primary care, pulmonary/allergy, and ED practices associated with the University of Maryland Medical System and The Johns Hopkins Hospital, Baltimore. PARTICIPANTS: Children with persistent asthma, aged 2 to 9 years, with regular nebulizer use and an ED visit or hospitalization within the past 12 months. Children were randomized into the intervention (n = 110) or control (n = 111) group. Follow-up data were available for 95 intervention and 86 control children. INTERVENTION: Home-based asthma education, including symptom recognition, home treatment of acute symptoms, appropriate asthma medication, and nebulizer practice. MAIN OUTCOME MEASURES: Estimates of mean differences in asthma symptom frequency, number of ED visits and hospitalizations and appropriate quick relief, controller medication, and nebulizer practice over 12 months. RESULTS: Of the 221 children, 181 (81.9%) completed the study. There were no significant differences in home nebulizer practice, asthma morbidity, ED visits, or hospitalizations between groups (P range, .11-.79). Although most children received appropriate nonurgent asthma care (mean, 2 visits per 6 months), more than one third of all children received at least 6 quick-relief medication prescriptions during 12 months, with no difference by group. CONCLUSIONS: A nebulizer education intervention had no effect on asthma severity or health care use. Of concern is the high quick-relief and low controller medication use in young children with asthma seen nearly every 3 months for nonurgent care.

Asthma↗
PubMed1998

Relation between occupational asthma case history, bronchial methacholine challenge, and specific challenge test in patients with suspected occupational asthma.

Inhalative methacholine challenge (MC) was performed in 229 subjects presumed to suffer from occupational asthma due to exposure to airborne latex allergens (n = 62), flour (n = 28), isocyanates (n = 114), or irritants in hairdressers' salons (n = 25). They were also subjected to specific challenges with the occupational agents they were exposed to, completed a questionnaire using an abbreviated version of the ATS-DLD, and were interviewed by an experienced physician. Bronchial hyperresponsiveness in MC was defined by the results obtained in a previous study with 81 healthy volunteers. The threshold in these controls was set at a cumulative MC dose of 0.3 mg, corresponding to a sensitivity of 95%. The main purpose of the study was to investigate whether the MC and/or the occupational asthma case history are reliable predictors of the specific challenge test outcomes. In 40-72% of examined subjects, workplace-related asthma complaints occurred, with bronchial hyperreactivity in the MC ranging from 48% to 61%. However, only 12-25% demonstrated a significant bronchoconstructive reaction in the specific challenge test. MC results are only moderately associated with workplace-related asthma case histories. Positive outcomes of challenges with occupational agents are well correlated with positive MC results plus occupational asthma case histories. The combination of MC and occupational asthma case history shows a relatively high specificity (62%, 86%, 80%), but the sensitivity was moderately low (83%, 71%, 52%). MC sensitivities were 92%, 71%, and 62% (case histories of hairdressers were not available). We conclude that in most cases, occupational asthma (as defined by a specific challenge test response) is combined with bronchial hyperresponsiveness and workplace-related asthmatic symptoms. However, subjects of each exposure group demonstrated bronchial hyperresponsiveness and complained of workplace-related asthmatic symptoms, but occupational asthma could not be proved in the specific challenge test. In subjects with a positive occupational asthma case history, a negative MC test result can almost rule out a positive specific challenges test result. Hence, the MC test can reduce performance of the laborious specific challenge test.

Adult↗
PubMed2002

Prevalence of asthma and asthma-like symptoms in inner-city elementary schoolchildren.

American inner-city children are disproportionately affected by asthma. During the 1999-2000 school year, we conducted a survey of 6 Bronx, New York City elementary schools to assess the prevalence of asthma and asthma-like symptoms as reported by parents. Children with probable asthma had symptoms within the last 12 months and parents who indicated that their child had asthma. Children with possible asthma had symptoms within the last 12 months but lacked a diagnosis.Overall, 74% (4,775/6,433) of parents returned completed surveys, identifying 20% (949/4,775) of children as probable asthmatics, and 12% (589/4,775) as possible asthmatics. In multivariate analyses, probable asthma was associated with: Puerto Rican, Black, and white race/ethnicity, male gender, having health insurance, and registration at the poorest school. Possible asthma was associated with lack of health insurance and female gender, but was not associated with any specific race/ethnicity. Our findings support the effectiveness of school-based surveys to identify children at high risk for asthma. The challenge remains to engage children and families in appropriate follow-up care and to manage their illness, either through the use of school-based health centers or stronger links to community services.

Age Factors↗
PubMed1988

Allergy in asthma. I. The dose relationship of allergy to severity of childhood asthma.

The relationship between allergy and childhood asthma was investigated. We hypothesized that if allergy were a factor in aggravating asthma, we should find that allergy (defined by symptoms and numbers of positive prick skin tests) increased with increasing severity of asthma. One hundred forty-two children with asthma, referred to a pulmonologist and an allergist, 123 of whom were skin tested, were graded according to clinical severity and compared to a group of 29 normal individuals, 48 patients with allergic rhinitis, and 52 patients with cystic fibrosis. The 29 symptom-free individuals had only one positive skin test among them, whereas 65% of the clinic patients with asthma had three or more positive skin tests (p less than 0.001). This compared with 35.4% of the patients with rhinitis (p less than 0.001) and 14% of the patients with cystic fibrosis (p less than 0.001). There was an increase in the number and size of positive skin tests with increasing severity of asthma. Similarly, there was increased reporting of allergic symptoms, such as sensitivity to animals with increasing severity of asthma. These data indicate that atopy is associated with asthma in a crude dose-response fashion, and children with chronic, steroid-dependent asthma are often highly atopic, easily sensitized, and form IgE antibodies to a broad range of allergens.

Adolescent↗
PubMed1995

Prevalence of asthma and asthma-like symptoms in three French cities.

BACKGROUND: This study is part of the European Community Respiratory Health Survey (ECRHS), which uses a common methodology in different areas throughout the world. This paper describes the prevalences of reported asthma, asthma-like symptoms and nasal allergies, their relationships to age group and sex, and the relationships of asthma-like symptoms to current asthma, in the general population aged 20-44 years of three French urban areas. METHODS: The study population of 2804 subjects in Grenoble, 3774 in Montpellier and 3152 in Paris (18th district), randomly selected from electoral rolls, answered a postal questionnaire (stage I of ECRHS). The response rates were 77.8%, 68.6% and 74.4%, respectively. RESULTS: The prevalences were approximately 14% for wheezing, 16% for chest tightness and 4.5% for nocturnal shortness of breath in the three areas. Asthma attacks in the last 12 months were reported by 2.7% of subjects in Grenoble, 3.5% of subjects in Montpellier and 4.0% of subjects in Paris (P = 0.02). For nasal allergies, the prevalences were 28.0%, 34.3% and 30.8%, respectively (P < 0.001). Asthma was inversely correlated to age (higher prevalence in the youngest) but was not related to sex. Neither age distribution nor sex ratio explained the differences between areas. Among the asthma-like symptoms, wheezing and nocturnal shortness of breath correlated strongly with asthma, chest tightness correlated moderately and nocturnal coughing correlated poorly. CONCLUSION: The prevalences observed were higher than expected from previous comparable French studies in young adults. These results are consistent with the hypothesis of a recent increase of asthma and allergies.

Adult↗
PubMed2006

The economic impact of children dispensed asthma medications without an asthma diagnosis.

OBJECTIVE: To compare the resource utilization and healthcare costs of children with a diagnosis of asthma, children dispensed asthma medications but without a diagnosis of asthma, and control children. STUDY DESIGN: Children 0 to 17 years old were identified from an integrated managed-care database during calendar year 2001. They were compared on the basis of the presence of a medical claim for asthma (Dx cohort); a prescription for an asthma controller or reliever medication (excluding oral corticosteroids) but without an asthma diagnosis (Rx cohort), and control children. Using medical and pharmacy claims, resource utilization and costs were compared across cohorts. RESULTS: Children in both the Dx and Rx cohorts had significantly greater nonasthma and total all-cause annual healthcare costs compared with control children. The Dx and Rx cohorts had higher rates of nonasthma emergency department visits and hospitalizations. The risk of an oral corticosteroid dispensed was 14-fold and 7-fold greater for the Dx and Rx cohorts, respectively, compared with the control children. These findings were consistent in infant, toddler, school-age, and adolescent groups. CONCLUSIONS: Children dispensed asthma medications but lacking an asthma diagnosis have considerable morbidity and incur high healthcare resource utilization. This study suggests that better recognition of pediatric asthma is warranted.

Adolescent↗
PubMed1999

Exposure and sensitization to cat dander: asthma and asthma-like symptoms among adults.

BACKGROUND: Several pets, such as cats, dogs, and rodents, are known to produce allergens. Despite the clinical and laboratory evidence that exposure to pets can cause bronchoconstriction in sensitized subjects, the results of population studies have been contradictory. OBJECTIVES: The purpose of this study was to investigate the relationship between cat ownership and the prevalence of asthma, asthma-like symptoms, and bronchitic symptoms among subjects 20 to 44 years of age in Vancouver, Canada and to determine whether sensitization is responsible for such an association. METHODS: Two thousand nine hundred ninety-nine (88%) randomly selected subjects responded to a mail questionnaire. Of these, 504 participated in laboratory examination, including allergy skin testing. RESULTS: One thousand nineteen study responders (34%) were pet owners at the time of the study (current owners). Current pet owners were found to have a higher prevalence of current asthma, asthma-like symptoms, and bronchitic symptoms compared with those without pets. Cat owners had significantly higher risk of having current asthma and asthma-like symptoms. In the subset who had allergic skin tests, we found that those who were allergic to cat dander had a significantly higher risk of current asthma than those not allergic to cat dander and not owning a cat. CONCLUSION: This study provides evidence that sensitization to cat dander is a more important risk factor for current asthma and asthma-like symptoms than cat ownership itself.

Adult↗
PubMed2000

Effect of suplatast tosilate, a Th2 cytokine inhibitor, on steroid-dependent asthma: a double-blind randomised study. Tokyo Joshi-Idai Asthma Research Group.

BACKGROUND: Th2 cytokines play an important part in the pathogenesis of asthma. Our aim was to study the effect of suplatast tosilate, a selective Th2 cytokine inhibitor, on asthma control and asthma exacerbations during reduction of inhaled corticosteroid dose in patients with steroid-dependent asthma. METHODS: 85 patients with moderate to severe asthma taking high doses (> or = 1500 microg per day) of inhaled beclometasone dipropionate, were assigned suplatast tosilate (100 mg three times daily) or placebo for 8 weeks in a double-blind, randomised, parallel-group, multicentre trial. During the first 4 weeks, other medications remained unchanged (add-on phase); during the next 4 weeks, the doses of beclometasone were halved (steroid-reduction phase). Main outcome measures were pulmonary function, asthma symptoms, and use of beta2-agonists. FINDINGS: Data were available from 77 patients. During the add-on phase, suplatast tosilate treatment, compared with placebo, was associated with higher forced expiratory volume in 1 s (mean difference between groups for changes from baseline at week 4, 0.20 L [95% CI 0.16-0.24], p=0.043), morning peak expiratory flow (18.6 L/min [14.1-23.1], p=0.037), and less diurnal variation in peak expiratory flow rate, asthma symptom scores (7.1 [6.6-7.6], p=0.029), and serum concentrations of eosinophil cationic protein and IgE. In the steroid-reduction phase, pulmonary function, asthma symptoms, and use of beta2-agonist deteriorated significantly more in the placebo group than in the suplatast group. INTERPRETATION: Treatment with a Th2 cytokine inhibitor in steroid-dependent asthma improves pulmonary function and symptom control, and allows a decrease in dose of inhaled corticosteroid without significant side-effects. Some improvements in pharmacokinetics are, however, needed.

Administration, Inhalation↗
PubMed1997

[Clinical characteristics and morbidity in stable asthma. A descriptive analysis of asthma in a Mediterranean community].

UNLABELLED: Scarce clinical and epidemiological data related to asthma are available in Spain. OBJECTIVES: a) to determine the severity of disease and morbidity among symptomatic asthmatics, and b) to determine whether international recommendations for the treatment of asthma are being followed. A prospective descriptive study enrolling asthmatics older than 14 years of age who experienced symptoms within the past year. The study was performed in the Osona district, a semi-rural area north of Barcelona. Spirometric tests were given and case histories taken, including symptoms caused by the disease. The international guidelines analyzed were those published in 1992 by the National Institutes of Health for the International Consensus Report on Diagnosis and Treatment of Asthma. We studied 333 patients; 214 (64%) were women and 119 (36%) men. Asthma was mild in 140 (42%), moderate in 116 (35%) and severe in 77 (23%). The need for short-term oral corticosteroids, visits to primary care physicians, and missed work days were all significantly greater among patients with severe asthma than for those with mild or moderate asthma. However, 23% of the patients with mild asthma missed work at least once. Drugs used were beta-adrenergic agonists of short duration of effect (76%) and inhaled corticosteroids (66%). CONCLUSIONS: a) in most symptomatic asthma patients, disease is mild; b) although patients with severe asthma have higher rates or morbidity, patients with mild disease also have marked symptoms; c) the drugs used for treatment are in compliance with the 1992 international guidelines.

Adolescent↗
PubMedDate not supplied

[Satellite symposium: Asthma in the World. Asthma among children in Latin America].

The prevalence of respiratory symptoms related to asthma in children from Latin America has been largely ignored. This region participated in phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC) with 17 participating centers in phase I and 78 centers in phase III. Data were obtained on asthma, rhinitis and eczema from countries and centers with markedly different climactic, cultural and environmental conditions and socioeconomic development. The results for phase I are presented herein because data from phase III are currently being revised at the ISAAC international data control center and will be officially available in the second half of 2004. Phase I provided important information on the prevalence of asthma in the participating countries and demonstrated wide variation among centers in the same country and among countries. The participating Latin American countries are all developing countries and share more or less the same problems related to low socioeconomic status. Therefore, the results and figures should be analyzed within that context. The range for accumulative and current asthma symptoms in children from the Latin American countries that participated in phase I (89,000) were as follows: the prevalence of asthma ranged from 5.5% to 28% in children aged 13-14 years and from 4.1% to 26.9% in children aged 6-7 years. The prevalence of wheezing in the previous 12 months ranged from 6.6% to 27% in children aged 13-14 years and from 8.6% to 32.1% in children aged 6-7 years. The high figures for asthma in a region with a high level of gastrointestinal parasites infestation, a high burden of acute respiratory and gastrointestinal infections occurring early in life, severe environmental and hygiene problems, suggest that these factors, considered as protective in other (developed) regions of the world, do not have the same effect in this region. Furthermore, those aggressive environmental conditions acting together from very early in life might condition different asthmatic phenotypes with more severe clinical presentation in infancy (first 2 years of life), lower atopy and enhanced airways reactivity. The present study indicates that the prevalence of asthma and related symptoms in Latin America is as high and variable as described previously for industrialized or developed regions of the world and that the environmental risk factors, mainly related with poverty, could be responsible for the different clinical and functional presentations of asthma in children from developing regions.

Adolescent↗
PubMed1997

Are high generalised and asthma-specific self-efficacy predictive of adequate self-management behaviour among adult asthma patients?

In asthma self-management training, often self-treatment guidelines are included, because increased knowledge of asthma alone is not sufficient to change behaviour. One way to achieve behavioural changes is by increasing the patient's general and asthma-specific self-efficacy expectancies. This refers to beliefs in one's capabilities to execute the recommended course of action successfully. We wanted to assess whether high generalised and asthma-specific self-efficacy expectancies were predictive of adequate self-management and self-treatment behaviour. A questionnaire was sent to 4563 persons (18-65 years) who had used inhaled medication in 1993. Self-management and self-treatment behaviour were operationalised through a hypothetical scenario of a slow-onset asthma exacerbation. Of all 1262 asthmatic patients, 39.3% showed adequate self-treatment behaviour (self-adjusting their inhaled or oral steroids when appropriate). Age, asthma-specific outcome expectancies and knowledge were predictive of adequate self-treatment. Adequate self-management behaviour (self-treatment or seeking medical help) was observed in 56.4% of patients. Intentions towards self-management and asthma-specific knowledge were significant. Only knowledge has a relevant influence on both. Asthma-specific knowledge is the only factor that seems relevant for adequate self-management and self-treatment behaviour, which might be explained by the hypothetical nature of the scenario. When patients experience a real asthma exacerbation, self-efficacy expectancies will become more important. Only if knowledge of what to do is present will patients be able to show proper self-management and self-treatment behaviour. Our results suggest that self-treatment guidelines are only effective in combination with patient education, which is important for optimal control of their disease.

Adolescent↗
PubMed2006

[Characteristics of mild asthma: clinical signs and medication use. Position statement of the Mild Asthma Working Group (174)].

OBJECTIVE: To update on the state of knowledge in mild asthma (intermittent and persistent mild asthma, according to the GINA classification) review the literature, and the position statement of the French Mild Asthma Working Group. METHODS: The French Mild Asthma Working Group (11 lung specialists, 4 paediatricians, 1 pharmacologist, and 1 general practitioner) selected, analysed, and summarised the literature on the descriptive epidemiology, physiopathology, clinical signs, and management of mild asthma. The position of the working group on the descriptive epidemiology (causal factors excluded) and the nature of the bronchial inflammation has been presented in a previous article. The present article focuses on the clinical features of mild asthma and the use of medication for it. RESULTS: Mild asthma was more frequent, more symptomatic, and less well controlled in children than in adults. Its generally benign evolution may in some (<10%) cases be complicated by severe episodes. Patients with mild persistent asthma require controller medication every day: permanent low-dose inhaled corticosteroid monotherapy is the reference foundation treatment for persistent mild asthma. CONCLUSIONS: The present findings should help clinicians and guide them in their approach to managing this condition.

Administration, Inhalation↗
PubMed2006

Improvement of asthma control with omalizumab in 2 obese pediatric asthma patients.

BACKGROUND: Dosing of the anti-IgE antibody (omalizumab) in the treatment of allergic asthma depends on serum IgE concentration and body weight. It is unclear whether omalizumab is therapeutically effective in obese patients with difficult-to-control asthma whose body weights fall outside dosing guidelines. OBJECTIVE: To report the efficacy of omalizumab in 2 obese pediatric patients with severe persistent asthma whose high body weights placed them outside current dosing guidelines. METHODS: Omalizumab was given at maximum doses to both patients. Standard asthma therapy was continued throughout the treatment period. Multiple parameters of asthma disease activity were followed at every health encounter for approximately 1 year during and before omalizumab treatment. These parameters included asthma disease severity and activity, pulmonary functions, daily inhaled corticosteroid requirements, systemic steroid rescue, and urgent care and emergency department visits and hospitalizations. RESULTS: While receiving omalizumab, both patients had improvements in asthma disease activity and reduction in systemic steroid requirements. One patient required fewer daily inhaled corticosteroids and achieved total asthma control. CONCLUSION: Patients with difficult-to-treat asthma may benefit from receiving omalizumab even if they fall outside current dosing guidelines because of high body weight.

Administration, Inhalation↗
PubMed2004

The utility of the Health Plan Employer Data and Information Set (HEDIS) asthma measure to predict asthma-related outcomes.

BACKGROUND: The Health Plan Employer Data and Information Set (HEDIS) measures are used extensively to measure quality of care. OBJECTIVE: To evaluate selected aspects of the HEDIS measure of appropriate use of asthma medications. METHODS: Claims data were analyzed for commercial health plan members who met HEDIS criteria for persistent asthma in 1999. The use of asthma medications was evaluated in the subsequent year with stratification by controller medication and a measure of adherence (days' supply). Multivariate logistic regressions were used to evaluate the association among long-term controller therapy for persistent asthma, adherence to therapy, and asthma-related hospitalizations or emergency department (ED) visits, controlling for demographic, preindex utilization, and other confounding characteristics. RESULTS: Of the 49,637 persistent asthma patients, approximately 35.7% were using 1 class of long-term controller medications, 18.4% were using more than 1 class, and 45.9% were not using such medication. More than 25% of the persistent asthma patients did not use any asthma medication in the subsequent year. Patients with low adherence to controller medication had a significantly higher risk (odds ratio [OR], 1.72; 95% confidence interval [CI], 1.42-2.08) of ED visit or hospitalization relative to patients not using any controllers compared with persons with moderate (OR, 0.84; 95% CI, 0.57-1.23) or high (OR, 0.70; 95% CI, 0.34-1.44) adherence. Patients receiving a high days' supply of inhaled corticosteroids had the lowest risk of ED visit or hospitalization (OR, 0.37; 95% CI, 0.05-2.69). CONCLUSIONS: Our findings suggest that refinements to the HEDIS measure method for identifying patients with persistent asthma may be needed.

Adult↗
PubMed2003

What can we learn about asthma from studying occupational asthma?

OBJECTIVE: To review the clinical features and underlying mechanisms of occupational asthma in an attempt to glean insights into various other forms of asthma. DATA SOURCES: Published literature, including consensus guidelines on diagnosis and management of occupational asthma. STUDY SELECTION: This article represents a synthesis of these data sources and the opinion of the author. RESULTS: Occupational asthma may be caused by a variety of mechanisms, including both IgE-dependent and non-IgE-dependent immunological processes. IgE-dependent mechanisms are responsible for reactions to all high-molecular-weight occupational antigens and to some but not all low-molecular-weight antigens. Factors in sensitization and onset include the general genetic predisposition to make IgE and the specific responsiveness of the individual to particular allergens. Once sensitized, the main factor that influences the onset of symptoms is the degree of exposure. In general, the higher the level of exposure, the more likely the sensitized person is to develop asthma. CONCLUSIONS: Occupational asthma can be induced by a variety of agents that appear to use different mechanisms to affect the airway. Studies of the remission of occupational asthma indicate that resolution is a slow process. However, the study of occupational asthma may eventually allow us to identify treatments that will accelerate remission or induce remission in other forms of asthma.

Allergens↗
PubMed2003

Diet and asthma: has the role of dietary lipids been overlooked in the management of asthma?

OBJECTIVE: This article discusses the role of diet in the management of asthma. Readers will gain an understanding of how evolution of the western diet has contributed to increased asthma prevalence and how dietary modification that includes management of dietary lipids may reduce symptoms of asthma. DATA SOURCES: Relevant studies published in English were reviewed. STUDY SELECTION: Medline search to identify peer-reviewed abstracts and journal articles. RESULTS: Asthma and obesity, which often occur together, have increased in prevalence in recent years. Studies suggest adaption of a western diet has not only contributed to obesity, but that increased intake of specific nutrients can cause changes in the frequency and severity of asthma. Increased asthma prevalence has also been proposed to arise from increased exposure to diesel particles or lack of exposure to infectious agents or endotoxins during childhood, generating a biased Th2 immune response, and increased cytokine and leukotriene production. Antagonists directed against these pro-inflammatory mediators include anticytokines and antileukotrienes. A reduction in the levels of inflammatory mediators associated with asthma has also been seen with dietary interventions, such as the administration of oils containing gamma-linolenic acid and eicosapentaenoic acid. CONCLUSIONS: Evidence suggests elevated body mass index and dietary patterns, especially intake of dietary lipids, contribute to symptoms of asthma. Dietary modification may help patients manage their asthma as well as contribute to their overall health.

Adolescent↗