History Of Hay Fever Research Articles

Abstract IA21: Risk prediction models for lung cancer

Abstract IA21: Risk prediction models for lung cancer

Pedestrians' perception of environmental stimuli through field surveys: Focus on particulate pollution

The between perception of individual exposure to different environmental stimuli; microclimate, noise and especially particulate matter (PM) was examined. Microclimate, noise and PM were monitored during field surveys with 260 questionnaire-guided interviews at a road construction site and a traffic site on the UC San Diego campus. The overall comfort was determined primarily by the thermal environment. The air quality was considered to be poor by 42% of the interviewees at the construction site, which was burdened with higher PM counts and sound levels. Overall, higher PM concentrations were correlated with perception of poor air quality. Similarity between the overall air quality and how dusty it feels suggests that visual clues of PM, such as dust, affect the perception of air quality and pollution. The effect of medical or smoking history on the perceived air quality was also examined. People with a medical history of hay fever voted more frequently for poor air quality conditions than those without, whereas current smokers were the least sensitive to ambient air quality conditions. Through the exposure–response relationships between the various perception votes and PM, it was possible to predict perceived air cleanness using the PM count. Understanding the human assessment of environmental stimuli could inform the design and development of urban spaces, in relation to the allocation of uses and activities, along with air quality management schemes.

Advantages of Video Questionnaire in Estimating Asthma Prevalence and Risk Factors for School Children: Findings From an Asthma Survey in American Indian Youth

Objectives. The aims of the present study were to estimate the prevalence and risk factors of asthma among a sample of American Indian youth and to evaluate survey instruments used in determining asthma prevalence and risk factors. Methods. Three hundred and fifty-two adolescents aged 9 to 21 years enrolled in an Indian boarding school completed an asthma screening. The survey instruments were a written questionnaire and a video-illustrated questionnaire prepared from the International Study of Asthma and Allergies in Childhood (ISAAC), school health records, and a health questionnaire. Participants also underwent spirometry testing. Results. The prevalence of self-reported asthma varied from 12.7% to 13.4% depending upon the instrument used and the questions asked. A history of hay fever, respiratory infections, and family history of asthma were found to be risk factors for asthma by all instruments. Female gender and living on a reservation were significantly associated with asthma by some, but not all, instruments. Airway obstruction was highly associated with one asthma symptom (wheeze) shown in the video questionnaire. Associations for most risk factors with asthma were strongest for the video questionnaire. Conclusions. The prevalence of self-reported asthma among these American Indian youth was similar to rates reported for other ethnic groups. The video-based questionnaire may be the most sensitive tool for identifying individuals at risk for asthma.

Atopic disease and risk of non-Hodgkin lymphoma: an InterLymph pooled analysis.

We performed a pooled analysis of data on atopic disease and risk of non-Hodgkin lymphoma (NHL) from 13 case-control studies, including 13,535 NHL cases and 16,388 controls. Self-reported atopic diseases diagnosed 2 years or more before NHL diagnosis (cases) or interview (controls) were analyzed. Pooled odds ratios (OR) and 95% confidence intervals (95% CI) were computed in two-stage random-effects or joint fixed-effects models, and adjusted for age, sex, and study center. When modeled individually, lifetime history of asthma, hay fever, specific allergy (excluding hay fever, asthma, and eczema), and food allergy were associated with a significant reduction in NHL risk, and there was no association for eczema. When each atopic condition was included in the same model, reduced NHL risk was only associated with a history of allergy (OR, 0.80; 95% CI, 0.68-0.94) and reduced B-cell NHL risk was associated with history of hay fever (OR, 0.85; 95% CI, 0.77-0.95) and allergy (OR, 0.84; 95% CI, 0.76-0.93). Significant reductions in B-cell NHL risk were also observed in individuals who were likely to be truly or highly atopic-those with hay fever, allergy, or asthma and at least one other atopic condition over their lifetime. The inverse associations were consistent for the diffuse large B-cell and follicular subtypes. Eczema was positively associated with lymphomas of the skin; misdiagnosis of lymphoma as eczema is likely, but progression of eczema to cutaneous lymphoma cannot be excluded. This pooled study shows evidence of a modest but consistent reduction in the risk of B-cell NHL associated with atopy.

Anesthesia Simulator - Case 5 - Anaphylactic Reaction

Abstract This resource is a case-based simulation on anaphylactic reaction. It features a 22-year-old healthy male presenting for appendectomy. He has a history of hay fever and a penicillin allerg...

Occupational asthma caused byArabidopsis thaliana: a case of laboratory plant allergy

A 36-yr-old male never-smoker with an 8-yr history of hay fever but no past history of asthma undertook a 3-yr research project involving the plant Arabidopsis thaliana. The subject was based in a small laboratory with an attached growing room. After 30 months of research, he began to develop breathlessness within 5-10 min of entering the laboratory. Initial investigations confirmed asthma with airflow obstruction (forced expiratory volume in one second (FEV(1))/forced vital capacity was 3.01/4.75 L; predicted values were 3.67/4.43 L) and increased airway responsiveness. Serial peak expiratory flow measurements showed a work-related pattern. A supervised workplace challenge test led to a fall in FEV(1) from the baseline value of 3.10 L to 1.95 L within 20 min of entering the growing room. Skin-prick solutions were prepared from Arabidopsis leaves and flower heads; positive 4-mm responses were obtained to the flower heads (i.e. to the pollen). Arabidopsis is a member of the Brassicaceae family. It is used extensively in plant biology research as its genome is small, has been fully sequenced and is easily manipulated. The present article represents the first reported case of occupational asthma due to Arabidopsis thaliana.

The Association Between Hay Fever and Stroke in a Cohort of Middle Aged and Elderly Adults

Asthma has been linked to stroke, but it is unknown if hay fever is related to stroke. This study was designed to investigate if there is an association between a reported history of hay fever and stroke during a 4.4-year study period. Analysis was performed of the Atherosclerosis Risk in Communities study, a cohort of middle aged and elderly adults. We examined the association of a reported history of hay fever to the development of stroke. There were 9272 participants meeting our criteria, of which 125 had strokes. Of those with a history of hay fever, 2.2% had a stroke. Of those without a history of hay fever, 1.25% had a stroke. Participants with a history of hay fever had an unadjusted hazard ratio of 1.72 (95% CI, 1.08-2.27) for stroke versus participants without hay fever. Risk of stroke remained significant (hazard ratio, 1.87 [95% CI, 1.17-2.99]) after controlling for age, sex, race, smoking status, body mass index, diabetes, hypertension, alcohol use, and hyperlipidemia. A history of hay fever seems to be a risk factor for stroke, and this association may be an area for future research and intervention.

Airway Responsiveness in Mild to Moderate Childhood Asthma

Airway responsiveness is a prognostic marker for asthma symptoms in later life. To evaluate characteristics responsible for persistence of airway responsiveness in children with asthma. A total of 1,041 children, initially aged 5-12 years, with mild to moderate persistent asthma enrolled in the Childhood Asthma Management Program (CAMP) were studied prospectively for 8.6 +/- 1.8 years with methacholine challenges yearly. Least squares geometric mean models were fit to determine effects of sex and age on airway responsiveness (provocative concentration producing 20% decrease in FEV(1) [PC(20)]). Multiple linear regression analysis was performed to determine factors at baseline and over time, which were associated with PC(20) at end of follow-up. A total of 7,748 methacholine challenges were analyzed. PC(20) increased with age, with boys having greater increase after age 11 years than girls (P < 0.001). The divergence coincided with the mean age for Tanner stage 2. Postpubertal girls had greater airway responsiveness, even after adjustment for FEV(1) and other potential confounders. Although multivariable regression analyses noted a variety of factors that influenced airway responsivness in both sexes, a history of hay fever (beta= -0.30, P = 0.005), respiratory allergy (beta= -0.32, P = 0.006), or recent inhaled corticosteroid usage (beta= -0.18, P = 0.02) were associated with decrements in final log PC(20) only in girls. Airway responsiveness (PC(20)) is more severe in the postpubertal female with asthma than in males. Although there are factors associated with airway responsiveness in both males and females, sex-specific factors may contribute to new insights into asthma pathogenesis.

Risk factors for asthma in adult twins

AbstractIntroduction: This PhD thesis was conducted at the Respiratory and Allergy Research Unit, Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark.Objective: This study was conducted in a population of adult twins to: (i) determine the incidence of asthma; (ii) identify the risk factors for asthma; and (iii) estimate to what extent genetic and environmental factors influence asthma, wheeze, rhinitis, positive skin‐prick test (posSPT) and airway hyper‐responsiveness (AHR).Materials and Methods: The study population was based on the twin cohorts born between 1953 and 1982 that were ascertained from the nationwide Danish Twin Registry. Questionnaire data on multiple traits including asthma and possible risk factors for asthma was collected in 1994 and 2002, defining a population of 19 349 subjects (6090 intact twin pairs) at risk of new asthma. Furthermore, a total of 575 subjects (256 intact pairs and 63 single twins), who either themselves and/or their co‐twins reported a history of asthma at the 2002 questionnaire, were clinically examined.Results: The incidence of asthma was 4.5 and 6.4 per 1000 person‐years, respectively, among males and females (Odds Ratio (OR) = 1.49, P &lt; 0.001). There was a positive association between increasing body mass index (BMI) and risk of asthma for both sexes (OR = 1.05 per unit, P &lt; 0.001). A history of hay fever (OR = 4.2 for males and OR = 3.7 for females, P &lt; 0.001), eczema (OR = 3.5 for males and OR = 2.0 for females, P &lt; 0.001) and both (OR = 6.9 for males and OR = 8.0 for females, P &lt; 0.001) were significant predictors of asthma. Physical exercise was weakly associated with asthma (OR for inactivity = 0.35, P = 0.02), whereas smoking and educational status was not significantly associated with asthma. There was a high genetic similarity between asthma and wheeze (genetic correlation, ρA = 0.96), asthma and rhinitis (ρA = 0.94), wheeze and rhinitis (ρA = 0.95), wheeze and AHR (ρA = 0.85), and rhinitis and posSPT (ρA = 0.92), whereas lower genetic correlations were observed between rhinitis and AHR (ρA = 0.43) and between AHR and posSPT (ρA = 0.59). Traits with a high degree of environmental sharing were asthma and wheeze (environmental correlation, ρE = 0.82), rhinitis and posSPT (ρE = 0.92), and wheeze and posSPT (ρE = 0.71), whereas lower environmental correlations were observed between asthma and rhinitis (ρE = 0.19) and between wheeze and rhinitis (ρE = 0.25).Conclusions: The incidence of asthma in adulthood is high, especially among females. In both sexes, increasing levels of BMI increase the risk of asthma. A substantial portion of adult‐onset asthma is preceded by hay fever and eczema. Asthma, wheeze, rhinitis, AHR and posSPT share, to a large extent, a common genetic aetiology. In particular, asthma and rhinitis are genetically similar, but environmentally distinct. Furthermore, genetic factors mainly explain the co‐occurrence of asthma and posSPT, and rhinitis and posSPT, whereas asthma, but not rhinitis, is closely genetically related to AHR. Finally, asthma and posSPT, and rhinitis and posSPT show similar environmental architectures. These results provide new insights into the aetiology of asthma and may be used to guide the choice of traits for genetic linkage analysis.

Interplay between mutagen sensitivity and epidemiological factors in modulatinglung cancer risk

Few studies have assessed mutagen sensitivity and lung cancer (LC) risk associations in the context of multiple epidemiological risk factors. We evaluated mutagen sensitivity as a susceptibility marker and explored the interplay of the genetic marker and multiple epidemiologic risk factors in modulating LC risk. This largest case-control study included 977 newly diagnosed LC patients and 977 controls, matched by age, gender, ethnicity and smoking status. Cases exhibited significantly higher mutagen sensitivity than controls in bleomycin (0.76 vs. 0.62 breaks/cell, p < 0.001) and benzo[a]pyrene diol epoxide (BPDE) assays (0.70 vs. 0.61 breaks/cell, p < 0.001). Mutagen sensitivity also exhibited dose-response relationship with LC risk in quartile analysis (p for trend <0.001). In smokers, history of emphysema, absence of hay fever history, LC in first-degree relatives, belomycin sensitivity, and high pack-year were identified to be the top 5 significant risk factors in a stepwise logistic regression model (odds ratios (ORs) of 2.69, 1.91, 1.84, 1.73 and 1.67, respectively). Analyses of joint effects of risk factors showed that compared to the reference group, subjects with no exposure to any of the aforementioned risk factors, the ORs for exposure to 1, 2, 3, 4, 5 or more of the risk factors were 1.56, 2.39, 3.75, 6.74 and 17.39, respectively (p for trend <0.001). This study strongly supports mutagen sensitivity as a predisposition factor for LC and demonstrates the importance of assessing multiple risk factors to comprehensively assess LC risk. This new integrative approach should facilitate identification of high-risk subgroups and has important implications in LC prevention.

The relationship between seroatopy and symptoms of either allergic rhinitis or asthma

Epidemiologic data on allergic rhinitis and asthma are frequently based on self-reported symptoms. This cross-sectional study examined the relationship between self-reported symptoms and histories of allergic rhinitis or asthma and a marker of allergic sensitization, allergen-specific IgE. We surveyed 702 pregnant women in Michigan. Blood samples were analyzed for specific IgE to 9 allergens: dust mites (Dermatophagoides farinae and Dermatophagoides pteronyssinus), cat, dog, cockroach, ragweed, timothy grass, egg, and Alternaria alternata. Seratopy was defined as a specific IgE greater than or equal to 0.35 kU/L to any allergen. Seroatopy was found in 66.7% of those with hay fever symptoms, 68.3% with a physician's diagnosis of asthma, and 72.1% of those with both conditions. These results differed significantly from asymptomatic subjects, where 49.8% of patients without hay fever and 50.4% without asthma were seroatopic. Race and education did not modify the relationships. Symptoms related to specific exposures were modest predictors of positive specific IgE to related allergens (positive predictive values from 26.5% to 50.3%). Self-reported symptoms of allergic rhinitis or asthma were significantly associated with allergic sensitization, but the odds ratios were of relatively low magnitude for this historical information to be considered evidence of current allergic sensitization. A 66% to 68% probability existed that those with symptoms of allergic rhinitis or asthma would have a positive specific IgE test. Self-reported histories of hay fever or asthma alone are only modest predictors of allergic sensitization. When knowledge of allergic sensitization is important, information beyond self-reported symptoms is necessary.

Topographic Indications of Emerging Keratoconus in Teenage New Zealanders

To screen a population of teenagers for emerging topographic signs of keratoconus (KC), with particular reference to ethnicity. Corneal topography, visual acuity, and an environmental risk factor analysis were included in a screening program designed to identify early indications of potential KC in teenagers. Two schools from central North Island, New Zealand, were invited to participate: one with predominantly Maori/Polynesian students and the other with students of mainly European descent. A total of 198 Maori/Polynesian, 16.8 +/- 1.05 years of age, and 243 European students, 16.2 +/- 1.3 years of age, participated in the study. Corneal topography suggestive strongly of KC was evident in 3 Maori/Polynesian [1.2%; 95% confidence interval (CI): 0.3-4.3] and no European students (0%; 95% CI, 0%-1.5%). Anomalous corneal topography reminiscent of emerging KC in at least 1 eye were found in 19% (95% CI, 15.6%-22.9%). A significant difference (P = 0.0014) in the percentage of suspected KC was found between European students (12.9%; 95% CI, 9.2%-17.9%) and Maori/Polynesian students (26.9%; 95% CI, 21.0%-33.7%). In multivariate analyses, the significant independent predictors of probable or suspected KC included being Maori/Polynesian [odds ratio (OR) = 2.1; 95% CI, 1.25-3.54; P = 0.0052], increasing age (OR = 1.4; 95% CI, 1.10-1.80; P = 0.0067), and a history of hayfever (OR = 2.0; 95% CI, 1.16-3.59; P = 0.013). Topographical indicators that were associated significantly with suspected KC included central keratometry (P < 0.0001), astigmatism (P = 0.014), and inferior-superior asymmetry (P < 0.0001). Although only a longitudinal study will determine the proportion of true KC candidates, these data provide evidence of ethnicity-related differences in corneal topography in teenage New Zealanders.

Hand Dermatitis Risk Factors Among Clinical Nurses in Japan

The purpose of this study was to establish hand dermatitis (HD) risk factors among Japanese nurses. A questionnaire was administered to 1,162 clinical nurses, from whom 860 replies were received (response rate of 74.0%). Their overall HD prevalence was 53.3%. Several risk factors were identified: using latex gloves (odds ratio [OR] 1.9), allergies in adulthood (OR 2.7), urticaria as an adult (OR 1.5), atopic dermatitis as an adult (OR 2.7), any allergies to latex products (OR 5.2), skin irritation following contact with latex (OR 4.1), contact dermatitis following contact with latex (OR 3.5), family history of hay fever (OR 1.6), and family history of atopic dermatitis (OR 1.9). The use of hand cream was associated with a 50% reduction in HD risk (OR 0.5). In this study, we found that Japanese clinical nurses suffer a significant occupational burden from HD. As such, it is essential that hospital managers consider interventions to reduce this troublesome occupational disease among clinical nurses in Japan, as elsewhere.

Never smokers and lung cancer risk: A case‐control study of epidemiological factors

We performed an analysis of potential epidemiological risk factors for lung cancer using data from 280 cases and 242 hospital-based controls, all lifetime never smokers (those who had smoked <100 cigarettes in their lifetimes) and frequency matched on age, gender and ethnicity. The data on demographic characteristics, medical history of respiratory diseases (asthma, emphysema, pneumonia and hay fever), weight and height, family history, female characteristics and environmental tobacco smoke (ETS) and dust exposure were derived from personal interviews. We performed a logistic regression analysis of these variables adjusting for age, gender, ethnicity, income and years of education. Exposure to ETS (OR = 2.08, 95% CI [1.25-3.43]) and dusts (OR = 2.43, 95% CI [1.53-3.88]) were associated with significantly increased risk. In the analysis for joint effects, exposure to both ETS and dusts conferred a higher risk (OR = 3.25, 95% CI [1.58-6.70]) than exposure to either alone. Family history of any cancer with onset before age 50 in at least 1 first degree relative was a significant risk predictor (OR = 1.70, 95% CI [1.10-2.64]). Individuals with a self-reported physician-diagnosed history of hay fever, but not asthma, had a decreased lung cancer risk (OR = 0.57, 95% CI [0.35-0.92]). In the multivariate analysis, exposure to ETS and dusts, and family history of cancer with onset before age 50 were significant risk factors, while a history of hay fever (occurring without asthma) was significantly protective.

Cancer Mortality among US Men and Women with Asthma and Hay Fever

The relation between self-reported physician-diagnosed asthma and/or hay fever and cancer mortality was explored in a prospective cohort study of 1,102,247 US men and women who were cancer-free at baseline. During 18 years of follow-up, from 1982 to 2000, there were 81,114 cancer deaths. Cox proportional hazards models were used to obtain adjusted relative risks for all cancer mortality and for cancer mortality at 12 sites associated with allergy indicators. There were significant inverse associations between a history of both asthma and hay fever and overall cancer mortality (relative risk (RR) = 0.88, 95% confidence interval (CI): 0.83, 0.93) and colorectal cancer mortality (RR = 0.76, 95% CI: 0.64, 0.91) in comparison with persons with neither of these allergic conditions. A history of hay fever only was associated with a significantly lowered risk of pancreatic cancer mortality, and a history of asthma only was associated with a significantly lowered risk of leukemia mortality. In never smokers, these associations persisted but were no longer significant. Results for mortality from cancer at other sites were less consistent. Collectively, these results suggest an inverse association between a history of allergy and cancer mortality; however, the strength of evidence for this association is limited.

Atopic Profiles, Familial Histories, and Coexisting Conditions Associated With Hand Eczema

Many of the eczema cases seen by dermatologists involve the hands. The discomfort and embarrassment of hand dermatitis in any of its forms may compromise a patient's quality of life, causing frustrated attempts to identify the cause of the disease and engendering disappointment with treatment failures. The authors assessed the severity scores for each patient, personal and familial histories of atopy, coexisting conditions, triggers of irritation, types of treatments, and their success rates. The authors administered a comprehensive survey to 50 consecutive patients presenting with eczematous dermatitis on the ventral aspect of the hands. The authors used a novel hand eczema severity index and a questionnaire that assessed personal and familial histories of atopy as well as coexisting conditions, triggers, and sources of irritation; types of treatments employed; and success rates. Patients were also encouraged to complete a composite quality of life assessment. Results reveal a high frequency of personal and familial atopy, a 58% prevalence of contact allergy, a 67.4% history of hay fever, 25.6% cases of asthma, and a 44% incidence of fungal infection, which was one of the most common coexisting conditions. Both topical immunomodulators and topical corticosteroid therapy treatments demonstrated an impressive efficacy. An overlap should be considered when clinical symptoms and histological results vacillate between psoriasis and eczema.

The Incidence of Asthma in Young Adults

Longitudinal data on adult asthma are sparse. The objectives of this study were to determine the incidence of asthma and to establish the risk factors for the development of asthma in subjects who were 12 to 41 years old over an 8-year period. From birth cohorts over the period 1953 to 1982 in The Danish Twin Registry, 19,349 subjects with no history of asthma, as determined by a questionnaire-based survey in 1994, answered a follow-up questionnaire in 2002. The subjects were regarded as incident asthma cases when answering "yes" to the question "Do you have, or have you ever had asthma?" in 2002, and "no" to the same question in 1994. A total of 838 cases (4.3%) of new asthma were identified in 2002. The incidence rates of asthma were 4.5 and 6.4 per 1,000 person-years, respectively, among male and female subjects. For all ages, the probability of adult-onset asthma was greater for female subjects (odds ratio [OR], 1.49; p < 0.001), and for both sexes there was a slow decline in probability with increasing age. There was a positive association between increasing body mass index (BMI) and risk of adult-onset asthma applying to both sexes (OR, 1.05 per unit; p < 0.001). Furthermore, positive associations were found between incident asthma and a history of hay fever (OR: male subjects, 4.2; female subjects, 3.7; p < 0.001), eczema (OR: male subjects, 3.5; female subjects, 2.0; p < 0.001), and both (OR: male subjects, 6.9; female subjects, 8.0; p < 0.001). There is a continuing high incidence of asthma past childhood that is most pronounced among female subjects. Increasing levels of BMI are associated with a greater likelihood of developing asthma for both sexes. A substantial portion of cases of adult asthma is preceded by upper airway allergic symptoms and/or eczema, thus indicating a shared pathogenesis.

THE RELATIONSHIP BETWEEN EXHALED NITRIC OXIDE AND ALLERGIC SENSITIZATION IN A RANDOM SAMPLE OF SCHOOLCHILDREN

Van Amsterdam JGC, Janssen NAH, de Meer G, et al. Clin Exp Allergy. 2003;33:187–191To determine whether there is a relationship between levels of exhaled nitric oxide (eNO) and sensitization to common allergens.A convenience sample of 450 schoolchildren (7–12 years of age), of a total random sample of 2504 children in the Netherlands, were enrolled.Children were recruited from 7 public schools and were assessed for allergen sensitization with skin prick testing and/or specific immunoglobulin E (IgE) radioallergosorbent testing (RAST) with common environmental allergens, including dust mite, cat, tree, grass, dog, and mold allergens. eNO was measured with a standard protocol. Families were also asked to complete a questionnaire regarding the home environment, family composition, education, and passive smoke exposure. Associations between eNO levels and sensitization to common allergens were analyzed with adjustments for age, gender, gas cooking, unvented water heaters, passive smoke exposure, and having a cold during sampling.Of the total 450 children studied, 9% had a lifetime history of asthma, with 10% reporting wheeze in the previous year, 8.2% had a history of hay fever, and 29.1% had a history of eczema ever. Of the 319 children who underwent skin prick testing, 29.5% had ≥1 positive test result, 21.9% for indoor allergens and 15% for outdoor allergens. Of the 229 children who underwent specific IgE RAST, 32.3% had ≥1 positive test result, 23.1% for indoor allergens and 21.8% for outdoor allergens. The geometric mean level of eNO was ∼1.5 times higher among children sensitized to indoor allergens, compared with nonsensitized children (P < .05), and this was increased to 2 times higher when a cutoff value of ≥2 positive tests was used for either indoor or outdoor allergen sensitivity. eNO levels gradually increased with increases in positive allergen tests. There was no association between eNO levels and current pet ownership. The association between allergen sensitization and eNO was much stronger among children with a history of wheezing, compared with children without wheezing (relative increases of 1.24–1.47 among nonwheezers and 1.56–3.44 among wheezers).This study found a positive association between eNO levels and levels of allergen sensitivity in a random sample of schoolchildren in the Netherlands. The association was stronger among children with sensitization to indoor allergens and children with a history of wheezing. Association with sensitization to outdoor allergens was not as strong, which the authors proposed might be related to the larger particle size of pollens preventing their entry into lower airways. The mechanism of these elevated eNO levels is not known, but the authors proposed that exposure to allergens could lead to inflammatory changes in the lower airway without causing signs of clinical asthma.The authors concluded that allergen sensitization was associated with elevated levels of eNO in a random sample of children, most without outward signs of asthma.eNO has been shown in many studies to be a useful marker of inflammation among asthmatics, but this study demonstrated an association between atopy and eNO levels. It has been suggested that eNO may be a useful screening test for asthma, and perhaps some of these asymptomatic atopic patients are evolving asthmatics. Although eNO devices have received Food and Drug Administration approval, their cost has limited their use to research settings to date.

Assessing individual employee risk factors for occupational asthma in primary aluminium smelting

Aims: To assess the significance of individual risk factors in the development of occupational asthma of aluminium smelting (OAAS). Methods: A matched case-control study nested in a cohort of 545...

Asthma and allergic rhinitis in Quebec children.

The Health and Social Survey of Quebec Children and Youth, conducted on representative samples of children nine, 13 and 16 years of age, provided data on the prevalence and determinants of asthma and allergic rhinitis in Quebec. To determine the prevalence of asthma and allergic rhinitis among children in the province of Quebec and to identify the determinants of these pathologies. Three groups of more than 1100 children aged nine, 13 and 16 years were recruited. Respiratory symptoms were documented using the International Study of Asthma and Allergies in Childhood questionnaire. Questions enquiring about family income, smoking, degree of urbanization of the child's school's location and various variables related to indoor air were also included. The comparisons of proportions were done using the chi2 test. The prevalence rates for reported history of asthma varied from 14% to 15% depending on the age group. The prevalence of wheezing in the past year was 7% to 8%. Asthma was the primary cause of the limitation of activities due to a health problem in nine- and 13-year-old Quebecers, and the second most common cause in 16-year-old Quebecers. The prevalence of rhinitis, rhinoconjunctivitis and reported history of hay fever increased with age, reaching 28.0%, 15.9% and 21.1%, respectively, in the 16-year-old group. The prevalence of asthma and wheezing was associated with family history and allergies, and inversely related to family income. The prevalence of childhood asthma is high in the province of Quebec. It is a major cause of the limitation of activities due to a health problem for young Quebecers. A family history of asthma and an atopic predisposition are important determinants in the development of asthma in Quebec.