Gaseous air pollution and atopy

BACKGROUND: Photochemical air pollutants are commonly thought to be implicated in the gradual increase in the prevalence of atopy. However, no epidemiological data are available. METHODS: To clarify this issue, we performed a cross-sectional epidemiological survey in 2604 primary school children, 10 and 11 years old, living in seven communities among which some have the highest photochemical exposure in France. The mean levels of the main gaseous air pollutants (SO2, NO2 and O3) were measured during a 2-month period in 1993. The protocol included a standardized questionnaire, skin prick tests to common aeroallergens and in the atopic children, collection of a sample of mattress dust to measure group 1 mite allergens. Atopy was only defined on the basis of the skin prick tests. RESULTS: Percentage of positive skin tests and the number of positive skin tests were similar in the different communities looked at. The distribution of dust samples with a group 1 allergen level greater than 2 microg/g dust, was also similar. Logistic regression analysis including potential confounding factors, as well as the mean level of air pollutants, did not demonstrate any association between atopy and mean SO2, NO2 and O3 levels. CONCLUSION: The increase in photochemical air pollutants is unlikely to be a major determinant for the recent increase in the prevalence of atopy.     

Long-term exposure to background air pollution related to respiratory and allergic health in schoolchildren

BACKGROUND: The impact of air pollution on asthma and allergies still remains a debate. OBJECTIVE: Our cross-sectional study was intended to analyse the associations between long-term exposure to background air pollution and atopic and respiratory outcomes in a large population-based sample of schoolchildren. METHODS: Six thousand six hundred and seventy-two children aged 9-11 years recruited from 108 randomly schools in six French cities underwent a clinical examination including a skin prick test (SPT) to common allergens, exercise-induced bronchial reactivity (EIB) and skin examination for flexural dermatitis. The prevalence of asthma, allergic rhinitis (AR) and atopic dermatitis was assessed by a standardized health questionnaire completed by the parents. Three-year-averaged concentrations of air pollutants (NO2, SO2, PM10 and O3) were calculated at children' schools using measurements of background monitoring stations. RESULTS: After adjusting for confounders, EIB, lifetime asthma and lifetime AR were found to be positively related to an increase in the exposure to SO2, PM10 and O3. The adjusted odds ratios (aOR) per increase of 5 microg/m3 of SO2 was 1.39 (95% confidence interval (CI)=1.15-1.66) for EIB and 1.19 (1.00-1.41) for lifetime asthma. The aOR for lifetime AR per increase of 10 microg/m3 of PM10 was 1.32 (CI=1.04-1.68). Moreover, SPT positivity was associated with O3 (aOR=1.34; CI=1.24-1.46). Associations with past year symptoms were consistent, even if not always statistically significant. Results persisted in long-term resident (current address for at least 8 years) children. However, no consistent positive association was found with NO2. CONCLUSIONS: A moderate increase in long-term exposure to background ambient air pollution was associated with an increased prevalence of respiratory and atopic indicators in children.     

Air pollution and seasonal asthma during the pollen season. A cohort study in Puertollano and Ciudad Real (Spain)

BACKGROUND: Many studies have demonstrated a positive association between air pollutants and emergency visits for asthma. However, few studies have included pollen when analysing this relationship in mild-moderate asthmatic patients. OBJECTIVE: To determine the importance of the pollutants such as ozone (O(3)), particles (PM(10)), nitrogen dioxide (NO(2)) and sulphur dioxide (SO(2)) in the clinical course of mild-moderate pollen-allergic asthmatic patients from two Spanish towns in La Mancha: Puertollano (high pollution levels) and Ciudad Real (low pollution levels). METHODS: We used a Poisson regression model to study a cohort of 137 patients from Puertollano and Ciudad Real during two pollen seasons (2000-2001) and analysed the relationship between air pollutant and pollen levels and daily symptoms, the medication used and peak-flow measurements. RESULTS: The number of asthma symptoms and the mean values of the PM(10), SO(2) and NO(2) levels were higher in Puertollano than in Ciudad Real. In Puertollano, the risk of asthma increased by 6% with a 3-day lag for PM(10), by 8% with a 3-day lag for O(3), by 4% with a 1-day lag for SO(2) and by 15% with a 3-day lag for O(3) when its values exceeded the health threshold (P < 0.05). CONCLUSIONS: The air pollution levels in Puertollano were associated with an increased risk of asthma symptoms in pollen-allergic asthmatic patients com pared with a similar group from Ciudad Real.     

The prevalence of asthma and rhinitis in a Sudanese community seasonally exposed to a potent airborne allergen (the “green nimitti” midge,Cladotanytarsus lewisi)

The period prevalence rates for asthma and rhinitis were studied in a Sudanese village close to the Nile (Kalakla), where the inhabitants are seasonally exposed to very large numbers of nonbiting midges (the “green nimitti” midge, Cladotanytarsus lewisi [Diptera: Chironomidae]). The results were compared with those in a control village some distance from the river, where this midge nuisance does not occur. Of the 5262 persons enumerated in Kalakla, 4.9% suffered from asthma compared with 3.2% of the 2634 in the control area. For allergic rhinitis the rates were 6.7% for Kalakla and 1.5% in the control town. The percentage of patients with the combination of asthma and allergic rhinitis was four times greater in the affected area. These differences were all highly statistically significant. Asthma and rhinitis appeared to affect all occupational classes in both locations with an unexplained high prevalence in civil servants. In both areas the majority with asthma developed their disease by young adulthood, with a predominance in males in almost all age groups. In Kalakla the rates for both asthma and rhinitis increased with age. In the control town there was a similar trend for rhinitis, but the prevalence rates for asthma did not vary appreciably with age. The patient's own subjective assessment of provoking agents and the higher incidence of symptoms during the winter months (the “green nimitti” season) indicated that seasonal exposure to chironomids was a major etiologic factor in asthma and rhinitis in Kalakla. These epidemiologic findings support previous immunologic data which indicated that the “green nimitti” midge is a potent seasonal allergen and that repeated exposure results in a very high incidence of allergic rhinitis as well as a significant increase in the indigenous asthmatic population.     

The relationships between the prevalence of asthmatic symptoms and environmental factors]

The relationships between the prevalence of asthmatic symptoms and environmental factors were evaluated using a modified version of the Japanese ATS-DLD children's questionnaire. The questionnaire was distributed to 13,306 students in 3 areas of Yokohama City; in 1986 (4705), 1988 (4440), and 1991 (4161). The results indicate: 1. The prevalence of asthmatic symptoms among boys increased slightly from 1986 (9.2%) to 1991 (9.6%), but no increase was observed that among girls (5.7%). The overall prevalence among boys was 1.7 times higher than that among girls. 2. On the whole, the air pollution level was Tsurumi-ku > Naka-ku > Midori-ku. But the prevalence of asthmatic symptoms among boys was Naka-ku > Tsurumi-ku > Midori-ku in 1986, 1988 and 1991. The prevalence among girls was the same result in 1986, but in 1988 and 1991, it was Tsurumi-ku > Naka-ku > Midori-ku. 3. In the longitudinal study of the same group, the prevalence of asthmatic symptoms among boys decreased between 5th and 6th grade. In contrast, remission of asthma increased between 5th and 6th grade. And the prevalence of asthmatic symptoms among girls decreased between 3rd and 6th grade. In contrast, remission of asthma increased between 3rd and 6th grade. 4. Children who had a personal or family history of allergic diseases, allergic disposition, respiratory diseases before 2 years old, wheezing or difficulty in breathing, or allergies against foods or medicines, showed a statistically significant Odds ratio (p < 0.01) for asthmatic symptoms.     

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.     

Specific IgG1 and IgG4 antibodies to citrus red mite in citrus farmers: a study of their relationship to respiratory symptoms

Citrus red mite (CRM) is known as the most common sensitizing allergen in subjects with asthma and rhinitis working on citrus farms. The aim of this study is to evaluate the role of specific IgG1 (slgG1) and specific IgG4 (slgG4) to CRM in citrus farmers. Questionnaire survey and skin prick test including CRM antigen was done by 136 workers. Specific IgE (slgE), slgG1 and slgG4 to CRM were detected by enzyme-linked immunosorbent assay (ELISA). CRM-sensitive-asthma was diagnosed upon presence of asthmatic symptoms by questionnaire, airway hyperresponsiveness to methacholine and slgE to CRM. CRM-sensitive rhinitis was diagnosed upon presence of rhinitis symptoms and slgE to CRM. Eleven (8.1%) had CRM-sensitive asthma and 25 (18.4%) had CRM-sensitive rhinitis. Significant association was noted between presence of asthmatic symptoms and slgE or slgG4 (p<0.05, respectively), while no significant association was noted in slgG1 (p>0.05). Significant association was noted in the prevalence between slgG4 and slgE (p<0.05), while no significant association was noted between slgG1 and slgG4 or slgE (p<0.05, respectively). There was a significant correlation between slgE and slgG4 level (r=0.39, p<0.05). These findings suggest that the presence of slgG1 to CRM is response to CRM exposure, and further studies will be needed to evaluate the role of slgG4.     

Pollen counts in relation to the prevalence of allergic rhinoconjunctivitis, asthma and atopic eczema in the International Study of Asthma and Allergies in Childhood (ISAAC)

BACKGROUND: Although pollens are major allergens associated with allergic rhinoconjunctivitis and asthma, there is little information about the relative prevalence of these conditions in populations with different pollen exposures. OBJECTIVE: The purpose of this study was to investigate the relationship between pollen exposure and allergic symptoms among children in different countries. METHODS: An ecological analysis was conducted to see whether pollen exposure (pollen counts, and duration and severity of pollen seasons) is associated with symptoms of allergic rhinoconjunctivitis, asthma and atopic eczema in 28 centres within 11 countries (nine being in Europe). Data on the prevalence of symptoms in 13-14-year olds were based on the responses to the written questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC). The analysis was adjusted for gross national product and mean annual relative humidity. RESULTS: There was little relationship between pollen exposure and symptom prevalence, except for a significant inverse association between grass pollen counts and lifetime prevalence of the symptoms of allergic rhinitis (P=0.03). Almost all the regression coefficients were negative. The associations were even weaker and all non-significant when the analyses were conducted within countries, using a random intercept fixed slope model, but there was still no evidence of a positive association between pollen exposure and symptoms. CONCLUSION: There is a weak but consistent tendency for the prevalence of allergic symptoms to be inversely associated with pollen exposure. This finding accords with evidence from several countries, suggesting that the prevalence of hayfever and asthma tends to be lower in rural than in urban areas, and lowest among people living on farms. Exposure to allergenic pollen in early life does not appear to increase the risk of acquiring symptoms of respiratory allergy, and may even give some protection against them.     

Occupational asthma and rhinitis related to laboratory rats: serum IgG and IgE antibodies to the rat urinary allergen

Allergic reactions to rat urinary proteins are an important cause of occupational asthma and rhinitis among laboratory workers. We have measured IgG and IgE antibodies to a purified rat urinary allergen in sera from 179 laboratory workers of whom 30 reported symptoms on exposure to rats. There was a very good correlation between IgE antibodies and positive skin tests. In addition, there was a close correlation between reported asthmatic reactions and serum IgE antibody to rat allergen: IgE ab was present in 12/18 of workers with asthmatic reactions but in only 2/135 of workers without symptoms (p less than 0.001). Serum IgG antibodies to rat allergen were present in all sera with IgE antibody but were also present in 30% of asymptomatic individuals. The incidence and quantity of IgG antibody correlated with the degree of exposure to animals (i.e., hours per day) but not with the length of exposure in years. Our results on rat allergy confirm that there is an increased incidence of asthma among individuals who were atopic as judged by positive skin tests to other allergens. However, this relationship did not apply to individuals with rhinitis alone, and excluding atopic individuals from employment would have been a very inefficient method of reducing asthma or rhinitis in this group. Our results confirm that IgE antibody responses to rat urinary allergen are an important cause of occupational disease. The results for IgG antibody suggest that their prevalence represents a marker for the degree of exposure to rat proteins.     

Association of allergic symptoms in children with those in their parents

This study investigated the association of asthma, allergic rhinitis, and eczema in United Arab Emirates (UAE) schoolchildren with allergic conditions in their parents. A cross-sectional, population-based study among schoolchildren aged 6–14 years was conducted in Al-Ain City, UAE. The field survey was conducted from October 1992 to May 1993. A questionnaire was distributed to 850 UAE government school students from representative, randomly selected schools with a majority of UAE nationals. The student and both or either of the parents were present during the interview. A detailed clinical history of asthma and wheezing in the target children and a history of asthma and allergic rhinitis in their parents and siblings were obtained. It was found that 13.1% of asthmatic children had mothers with asthma (relative risk (RR) = 2.67; 95% confidence intervals (CI)= 1.65–4.35), and 15.2% had fathers who were asthmatic (RR = 2.85; 95% CI = 1.81–4.49). This contrasted with 4.4% of nonasthmatic children who had fathers with asthma, and 4.1% who had mothers with asthma. A similar pattern was seen with symptoms of allergic rhinitis when it was found that 34.3% of children who had asthma had mothers with allergic rhinitis (RR: 2.74; 95% CI: 1.90–3.94). The corresponding figure for fathers was 12.7% (RR: 0.92; 95% CI: 0.5–1.7). The frequency of either parent of the asthmatic children having allergic rhinitis was 28.6%; for both parents, it was 14.5%. It was also found that asthmatic children had 12.5% of their fathers, 32.8% of their mothers, 26.4% of either of their parents, and 33.3% of both their parents suffering from allergic rhinitis. Siblings of the asthmatic children were also studied to establish the relationship between allergic conditions in the siblings and asthma in the study sample. It was found that in the asthmatic study population the frequency of siblings having asthma was 31.9%; of those having allergic rhinitis, 21.3%; and of those having eczema, 16.1%. Twenty-nine percent of either of the parents of the children with eczema had the same condition, and the corresponding figure for allergic rhinitis was 36.5%. The prevalence rate of asthma in the schoolchildren studied increased dramatically to 22% when wheeze, asthma, or nocturnal cough were grouped together. When eczema and allergic rhinitis were also considered together along with the above, the rate increased to 31%. The size of the family did not seem to affect the parent/child association of allergic symptoms. Our findings indicate that there is a strong association between respiratory allergies and eczema in parents and in their asthmatic children, thereby indicating a strong genetic basis for the occurrence of asthma in particular and atopy in general.     

Prevalence and severity of allergic rhinitis in house dust mite-allergic patients with bronchial asthma or atopic dermatitis

BACKGROUND: Allergic rhinitis, asthma and atopic dermatitis are closely associated. Although population-based studies report a high prevalence of rhinitis among asthma patients, less is known of the association between rhinitis and atopic dermatitis and the severity of concomitant rhinitis. OBJECTIVES: We aimed to determine the prevalence and severity of allergic rhinitis among asthmatics and patients with atopic dermatitis and assessed whether age and comorbidity influence the severity of rhinitis signs and symptoms. METHODS: Three hundred and twenty-five patients recruited for a multicentre trial to study the effect of encasings of mattresses, pillows and duvets on signs and symptoms of allergic rhinitis and/or asthma and/or atopic dermatitis recorded visual analogue scores (VAS) and daily symptom scores and underwent nasal challenge tests with house dust mite (HDM). RESULTS: Based on history and clinical symptoms 92% of the 164 asthmatic patients and 85% of the 86 patients with atopic dermatitis could be diagnosed as having rhinitis. Inclusion of a positive provocation to HDM did not result in a substantial lower prevalence of rhinitis. Subjects reported moderate symptoms, with mean rhinitis VAS scores ranging from 40.0 to 55.0. Presence of atopic dermatitis was associated with lower rhinitis VAS and symptoms scores, whereas in multivariate analysis the presence of asthma was positively associated with nasal responsiveness to HDM. CONCLUSION: The prevalence of nasal symptoms in patients with bronchial asthma or atopic dermatitis and sensitized to house dust mites is high. Although the majority of patients experience mild to moderate symptoms, the presence of nasal disease needs to be examined in all patients with atopic disorders.     

Dietary factors associated with physician-diagnosed asthma and allergic rhinitis in teenagers: analyses of the first Nutrition and Health Survey in Taiwan

The occurrence of asthma and allergy are related to lifestyle factors, and dietary pattern may be one of the contributing factors. To examine the possible association between dietary intake and the prevalence of asthma and allergic rhinitis in teenagers. In a population-based cross-sectional survey, the relationship was sought between food frequency and physician-diagnosed asthma and allergic rhinitis in 1166 adolescents aged 13-17. The prevalence was 4.0% for asthma and 12.4% for rhinitis. Living in an urbanized area was a significant predictor of asthma and rhinitis. In univariate analysis, higher frequencies of oily fish, butcher's meat, liver and deep-fried foods were associated with asthma. Relevant food frequency variables were dichotomized at the 75th percentile for multivariate logistic regression analysis, which included adjustment for two levels of urbanization. Asthma was associated with intakes of liver (OR = 2.32, 95%CI 1.11-4.80), deep-fried foods (OR = 2.13, 95%CI 1.06-4.30) and butcher's meat (OR 1.84, 95%CI 0.89-3.80). In a similar analysis, allergic rhinitis was associated with liver (OR = 1.67, 95%CI 1.06-2.63). No protective effect was demonstrated for any of the food items examined. Protein-rich and fat-rich foods of animal origin were associated with a higher prevalence of asthma in teenagers.     

Similar levels of nitric oxide in exhaled air in non-asthmatic rhinitis and asthma after bronchial allergen challenge

BACKGROUND: Nitric oxide in exhaled air (eNO) is elevated in allergic asthma compared with healthy subjects and has been proposed as a marker of bronchial inflammation. However, eNO is elevated to a lesser extent in allergic non-asthmatic rhinitis as well. Considering the distinctive clinical appearances of both allergic diseases, differences in eNO are expected to persist after allergen exposure. The aim of the study was to compare allergen-induced changes in eNO in house dust mite sensitized patients with asthma and patients with perennial rhinitis without asthma symptoms. METHODS: Bronchial allergen challenge was performed in 52 patients sensitized to house dust mite (Dermatophagoides pteronyssinus), of whom 26 had non-asthmatic rhinitis and 26 had asthma. Levels of eNO were measured before and 1 h, 1 day and 1 week after challenge. RESULTS: At baseline eNO was significantly lower in non-asthmatic rhinitis compared with asthma (geometric mean eNO (SEM): 121 (1.1) in non-asthmatic rhinitis vs 197 (1.1) nl/min in asthma, P < 0.006). However, the increase in eNO after bronchial allergen challenge in non-asthmatic rhinitis, in particular in those patients with a dual asthmatic response, significantly exceeded the increase in asthma resulting in similar levels of eNO after challenge (geometric mean eNO (SEM) at 24 h postchallenge 204 (1.1) in non-asthmatic rhinitis vs 244 (1.1)nl/min in asthma, P = 0.3). CONCLUSION: The difference in eNO between non-asthmatic rhinitis and asthma at baseline is abolished after allergen exposure due to a significantly greater increase in eNO in non-asthmatic rhinitis.     

Association between body mass index and allergy in teenage girls in Taiwan

BACKGROUND: The prevalence of atopy and asthma is affected by age, sex and lifestyle factors. Obesity was reported to be a risk factor for asthmatic symptoms in children and adults. OBJECTIVE: To examine the relation between body mass index (BMI) and the prevalence of atopy, rhinitis, wheezing and bronchial responsiveness in adolescents. METHODS: BMI (kg/m2), skin-prick test, bronchial hyperresponsiveness (BHR) to methacholine, and self-reported rhinitis and airway symptoms were assessed in a cross-sectional survey in 1459 eighth-grade students (age 13.2 to 15.5, mean 13.6 years) of seven junior high schools in northern Taiwan. RESULTS: The prevalence of atopy was 42% in boys and 27% in girls. The study population was grouped into quintiles of BMI by sex. Girls in the highest BMI quintile had higher prevalence of atopy and rhinitis symptoms. Compared with the middle three quintiles, they had increased risk of atopy in multivariate analyses adjusted for area of living, sibling number, parent education level and family history of asthma (odds ratio = 1.77, 95% confidence interval = 1.15-2.73). Girls with the lowest BMI quintile had lower prevalence of BHR and wheezing. Compared with the middle three quintiles, they had reduced risk of BHR in multivariate analyses adjusted for area of living, atopy, family history of asthma, and baseline pulmonary function (odds ratio = 0.40, 95% confidence interval = 0.20-0.81). No association between BMI and atopy or BHR was seen in boys. CONCLUSION: BMI was a significant predictor of atopy, allergic symptoms and BHR in teenage girls.     

Effects of air pollution on asthma hospitalization rates in different age groups in Hong Kong

AIMS: To assess the relationship between levels of ambient air pollutants and hospitalization rates for asthma in Hong Kong (HK). METHODS: This is a retrospective ecological study. Data of daily emergency hospital admissions to 15 major hospitals in HK for asthma and indices of air pollutants [sulphur dioxide (SO(2)), nitrogen dioxide (NO(2)), ozone (O(3)), particulates with an aerodynamic diameter of <10 microm particulate matter (PM(10)) and 2.5 microm (PM(2.5))] and meteorological variables from January 2000 to December 2005 were obtained from several government departments. Analysis was performed by the generalized additive models with Poisson distribution. The effects of time trend, season, other cyclical factors, temperature and humidity were adjusted. Autocorrelation and overdispersion were corrected. RESULTS: Altogether, 69 716 admissions were assessed. Significant associations were found between hospital admissions for asthma and levels of NO(2), O(3), PM(10) and PM(2.5). The relative risks (RR) for hospitalization for every 10 microg/m(3) increase in NO(2), O(3), PM(10) and PM(2.5) were 1.028, 1.034, 1.019 and 1.021, respectively, at a lag day that ranged from cumulative lag 0-4 to 0-5. In a multi-pollutant model, O(3) was significantly associated with increased admissions for asthma. The younger age group (0-14 years) tended to have a higher RR for each 10 microg/m(3) increase in pollutants than those aged 15-65 years. The elderly (aged >/=65 years) had a shorter 'best' lag time to develop asthma exacerbation following exposure to pollutants than those aged <65 years. CONCLUSION: Adverse effects of ambient concentrations of air pollutants on hospitalization rates for asthma are evident. Measures to improve air quality in HK are urgently needed.     

Correlation between nasal symptoms and asthma severity in patients with atopic and nonatopic asthma.

BACKGROUND: The association between allergic rhinitis and asthma has been well recognized, and it has been postulated that rhinitis may worsen asthma. OBJECTIVE: To investigate the severity of asthma among patients with atopic and nonatopic asthma with and without nasal symptoms. METHODS: Atopic asthmatic patients and nonatopic asthmatic patients were identified from the records of a university-based asthma clinic. A comparison of demographic clinical features was made within and between these 2 asthmatic groups, dichotomized according to the presence or absence of rhinitis. RESULTS: A total of 178 patients were classified as having atopic asthma and 218 as having nonatopic asthma. The atopic asthmatic patients with nasal symptoms compared with those without had a higher mean forced expiratory volume in 1 second (FEV1), a higher forced vital capacity (FVC), and a higher FEV1/FVC ratio, used fewer oral steroids, and had fewer hospitalizations. The nonatopic asthmatic patients with nasal symptoms compared with those without used more inhaled steroids (and they were also more likely to have nasal polyps on examination). Atopic, relative to nonatopic, asthmatic patients were younger, had a longer duration of asthma, had a higher FEV1/FVC ratio, and took fewer oral steroids. CONCLUSION: Contrary to current hypotheses, in this study the severity of asthma among atopic asthmatic patients was less in those with nasal symptoms. Conversely, among the nonatopic asthmatic patients, asthma was more severe among those with nasal symptoms than those without nasal symptoms.     

Temporal relationship between air pollution and hospital admissions for asthmatic children in Hong Kong

BACKGROUND: Many epidemiological studies have shown positive association between respiratory health and current levels of outdoor air pollution in Europe and America. OBJECTIVE: The aim of this study was to investigate the association between air pollution and the number of childhood admissions for asthma in Hong Kong. METHODS: Daily counts of childhood admission for asthma to a large teaching Hospital were obtained from the computerized database for the period 1993-1994. A Poisson regression allowing for seasonal patterns and meteorological conditions was used to assess the associations between the number of Hospital admissions and the three pollutants: nitrogen dioxide, sulphur dioxide and inhalable particles (measured as PM10, particles < 10 microm in aerodynamic diameter). RESULTS: A total of 1217 children under 15 years of age were admitted for asthma during the study period. The calculated annual hospitalization rates were 283 and 178 per 100 000 for boys and girls, respectively. The mean PM10, NO2 and SO2 levels were 44.1 microg/m3, 43.3 microg/m3, and 12.2 microg/m3, respectively. Daily admission for asthma increased significantly with increasing ambient level of nitrogen dioxide (relative risk (RR) = 1.08 per 10 microg/m3 increase), sulphur dioxide (RR = 1.06) and inhalable particles (RR = 1.03). No association was found between hospital admission and humidity, temperature or atmospheric pressure. CONCLUSION: This is the first daily time series study of childhood admissions for asthma and air pollution in Hong Kong. The results support that current levels of air pollution contribute to the respiratory morbidity in asthmatic children in Hong Kong.     

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.     

Frequency and intensity of late asthmatic reactions after bronchial allergen challenge in asthma and rhinitis

The occurrence of late asthmatic reactions after bronchial allergen challenge was studied in 50 house dust mite allergic patients subdivided in three groups: one group had asthma without nasal symptoms, another group had rhinitis without pulmonary symptoms and a third group had a combination of both asthma and rhinitis. Late asthmatic reactions were present in 80% of asthmatic patients and in 18.7% of rhinitis patients. The degree of non-specific bronchial reactivity to histamine (provocative dose 15 or PD15 histamine) and the degree of immediate reactivity to allergen (PD15 house dust mite) did not differ significantly between patients with and without late asthmatic reactions. These findings suggest that an important difference between asthma and rhinitis is the lack of late asthmatic reactions in rhinitis patients, whereas the degree of immediate bronchial reactivity to the allergen is similar in asthma and rhinitis.     

Geographical variations of asthma and asthma symptoms among schoolchildren aged 5 to 8 years and 12 to 15 years in Palestine: the International Study of Asthma and Allergies in Childhood (ISAAC).

BACKGROUND: Many studies demonstrated the existence of geographic differences, within and between countries, in the prevalence of asthma, rhinitis, and eczema. However, in Palestine, there are no comprehensive Palestinian data to compare with those from other regional and international centers. OBJECTIVE: To describe the prevalence of asthma and asthma symptoms in schoolchildren in two districts (Ramallah and North Gaza) in Palestine. METHODS: After a two-stage stratified systematic sampling, approximately 14,500 schoolchildren, from the first and second grades of elementary school (ages 5 to 8 years) and eighth and ninth school grades (ages 12 to 15 years), were invited to participate in a survey using International Study of Asthma and Allergies in Childhood phase III questionnaires and protocols. RESULTS: In general, younger children were reported to have a higher 12-month wheezing prevalence rate than older children (9.6 and 7.2%, respectively), and more physician-diagnosed asthma (8.4 and 5.9%, respectively). However, nocturnal cough and exercise-related wheezing were higher in the older age group compared with younger children. Younger children living in North Gaza district showed slightly higher prevalence rates for asthma and asthma symptoms, but older children had higher rates in Ramallah district. After adjustment using logistic regression analysis, male sex, living in inland areas, and younger age were shown to predict 12-month wheezing and physician-diagnosed asthma. CONCLUSIONS: Palestinian children have asthma symptoms rates that are similar to several countries in the Mediterranean region such as Spain and Turkey, but still lower than other Middle East countries such as Saudi Arabia and Israel.