Bronchial hyperresponsiveness in children with atopic rhinitis: a 7-year follow-up

BACKGROUND: A high prevalence of bronchial hyperresponsiveness (BHR) was found in atopic subjects with rhinitis. Those subjects may be at higher risk for developing bronchial asthma. We evaluated, in a 7-year follow-up, BHR and atopy in a homogeneous population of nonasthmatic children with allergic rhinitis (AR), and their role in asthma development. METHODS: Twenty-eight children (6-15 years) with AR were studied. At enrollment (T(0)), skin tests, total serum IgE assay, peak expiratory flow (PEF) monitoring and methacholine (Mch) bronchial challenge were performed. BHR was computed as the Mch dose causing a 20% forced expiratory volume (FEV)(1) fall (PD(20)FEV(1)) and as dose-response slope (D(RS)). Subjects were reassessed after 7 years (T(1)) using the same criteria. RESULTS: At T(0), 13 children (46%), showing a PD(20)FEV(1) <1526 microg of Mch, had BHR (Mch+), although PEF variability (PEFv) was within normal limits. None of the children with negative methacholine test developed bronchial asthma after 7 years. Of the 13 Mch+, only two reported asthma symptoms after 7 years. No significant change was seen in the other parameters of atopy considered. CONCLUSION: Children with allergic rhinitis present a high prevalence of BHR. Nevertheless, their PEFv is normal and the rate of asthma development low.     

Prevalence and severity of asthma, rhinitis, and atopic eczema in 13- to 14-year-old schoolchildren from the northeast of England.

OBJECTIVE: To investigate the prevalence and severity of asthma, rhinitis, and atopic eczema in schoolchildren from the northeast of England. METHODS: We randomly selected 3,000 children from 80 schools. We used the ISAAC (International Study of Asthma and Allergies in Childhood) written questionnaire. RESULTS: The lifetime prevalence rates of symptoms were: rhinitis, 32.8%; wheezing, 31.3%; hay fever, 23.7%; and self-reported asthma, 22.3%. Rhinitis was reported by 53% and 61% of boys and girls with asthma, respectively. Girls 13 to 14 years of age had higher prevalence rates of asthma, rhinitis, and eczema symptoms than boys; a reverse sex ratio has been shown in this age group. Atopic eczema was reported by 32% of boys with asthma and 37% of girls with asthma. CONCLUSIONS: The prevalence rates of reported asthma, and symptoms suggestive of asthma, were higher than those previously reported in UK children. The present study would be a suitable baseline for monitoring future trends in the prevalence and severity of asthma and allergic disorders among these children, and provides a framework for further etiologic research into the genetics, lifestyle, environmental, and medical care factors affecting these conditions.     

Bronchial hyperresponsiveness in young children with allergic rhinitis and its risk factors

BACKGROUND: Subjects with allergic rhinitis but no clinical evidence of asthma have greater bronchial hyperresponsiveness (BHR), and several factors have been implicated as its determinants. However, studies in young children are lacking. The aims of this study were to evaluate the prevalence of BHR in young children with allergic rhinitis and to investigate its risk factors. METHODS: Methacholine bronchial challenges were performed in 4- to 6-year-old nonasthmatic children with allergic rhinitis (n = 83) and in healthy nonatopic controls (n = 32), using a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. Subjects were considered to have BHR when they had end-point concentrations of methacholine 相似文献   

Time trends in asthma and wheeze in Swedish children 1996–2006: prevalence and risk factors by sex

Background:  Recent data suggest that the previously rising trend in childhood wheezing symptoms has plateaued in some regions. We sought to investigate sex-specific trends in wheeze, asthma, allergic conditions, allergic sensitization and risk factors for wheeze.
Methods:  We compared two population-based cohorts of 7 to 8-year olds from the same Swedish towns in 1996 and 2006 using parental expanded ISAAC questionnaires. In 1996, 3430 (97%) and in 2006, 2585 (96%) questionnaires were completed. A subset was skin prick tested: in 1996, 2148 (88%) and in 2006, 1700 (90%) children participated.
Results:  No significant change in the prevalence of current wheeze ( P  = 0.13), allergic rhinitis ( P  = 0.18) or eczema ( P  = 0.22) was found despite an increase in allergic sensitization (20.6–29.9%, P  < 0.01). In boys, however, the prevalence of current wheeze (12.9–16.4%, P  < 0.01), physician-diagnosed asthma (7.1–9.3%, P  = 0.03) and asthma medication use increased. In girls the prevalence of current symptoms and conditions tended to decrease. The prevalence of all studied risk factors for wheeze and asthma increased in boys relative to girls from 1996 to 2006, thus increasing the boy-to-girl prevalence ratio in risk factors.
Conclusions:  The previously reported increase in current wheezing indices has plateaued in Sweden. Due to increased diagnostic activity, physician diagnoses continue to increase. Time trends in wheezing symptoms differed between boys and girls, and current wheeze increased in boys. This was seemingly explained by the observed increases in the prevalence of risk factors for asthma in boys compared with girls. In contrast to the current symptoms of wheeze, rhinitis or eczema, the prevalence of allergic sensitization increased considerably.     

Wheezing in relation to atopy and environmental factors in Estonian and Swedish schoolchildren

Background The prevalence of asthma and allergic diseases is significantly lower in post socialist Eastern Europe than in Western industrialized countries. The reason for this difference is largely unknown. Different types of childhood wheezing could be related to different risk factors. Objective To compare the prevalence of respiratory symptoms, asthma and atopic diseases among Estonian and Swedish schoolchildren and to evaluate characteristics for wheezing in the two countries. Methods In a prevalence study, population‐based random samples of 10–11‐year‐old schoolchildren in Tallinn (n = 979), Estonia and in Linköping (n = 911) and Östersund (n = 1197), Sweden were studied by a parental questionnaire and skin prick tests (SPT). All 275 children with wheeze in the past 12 months and 710 randomly selected controls within the original cohorts were invited to a case‐control study involving a parental questionnaire, examination for flexural dermatitis and bronchial challenge with hypertonic saline. The study adhered to the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Results The prevalence of current wheezing was similar (8–10%) in the three centres, while diagnosed asthma and atopic symptoms were more common in Sweden and cold‐related respiratory symptoms were more prevalent in Estonia. Frequent wheezing was more common in Sweden than in Estonia (but significantly so only in Östersund). Wheezing children in Sweden had a high rate of positive SPT (49% in Linköping and 58% in Östersund) bronchial hyper‐responsiveness (BHR) (48% in Linköping and Östersund) and anti‐asthmatic treatment (63% in Linköping and 81% in Östersund). In Estonia, the proportion of wheezing children with positive SPT, BHR and anti‐asthmatic treatment was only 26%, 13% and 17%, respectively. Domestic crowding was inversely related to wheezing in one of the study areas (Östersund). The mean baseline forced expiratory volume in one second (FEV₁) was higher in Estonia than in Sweden, both in wheezing and non‐wheezing children. Conclusions Our study suggested that although wheezing symptoms were equally common in Estonia and Sweden, they were less severe in Estonia. More frequent symptoms and a high rate of atopy, BHR and anti‐asthmatic medication characterized wheezing children in Sweden. In contrast, BHR, atopy and medication were uncommon among wheezing children in Estonia.     

Respiratory symptoms, bronchial hyper-responsiveness, and eosinophilic airway inflammation in patients with moderate-to-severe atopic dermatitis

BACKGROUND: Patients with atopic dermatitis (AD) often have symptoms suggestive of asthma or rhinitis. The prevalence and signs of respiratory disease in AD patients have been studied to a limited extent. OBJECTIVES: To assess the prevalence and clustering of respiratory symptoms, bronchial hyper-responsiveness (BHR), and eosinophilic airway inflammation in patients with moderate-to-severe AD. METHODS: Eighty-six consecutive patients with moderate-to-severe AD and 49 randomly selected control subjects without AD were studied by questionnaire, flow volume spirometry, histamine challenge to detect BHR, induced sputum test to detect eosinophilic airway inflammation, and skin prick tests (SPTs) and total serum immunoglobulin (Ig)E measurements to detect atopy. RESULTS: The patients with AD showed increased risk of physician-diagnosed asthma (36% vs. 2%, odds ratio (OR) 10.1, confidence interval (CI) 1.3-79.7, P=0.03), physician-diagnosed allergic rhinitis (AR) (45% vs. 6%, OR 4.5, CI 1.2-16.7, P=0.02), BHR (51% vs. 10%, OR 5.5, CI 1.5-20.1, P=0.01), and sputum eosinophilia (81% vs. 11%, OR 76.1, CI 9.3-623.5, P<0.0001) compared with the control subjects. In AD patients, elevated s-IgE and positive SPTs were associated with the occurrence of physician-diagnosed asthma and AR, BHR, and the presence of sputum eosinophilia. CONCLUSIONS: BHR and eosinophilic airway inflammation are more common in patients with AD than in control subjects. The highest prevalences were seen in patients with AD who were SPT positive and had high IgE levels. Longitudinal studies are needed to assess the outcome of patients with signs of airway disease, in order to identify those who need early initiation of asthma treatment.     

Factors influencing symptom expression in children with bronchial hyperresponsiveness at 10 years of age

OBJECTIVES: We sought to identify factors associated with wheezing symptoms in children found to have bronchial hyperresponsiveness (BHR) at 10 years of age. METHODS: Children were seen at birth, 1, 2, 4 and 10 years of age in an entire population birth cohort study (n = 1456). At each stage information was collected prospectively on genetic and environmental risk factors for BHR. Skin prick testing was performed at 4 and 10 years of age. Spirometry and methacholine bronchial challenge were conducted at 10 years of age when BHR was considered present if PC(20) FEV(1) was < 4.0 mg/mL. In children with BHR at 10 years of age, factors independently associated with current wheezing were determined by logistic regression. RESULTS: BHR was identified in 169 10-year-olds at bronchial challenge, 55.6% of whom manifested current wheeze. In children with BHR, current wheezers had higher Log(10) total IgE and greater BHR than those who had never wheezed. Symptomatic BHR was independently associated with atopic sensitization (P <.001) and maternal asthma (P =.011) at 10 years of age. If only factors present in the first 4 years of life were considered, parental smoking at 4 years of age (P =.021), maternal asthma (P =.017), and atopic sensitization at 4 years of age (P =.004) were independently associated with symptomatic BHR at 10 years of age. CONCLUSIONS: Symptomatic BHR is associated with greater degrees of BHR and higher total IgE. Heredity, atopy, and environmental exposure might influence symptom expression in children with BHR.     

Prevalence of wheeze, bronchial hyper-responsiveness and asthma in the elderly Chinese

BACKGROUND: Asthma is a common health problem affecting patients of all ages. Because of the ease of sampling, epidemiological studies have concentrated mainly on the paediatric and general population. OBJECTIVE: This study aimed to determine the prevalence of wheeze, bronchial hyper-responsiveness and asthma amongst our elderly population and deduce any clinical and laboratory risk factors that might identify elderly asthmatics at an earlier stage. METHODS: Two thousand and thirty-two elderly Chinese aged > or = 70 years, randomly selected from a registered list of all recipients of Old Age and Disability Allowances in Hong Kong, were administered a questionnaire on lung health. Two hundred and fifty subjects were invited to attend our laboratory for skin tests and pulmonary function tests and 179 agreed. Of these, 173 (96.6%) and 176 (98.3%) had eosinophil count and serum IgE levels measured, respectively. Two definitions of asthma were used: (1) bronchial hyper-responsiveness (BHR) plus current wheeze, and (2) history of wheezing without previous diagnostic labels of emphysema or chronic bronchitis. RESULTS: Fifteen patients (out of 179: 8.4%) reported wheezing over the past 1 year. Fifty-one patients (28.5%) demonstrated BHR on spirometry or histamine challenge tests. Seven patients had both symptoms of wheezing and evidence of BHR. The prevalence of asthma using this definition is therefore 3.9% (95% CI 1.6-7.9%). Nine patients had symptoms of wheezing without previous diagnostic labels of chronic bronchitis or emphysema and, using this definition, the prevalence is 5.0% (95% CI 2.3-9.3%). Using multiple logistic regression studies, sex, social class, age, smoking habits, serum IgE levels and eosinophil counts did not predict a diagnosis of asthma using either definition. We found no association between a positive skin test and any respiratory symptoms or illnesses including asthma. CONCLUSION: Wheeze, bronchial hyper-responsiveness and asthma are prevalent amongst our elderly population. However, there were no identifiable demographic and laboratory risk factors in this study that may help us predict a diagnosis of asthma.     

The prevalence of allergic conditions and immediate skin test reactions among Finnish adolescents

The purpose of the study was to determine the skin reactivity of 14–16-year-old adolescents to common allergens and its connections with the occurrence of bronchial wheezing, asthma, allergic rhinitis and atopic eczema. The series consisted of 218 persons living in south-eastern Finland. All the persons who took part in the study filled out a questionnaire concerning symptoms of any allergy. They were prick skin-tested with eight common allergens and examined clinically by the author. Positive skin test reactions were observed in sixty-six cases (31%), forty-one of which (62%) had past or present allergic symptoms. Symptoms indicating past or current allergy were observed in seventy persons (32%). 59% of the young people who had or had had allergic disorders were found to have a positive skin test; the figure for the asymptomatic group was 17%. Allergic rhinitis was most clearly connected with the positive skin test. 83% of those with rhinitis had a positive skin test, whereas the figure for bronchial wheezing and asthma was 70% and for eczema 44%. The prevalence of allergic symptoms and skin test positivity was about the same between the sexes, but the boys had experienced bronchial wheezing twice as often as the girls. This study shows that the prevalence of allergic symptoms, when the mild manifestations are also taken into account, is higher in Finland than is assumed. The occurrence of skin test positivity in the age groups examined is about the same as that observed in previous studies on this subject.     

Bronchial hyperresponsiveness in two populations of Australian schoolchildren. III. Effect of exposure to environmental allergens

Two populations of schoolchildren, one living in an area where the predominant allergens are house dust mites and the other in an area where the predominant allergens are pollens, were studied to investigate in more detail the associations between atopy, bronchial hyperresponsiveness (BHR) and symptoms of asthma. The prevalence of atopy (39%) was the same in both towns but the prevalence of BHR was higher in the inland 'pollen' area (19% vs 15%). Atopic children had an increased risk of having BHR and, to a lesser extent, respiratory symptoms, diagnosed asthma and hay fever. The risk of BHR was further increased in children atopic to both pollens and house dust mites, and in children with a high index of atopy (derived from the number and size of the skin reactions to four allergen groups). In addition, the relationship between atopy and BHR was quantitative in that the severity of BHR increased with the severity of atopy. We conclude that there is not a direct causal relationship between atopy and BHR but there may be a common mechanism involved in their development. It appears that, within the atopic population, the type of allergen to which the individual is sensitized, the quantity of aeroallergen present in the environment and the degree of atopy, as measured by the number and size of the skin reactions, are all factors that may interact to increase the risk of BHR.     

A prospective study of bronchial hyperresponsiveness and respiratory symptoms in a population of Australian schoolchildren

To examine the relationship between bronchial hyperresponsiveness (BHR) and respiratory symptoms associated with asthma, we studied a sample of 380 schoolchildren on three occasions at 2-yr intervals. The age of the children at the first study was 8-10 yr. Respiratory symptoms history was assessed by questionnaire, BHR was measured by a histamine inhalation test and atopy was assessed by skin-prick tests to 13 allergens. The cumulative prevalence of BHR in this sample was 27%. The severity of BHR was categorized as severe, moderate, mild or slight. The distribution of severe, moderate and mild BHR was similar at each of the studies. At the third study, when the children were aged 12-14 yr, the prevalence of slight BHR decreased. Children with severe or moderate BHR at age 8-10 yr were atopic, reported current symptoms during the 4 yr of the study and had a high prevalence of severe or moderate BHR in later studies. In this group, 87% of children had current respiratory symptoms and 73% were using asthma medication at age 12-14 yr. In children with mild or slight BHR when first studied, the prevalence of atopy, continuing respiratory symptoms and medication use was much lower. We conclude that severe or moderate BHR is an important risk factor for ongoing morbidity and that comparisons of the prevalence of this severity of BHR in populations may be more informative than comparisons of BHR defined by present criteria.     

Prevalence and severity of symptoms of asthma, allergic rhinitis, and eczema in 10- to 15-year-old schoolchildren in central Taiwan

The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was distributed through 14 schools and was completed by 11,874 students out of which are parents of 4,167 children aged between 10 and 12 years old and 7,677 older children aged between 13 and 15 years in central Taiwan. The overall cumulative and 12-month prevalence of wheezing, rhinitis, and eczema were 7.4%, 43.0%, and 7.2%, respectively. It was shown that boys had significantly higher prevalence of wheezing and rhinitis (p < 0.001 and p = 0.001) when compared to girls in central Taiwan. The study also found that prevalence rates among younger children with symptoms of wheezing, rhinitis, and recurrent itchy rash in the past 12-month (8.2%, 44.4%, and 8.8%) were higher than that among older children (6.9%, 42.2%, and 6.3%, respectively). In conclusion, boys had significantly higher prevalence of wheezing and rhinitis than girls while younger children tend to have higher prevalence of the disorders than those that are older in age.     

Relationship Between Atopy and Bronchial Hyperresponsiveness

Both atopy and bronchial hyperresponsiveness (BHR) are characteristic features of asthma. They are also found among non-asthmatic subjects, including allergic rhinitis patients and the general population. Atopy and BHR in asthma are closely related. Atopy induces airway inflammation as an IgE response to a specific allergen, which causes or amplifies BHR. Moreover, significant evidence of the close relationship between atopy and BHR has been found in non-asthmatic subjects. In this article, we discuss the relationship between atopy and BHR in the general population, asthmatic subjects, and those with allergic rhinitis. This should widen our understanding of the pathophysiology of atopy and BHR.     

Fast foods – are they a risk factor for asthma?

BACKGROUND: Lifestyle changes over the last 30 years are the most likely explanation for the increase in allergic disease over this period. AIM: This study tests the hypothesis that the consumption of fast food is related to the prevalence of asthma and allergy. METHODS: As part of the International Study of Asthma and Allergies in Childhood (ISAAC) a cross-sectional prevalence study of 1321 children (mean age = 11.4 years, range: 10.1-12.5) was conducted in Hastings, New Zealand. Using standard questions we collected data on the prevalence of asthma and asthma symptoms, as well as food frequency data. Skin prick tests were performed to common environmental allergens and exercise-induced bronchial hyperresponsiveness (BHR) was assessed according to a standard protocol. Body mass index (BMI) was calculated as weight/height2 (kg/m2) and classified into overweight and obese according to a standard international definition. RESULTS: After adjusting for lifestyle factors, including other diet and BMI variables, compared with children who never ate hamburgers, we found an independent risk of hamburger consumption on having a history of wheeze [consumption less than once a week (OR = 1.44, 95% CI: 1.06-1.96) and 1+ times a week (OR = 1.65, 95% CI: 1.07-2.52)] and on current wheeze [consumption less than once a week (OR = 1.17, 95% CI: 0.80-1.70) and 1+ times a week (OR = 1.81, 95% CI: 1.10-2.98)]. Takeaway consumption 1+ times a week was marginally significantly related to BHR (OR = 2.41, 95% CI: 0.99-5.91). There was no effect on atopy. CONCLUSIONS: Frequent consumption of hamburgers showed a dose-dependent association with asthma symptoms, and frequent takeaway consumption showed a similar association with BHR.     

A familial predisposition in bronchial hyperresponsiveness among patients with allergic rhinitis

Background: Nonasthmatic subjects with allergic rhinitis often have bronchial hyperresponsiveness (BHR). The mechanisms responsible for BHR in asthma include genetic predisposition and airway inflammation, but the causes of BHR in allergic rhinitis are poorly understood. Objective: The aim of this study was to investigate whether there is a familial predisposition in allergic rhinitis–associated BHR. Methods: One hundred fifteen children with allergic rhinitis (probands) and their family members underwent methacholine bronchial challenge and skin prick tests with airborne allergens. The probands were divided into 2 groups: BHR(+) (methacholine PC₂₀ <18 mg/mL determined by the dosimeter method; n = 42) and BHR(–) (n = 73). Results: The overall prevalence of BHR was higher in family members of BHR(+) probands than in those of BHR(–) probands (23.3% [27 of 116] vs 10.5% [21 of 200], P < .01). In mothers, this difference was marked (21.4% vs 8.2%, P < .05); a similar trend was observed in fathers (16.7% vs 6.8%) and siblings (34.4% vs 18.5%), although the differences did not reach significance (.05 < P < .1). The bronchial responsiveness index (BR index), a continuous variable derived from the results of methacholine challenge, was significantly higher among family members of the BHR(+) group than those of the BHR(–) group. Furthermore, even when only family members without BHR were considered, the BR index was significantly higher among those (n = 89) of the BHR(+) group than those (n = 179) of the BHR(–) group. There was no difference in atopic status as assessed by the prevalence of atopy (or atopy index) between family members of the BHR(+) group and the BHR(–) group. Conclusion: Our results indicated that there is a significant familial predisposition for BHR among patients with allergic rhinitis. Further studies are needed to elucidate whether genetic factors play a role in allergic rhinitis–associated BHR. (J Allergy Clin Immunol 1998;102:921-6.)     

Prevalence of asthma and other allergic diseases in an adolescent population: association with gender and race.

OBJECTIVES: To estimate the prevalence and severity of asthma in an adolescent population by sex and race. METHODS: Cross-sectional, population-based survey of school children. SETTING: Midwestern city experiencing damage from the 1993 Mississippi River flood. Participants: 2,693 children attending grades 7 to 12. MEASUREMENTS: Questions from the International Study of Asthma and Allergies in Childhood (ISAAC). RESULTS: Two thousand six hundred ninety-three children were surveyed, for a response rate of 90%. In this population, 16.4% reported having ever been diagnosed with asthma; 25% reported wheezing in the last 12 months; 32% reported symptoms of rhinitis in the last 12 months; and 22% reported ever having hay fever. The prevalence rate for current asthma was 12.6%. Female students had significantly greater prevalence rates for current asthma (16.4% vs 9.0%, OR = 1.85); ever-diagnosed asthma (18.5% vs 14.3%, OR = 1.36); wheezing > or = 4 times in the last 12 months (12.0% vs 5.6%, OR = 1.95); current rhinitis (38.7% vs 25.4%, OR = 1.73); and hay fever (26.4% vs 18.4%, OR = 1.57). All associations with sex remained significant, except ever-diagnosed asthma, after controlling for other known risk factors in logistic regression. African-Americans had higher prevalence rates than other races with differences reaching statistical significance for ever-diagnosed asthma and current asthma; however, these relationships did not remain significant after controlling for other known risk factors in logistic regression. CONCLUSIONS: Our prevalence rates were similar to those reported by other studies that used the ISAAC questionnaire. Female students reported significantly more asthma, wheezing, rhinitis, and hay fever than male students. Female students also reported more severe symptoms and a greater number of emergency room and hospital admissions.     

Allergic rhinitis with or without concomitant asthma: difference in perception of dyspnoea and levels of fractional exhaled nitric oxide

BACKGROUND/AIM: Allergic rhinitis (AR) is a risk factor for developing clinical asthma. Moreover, AR is often associated with bronchial hyper-responsiveness (BHR). The aim of the present study was to investigate whether patients with AR and asthma differed from AR with or without BHR in degree of perception of dyspnoea and airway inflammation, measured as fractionated exhaled nitric oxide (NO). MATERIALS: Twenty-nine patients with seasonal AR (timothy) were investigated with metacholine challenge test. Fourteen healthy non-reactive subjects served as controls. METHODS: (1) Metacholine challenge test, cut-off value forced expiratory volume in 1 s (FEV(1)) PD20 2,000 microg. Slope value for metacholine was calculated as %fall in FEV(1)/mol metacholine. Dyspnoea during challenge was measured with a 10-graded modified Borg score. (2) Measurement of fractional-exhaled nitric oxide (FENO) at flow rate 50 mL/s. RESULTS: Eighteen patients reported AR only, without asthma symptoms, and 12 (67%) were BHR. Eleven subjects had both rhinitis and asthma symptoms. Patients with rhinitis and asthma reported significantly more dyspnoea per percent fall in FEV(1) compared with those with rhinitis and BHR. Moreover, those with rhinitis and asthma had significantly higher NO values compared with those with rhinitis and BHR. CONCLUSION: The difference between rhinitis patients with or without asthma symptoms seems to be mainly a question of perception of dyspnoea. However, FENO measurement indicates that dyspnoea may also be associated with increased inflammatory activity in the peripheral airways.     

Risk factors for wheezing in early adolescence: a prospective birth cohort study in Brazil.

BACKGROUND: Many asthma studies are available in the literature, but few investigated whether risk factors for asthma differ by sex. OBJECTIVE: To evaluate risk factors for wheezing in early adolescence, with emphasis on sex differences. METHODS: A prospective birth cohort study was initiated in 1993; 87.5% of the original cohort was traced at 11 years, totaling 4,452 adolescents. Current wheezing was defined as at least 1 crisis in the previous 12 months. The following independent variables were analyzed: maternal smoking during pregnancy, wheezing at 4 years, maternal wheezing, and adolescent body mass index. RESULTS: Current wheezing affected 13.5% (95% confidence interval [CI], 12.4%-14.5%) of the cohort. The prevalence of current wheezing was 15.3% (95% CI, 13.7%-16.8%) in boys and 11.7% (95% CI, 10.4%-13.1%) in girls (P < .001). Maternal smoking was related to an increased risk of wheezing for boys but not for girls. There was a significant tracking of wheezing from 4 to 11 years in both sexes, although the magnitude was stronger for boys. A dose-response association between maternal wheezing and adolescent wheezing was observed in boys but not in girls. Finally, obesity was associated with an increased risk of wheezing in boys but not in girls. CONCLUSIONS: The variables explored in this investigation had a stronger effect on adolescent wheezing in boys than in girls. Public health strategies aimed at minimizing the burden of wheezing should take these sex differences into account.     

Geographic variations in the effect of atopy on asthma in the European Community Respiratory Health Study

BACKGROUND: Atopy has long been related to asthma. The prevalences of both atopy and asthma have shown substantial variation. OBJECTIVE: We sought to assess geographic variations in the fraction of asthma attributable to IgE sensitization to specific allergens in the European Community Respiratory Health Survey. METHODS: A cross-sectional study was undertaken during the years 1991 and 1992 on 13,558 individuals in 36 centers in 16 countries. Asthma was defined in several ways, variously incorporating reported symptoms, bronchial responsiveness to methacholine, and physician diagnosis. Specific IgE against house dust mite (Dermatophagoides pteronyssinus), cat, timothy grass, Cladosporium herbarum , and a local allergen (birch, Parietaria judaica , or ragweed) were measured. RESULTS: The overall attributable fraction (AF) of asthma symptoms caused by atopy was 30% but varied widely between centers, ranging from 4% to 61%. The overall AF increased to 43% when asthma was based on wheezing and bronchial responsiveness, to 45% with a physician diagnosis of asthma, and to 48% when the patient reported more than 12 attacks in the last year. Between centers, the AF for atopy was significantly correlated with the prevalence of atopy among the asthmatic patients ( r = 0.91) and with the sensitization to house dust mite ( r = 0.64), as well as with the prevalence of asthma among atopic individuals ( r = 0.43) and the prevalence of asthma among nonatopic individuals ( r = -0.51). CONCLUSION: The effect of atopy on the prevalence of asthma varies widely between centers, probably because of variations in factors related to the expression of asthma and to the prevalence of sensitization, particularly to house dust mite.     

Mucosal symptoms elicited by fragrance products in a population-based sample in relation to atopy and bronchial hyper-reactivity

BACKGROUND: Exposure to perfume and fragrance products may, in some individuals, cause symptoms from the eyes and airways. The localization, character and risk factors of such symptoms in the general population are unknown. OBJECTIVE: To investigate both the localization and character of symptoms from the eyes and airways elicited by fragrance products, and the associations between such symptoms and skin prick test reactivity (atopy), methacholine bronchial hyper-reactivity (BHR), allergic rhinitis and asthma. METHODS: A questionnaire on mucosal symptoms elicited by fragrance products was posted to 1189 persons who had participated in a Danish population-based study of allergic diseases in 1997/1998. The study included measurement of BHR, atopy, forced expiratory volume in 1 s (FEV1), and serum eosinophilic cationic protein (serum ECP). RESULTS: The response rate was 79.6%. Symptoms from the eyes or airways elicited by fragrance products were reported by 42%. BHR (adjusted odds ratio 2.3, 95% confidence interval 1.5-3.5) was independently associated with symptoms from the eyes and airways elicited by fragrance products. There were no significant associations between these symptoms and atopy, FEV1 or serum ECP. CONCLUSIONS: Mucosal symptoms from the eyes and airways were common in this population. BHR was a significant and independent predictor of these symptoms. The lack of association with atopy suggested that IgE-mediated allergic mechanisms do not play a major role in the development of these symptoms.