Association of indoor nitrogen dioxide exposure with respiratory symptoms in children with asthma

RATIONALE: Chronic exposure to indoor nitrogen dioxide (NO2) is a public health concern. Over half of U.S. households have a source of NO2, and experimental data suggest potential for adverse respiratory effects. OBJECTIVE: To examine associations of indoor NO2 exposure with respiratory symptoms among children with asthma. METHODS: NO2 was measured using Palmes tubes, and respiratory symptoms in the month before sampling were collected during home interviews of mothers of 728 children with active asthma. All were younger than 12 yr, lived at the sampled home for at least 2 mo, and had asthma symptoms or used maintenance medication within the previous year. MEASUREMENTS: Respiratory symptoms (wheeze, persistent cough, shortness of breath, chest tightness). RESULTS: Mean (SD) NO2 was 8.6 (9.1) ppb in homes with electric ranges and 25.9 (18.1) ppb in homes with gas stoves. In models stratified by housing type (a factor associated with socioeconomic status), gas stove presence and elevated NO2 were each significantly associated with respiratory symptoms, controlling for age, ethnicity, medication, mold/mildew, water leaks, and season of sampling. Among children in multifamily housing, exposure to gas stoves increased likelihood of wheeze (odds ratio [OR], 2.27; 95% confidence interval [95% CI], 1.15, 4.47), shortness of breath (OR, 2.33; 95% CI, 1.12, 5.06), and chest tightness (OR, 4.34; 95% CI, 1.76, 10.69), whereas each 20-ppb increase in NO2 increased both likelihood of any wheeze (OR, 1.52; 95% CI, 1.04, 2.21) or chest tightness (OR, 1.61; 95% CI, 1.04, 2.49), and days of wheeze (rate ratio (RR), 1.33; 95% CI, 1.05, 1.68) or chest tightness (RR, 1.51; 95% CI, 1.18, 1.91). CONCLUSION: Exposure to indoor NO2 at levels well below the Environmental Protection Agency outdoor standard (53 ppb) is associated with respiratory symptoms among children with asthma in multifamily housing.     

Health effects of daily indoor nitrogen dioxide exposure in people with asthma.

Household gas appliances produce nitrogen dioxide (NO2), which may be associated with an increase in symptoms in asthmatics. The relationship between indoor NO2 exposure, and respiratory symptoms in people with asthma was evaluated. Self-reported asthmatics (n=125) wore lapel badges that measured NO2 daily over 6 weeks at home. Outdoor pollutants, spores and meteorological parameters were measured daily, in addition to smoking status and demographic factors. Seven asthma symptoms were recorded in diaries, for analysis by same day and also with 1 day lag exposures, using a generalized estimating equation. Significant interactions were demonstrated between NO2 at age < or =14 yrs, with respect to the symptoms of chest tightness on the same day (odds ratio (OR): 1.29, 95% confidence interval (CI): 1.16-1.43) and with a 1 day lag (OR: 1.29, 95% CI: 1.14-1.46), breathlessness on exertion with a 1 day lag (OR: 1.13, 95% CI: 1.00-1.28), daytime asthma attacks on the same day (OR: 1.13, 95% CI: 1.02-1.26) night asthma attacks on the same day (OR: 1.16, 95% CI:1.03-1.30) and with a 1 day lag (OR: 1.15, 95% CI; 1.03-1.29) after adjustment for potential confounders. A significant interaction between NO2 and age 35-49 yrs was demonstrated for coughs with a 1 day lag (OR: 1.15, 95% CI: 1.01-1.31). Daily personal exposures to NO2 are associated with asthmatic symptoms in children.     

Traffic-related air pollution and respiratory health during the first 2 yrs of life.

As part of an international collaborative study on the impact of Traffic-Related Air Pollution on Childhood Asthma (TRAPCA), the health effects associated with long-term exposure to particles with a 50% cut-off aerodynamic diameter of 2.5 microm (PM2.5), PM2.5 absorbance, and nitrogen dioxide (NO2) were analysed. The German part of the TRAPCA study used data from subpopulations of two ongoing birth cohort studies (German Infant Nutrition Intervention Programme (GINI) and Influences of Lifestyle Related Factors on the Human Immune System and Development of Allergies in Children (LISA)) based in the city of Munich. Geographic information systems (GIS)-based exposure modelling was used to estimate traffic-related air pollutants at the birth addresses of 1,756 infants. Logistic regression was used to analyse possible health effects and potential confounding factors were adjusted for. The ranges in estimated exposures to PM2.5, PM2.5 absorbance, and NO2 were 11.9-21.9 microg m(-3), 1.38-4.39 x 10(-5) m(-1), and 19.5-66.9 microg x m3, respectively. Significant associations between these pollutants and cough without infection (odds ratio (OR) (95% confidence interval (CI)): 1.34 (1.11-1.61), 1.32 (1.10-1.59), and 1.40 (1.12-1.75), respectively) and dry cough at night (OR (95% CI): 1.31 (1.07-1.60), 1.27 (1.04-1.55), and 1.36 (1.07-1.74), respectively) in the first year of life were found. In the second year of life, these effects were attenuated. There was some indication of an association between traffic-related air pollution and symptoms of cough. Due to the very young age of the infants, it was too early to draw definitive conclusions from this for the development of asthma.     

The effect of air pollution on inner-city children with asthma.

The effect of daily ambient air pollution was examined within a cohort of 846 asthmatic children residing in eight urban areas of the USA, using data from the National Cooperative Inner-City Asthma Study. Daily air pollution concentrations were extracted from the Aerometric Information Retrieval System database from the Environment Protection Agency in the USA. Mixed linear models and generalized estimating equation models were used to evaluate the effects of several air pollutants (ozone, sulphur dioxide (SO2), nitrogen dioxide (NO2) and particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) on peak expiratory flow rate (PEFR) and symptoms in 846 children with a history of asthma (ages 4-9 yrs). None of the pollutants were associated with evening PEFR or symptom reports. Only ozone was associated with declines in morning % PEFR (0.59% decline (95% confidence interval (CI) 0.13-1.05%) per interquartile range (IQR) increase in 5-day average ozone). In single pollutant models, each pollutant was associated with an increased incidence of morning symptoms: (odds ratio (OR)=1.16 (95% CI 1.02-1.30) per IQR increase in 4-day average ozone, OR=1.32 (95% CI 1.03-1.70) per IQR increase in 2-day average SO2, OR=1.48 (95% CI 1.02-2.16) per IQR increase in 6-day average NO2 and OR=1.26 (95% CI 1.0-1.59) per IQR increase in 2-day average PM10. This longitudinal analysis supports previous time-series findings that at levels below current USA air-quality standards, summer-air pollution is significantly related to symptoms and decreased pulmonary function among children with asthma.     

Urban air pollution and asthma in children

This study investigated the relationship between atmospheric pollution and emergency hospital admission for asthma among children resident in Turin in the period 1997-1999, using a case-control design. On the basis of the primary diagnosis, pediatric patients (< 15 years old) resident in Turin and admitted for asthma were defined as cases (n(1) = 1,060); age-matched patients admitted for causes other than respiratory diseases or heart diseases were defined as controls (n(2) = 25,523). Nitrogen dioxide (NO(2) in microg/m(3)) and total suspended particulates (TSP in microg/m(3)) were considered as indicators of urban air pollution; sex and age of patient, seasonality, temperature, humidity, solar radiation, and day of admission were considered as principal confounders. Statistical analyses were performed using simple and multiple logistic regression models; the association between emergency admission for asthma and exposure was shown as percentage of risk modification for a 10 microg/m(3) increment of exposure to each pollutant and relative 95% confidence interval. The number of emergency admissions for respiratory causes rose significantly with increased exposure to each pollutant: 2.8% (95% CI, 0.7-4.9%) and 1.8% (95% CI, 0.3-3.2) for a 10 microg/m(3) increment of exposure to NO(2) and TSP, respectively. A significant association was found between increased number of hospital emergency admissions for respiratory causes and exposure to principal urban pollutants in Turin. The study confirms the results reported for other Italian and European cities, using a case-control design.     

Exhaled nitric oxide as a diagnostic test for asthma in rhinitic patients with asthmatic symptoms

BACKGROUND: Rhinitis is a major risk factor for asthma, so that evaluation of the lower airways is recommended in patients with rhinitis. Exhaled nitric oxide (FE(NO)) is considered a marker of airway inflammation and it has been found to be useful for the screening of patients with suspected diagnosis of asthma. Our aim was to assess the validity and accuracy of FE(NO) to identify patients with asthma in 48 non-smoking patients with persistent rhinitis and asthma-like symptoms. METHODS: Asthma was diagnosed on the basis of 12% improvement in FEV1 after salbutamol or a methocholine PD(20)FEV1<800 microg. Prior to lung function FE(NO) was measured with the single exhalation method at 50 ml/s. RESULTS: The geometric mean (95% confidence interval) FE(NO) was significantly higher in the 18/48 asthmatics than in the non-asthmatic patients (60 ppb, CI 95%: 50-89, versus 30 ppb, CI 95%: 28-45, P=0.001). Receiver operating characteristic (ROC) curve for the diagnosis of asthma indicated that FE(NO) is an acceptable discriminator between patients with and without asthma (area under the ROC curve=0.78). None of the asthmatic patients had FE(NO) values<25 ppb and all the patients with FE(NO)>100 ppb (n=5) were asthmatics. The sensitivity and specificity of FE(NO) for detecting asthma, using 36 ppb as cut-off point, were 78% and 60% and the positive and negative predictive values were 54% and 82%, respectively. CONCLUSIONS: Measuring FE(NO) may be useful for the screening of rhinitic patients with asthma-like symptoms.     

Breastfeeding and Asthma Among Brazilian Children

We examined the association of breastfeeding and the presence of chronic respiratory symptoms among 5182 Brazilian schoolchildren 7-14 years of age who were participants in the International Study on Asthma and Allergies in Childhood (ISAAC). The prevalence of medically diagnosed asthma and current wheeze were respectively 4.6% (95% confidence interval [CI] 4.0%-5.2%) and 11.9% (95% CI 11.0%-12.8%). Ninety percent of the mothers in our study population had breastfed their child. After adjusting for potential confounding factors, we found that children who had not been breastfed were more likely to have a medical diagnosis of asthma (odds ration [OR] = 1.51, 95% CI 1.00-2.51), experience current wheeze (OR = 1.29, 95% CI 0.96-1.74), and wheeze after exercise (OR = 1.51, 95% CI 1.01-2.27) than children who had been breastfed for more than 6 months. This effect was only present among children with no family history of asthma (OR = 1.54, 95% CI 0.90-2.42 for medical diagnosis of asthma; OR = 1.27, 95% CI 0.93-1.75 for current wheezing; and OR = 1.74, 95% CI 1.12-2.6 for wheeze after exercise). We conclude that the low prevalence of asthma and wheeze observed in our population may be partly related to the high level of breastfeeding.     

Effect of ambient air pollution on pulmonary exacerbations and lung function in cystic fibrosis

Information concerning the impact of environmental factors on cystic fibrosis (CF) is limited. We conducted a cohort study to assess the impact of air pollutants in CF. The study included patients over the age of 6 years enrolled in the Cystic Fibrosis Foundation National Patient Registry in 1999 and 2000. Exposure was assessed by linking air pollution values from the Aerometric Information Retrieval System with the patients' home zip code. After adjusting for confounders, a 10 microg/m(3) rise in particulate matter (both with a median aerodynamic diameter of 10 microm (PM(10)) or less and with an aerodynamic diameter of 2.5 microm or less (PM(2.5)) was associated with an 8% (95% confidence interval [CI], 2-15%) and 21% (95% CI, 7-33%) increase in the odds of two or more exacerbations, respectively; a 10-ppb rise in ozone was associated with a 10% (95% CI, 3-17%) increase in odds of two or more exacerbations. For every increase in PM(2.5) of 10 microg/m(3), there was an associated fall in FEV(1) of 24 ml (7-40) (95% CI) after adjusting for confounders. PM(2.5)'s association with mortality did not achieve statistical significance (adjusted RR = 1.32 per 10 microg/m(3) 0.91-1.93; 95% CI). Annual average exposures to particulate air pollution was associated with an increased risk of pulmonary exacerbations and a decline in lung function, suggesting a role of environmental exposures on prognosis in CF.     

Asthma in children exposed to nitrogen dioxide in ice arenas.

Very high concentrations of nitrogen dioxide (NO2) have been measured in arenas using combustion engine-powered resurfacing machines. This study was performed to compare the occurrence of asthma in children playing ice hockey in arenas using propane-powered machines and in children attending arenas using electric machines. Children regularly playing hockey in the arenas (nine propane, six electric) were sent a questionnaire, including questions on allergic disease and risk factors. Measurements of NO2 were performed with passive diffusion samplers during 3 consecutive days. The mean NO2 concentration in the propane arenas was 276 microg x m(-3) (range 28-1015 microg x m(-3)) and 11 microg x m(-3) (2-30) in the electric arenas. Questionnaires were answered by 1,536 children (78%), with an overall prevalence of asthma of 16%. The odds ratio (OR) for asthma was 0.9 (95% confidence interval (CI) 0.7-1.2) comparing propane arenas to electric. However, children in propane arenas with higher than median concentration of NO2 reported more wheezing (OR 1.4, 95% CI 1.0-1.9) and nasal symptoms (OR 1.7, 95% CI 1.3-2.3) than children in propane arenas with lower concentrations. In conclusion, children playing ice hockey in indoor arenas have a high prevalence of asthma, but it appears unlikely that increased exposure to combustion products, including nitrogen dioxide, is a major contributor to this excess risk.     

Association between daily ambient air pollution and respiratory symptoms in children with asthma and healthy children in western Japan

Objective: In recent years, air pollutant concentrations in Japan have decreased slightly; however, there are growing concerns about the influences of transnational air pollution on respiratory illness. We aimed to clarify the short-term association between the ambient air pollution and respiratory symptoms among children without asthma, children with asthma not using long-term medications (CA-nonLTM), and those using them (CA-LTM). Methods: A total of 138 children attending 2 primary schools and 71 children with asthma regularly visiting cooperating medical institutions were recruited. Study participants measured peak expiratory flow (PEF) twice a day and recorded coughing, nasal symptoms, and medication use in a diary. Predicted associations between daily air pollutant concentrations and respiratory symptoms, and PEF were evaluated using case-crossover and generalized estimate equation models. Results: Changes in %maxPEF per 10 ppb oxidant (Ox) increase in children without asthma, CA-nonLTM, and CA-LTM were ?0.26% (95% CI: ?0.49, ?0.03), ?0.51% (95% CI: ?0.89, ?0.12), and ?0.20% (95% CI: ?0.42, 0.01), respectively. The odds ratios for coughing per 10 ppb Ox increase in the Lag0 model were 1.34 (95% CI: 1.11, 1.60), 1.52 (95% CI: 1.12, 2.07), and 1.06 (95% CI: 0.93, 1.20), respectively. These suggested that the Ox concentration has graded effects on %maxPEF and coughing, in the following descending order, CA-nonLTM, children without asthma, and CA-LTM. The Ox concentration was also positively associated with nasal symptoms in children without asthma and CA-LTM. Conclusion: Our results suggest that using long-term medications to manage asthma may play an important role in preventing exacerbation of respiratory symptoms due to air pollution.     

A study of twelve Southern California communities with differing levels and types of air pollution. I. Prevalence of respiratory morbidity

To study possible chronic respiratory effects of air pollutants, we initiated a 10-yr prospective cohort study of Southern California children, with a study design focused on four pollutants: ozone, particulate matter, acids, and nitrogen dioxide (NO2). Twelve demographically similar communities were selected on the basis of historic monitoring information to represent extremes of exposure to one or more pollutants. In each community, about 150 public school students in grade 4, 75 in grade 7, and 75 in grade 10 were enrolled through their classrooms. Informed consent and written responses to surveys about students' lifetime residential histories, historic and current health status, residential characteristics, and physical activity were obtained with the help of the parents. In the first testing season, 3,676 students returned questionnaires. We confirmed associations previously reported between respiratory morbidity prevalence and the presence of personal, demographic, and residential risk factors. Rates of respiratory illness were higher for males, those living in houses with pets, pests, mildew, and water damage, those whose parents had asthma, and those living in houses with smokers. Wheeze prevalence was positively associated with levels of both acid (odds ratio [OR] = 1.45; 95% confidence interval [CI], 1.14-1.83) and NO2 (OR = 1.54; 95% CI, 1.08-2.19) in boys. We conclude, based on this cross-sectional assessment of questionnaire responses, that current levels of ambient air pollution in Southern California may be associated with effects on schoolchildren's respiratory morbidity as assessed by questionnaire.     

PM10, and children's respiratory symptoms and lung function in the PATY study

Studies of the impact of long-term exposure to outdoor air pollution on the prevalence of respiratory symptoms and lung function in children have yielded mixed results, partly related to differences in study design, exposure assessment, confounder selection and data analysis. We assembled respiratory health and exposure data for >45,000 children from comparable cross-sectional studies in 12 countries. 11 respiratory symptoms were selected, for which comparable questions were asked. Spirometry was performed in about half of the children. Exposure to air pollution was mainly characterised by annual average concentrations of particulate matter with a 50% cut-off aerodynamic diameter of 10 μm (PM(10)) measured at fixed sites within the study areas. Positive associations were found between the average PM(10) concentration and the prevalence of phlegm (OR per 10 μg·m(-3) 1.15, 95% CI 1.02-1.30), hay fever (OR 1.20, 95% CI 0.99-1.46), bronchitis (OR 1.08, 95% CI 0.98-1.19), morning cough (OR 1.15, 95% CI 1.02-1.29) and nocturnal cough (OR 1.13, 95% CI 0.98-1.29). There were no associations with diagnosed asthma or asthma symptoms. PM(10) was not associated with lung function across all studies combined. Our study adds to the evidence that long-term exposure to outdoor air pollution, characterised by the concentration of PM(10), is associated with increased respiratory symptoms.     

Even low levels of ambient air pollutants are associated with increased emergency department visits for hypertension

Background

Numerous studies have reported associations between air pollution and cardiovascular diseases. While several studies illustrate that exposures to air pollutants can elevate blood pressure, few have evaluated the clinical relevance of this relationship. Hence, we aimed to explore the associations between daily concentrations of several air pollutants and emergency department visits for hypertension.

Methods

Odds ratios (ORs) for emergency department visits for hypertension in Edmonton, Canada, from April 1992 to March 2002 were associated with pollutant levels (CO, NO₂, SO₂, O₃, and particulate matter [PM] < 10 microns [PM₁₀] and < 2.5 microns [PM_2.5] in aerodynamic diameter, respectively) by means of a case-crossover technique with time-stratified strategy to define controls. The analysis was performed for all (N = 5365), male (N = 2069), and female (N = 3296) patients and for six air pollutants lagged by 0 to 9 days. ORs and their 95% confidence intervals (CIs) were reported for an increase in an interquartile range (IQR) for each pollutant.

Results

We observed associations for all patients and levels of NO₂ (IQR = 12.8 parts per billion; OR, 1.06; 95% CI, 1.00-1.12), SO₂ (IQR = 2.3 parts per billion; OR, 1.04; 95% CI, 1.00-1.08), and PM₁₀ (IQR = 15.0 μg/m³; OR, 1.06; 95% CI, 1.01-1.11) for lag day 3, as well as for PM₁₀ (IQR = 15.0 μg/m³; OR, 1.06; 95% CI, 1.01-1.11) and PM_2.5 (IQR = 6.2 μg/m³; OR, 1.07; 95% CI, 1.01-1.11) for lag day 6.

Conclusions

These findings support the contention that ambient pollution can produce clinically meaningful increases in blood pressure.     

Predictors of asthma severity in the elderly: results of a community survey in Northeast England.

A number of risk factors for the development and severity of asthma in childhood are known. Particularly, there is information on allergens, excessive use of beta2- agonists, and indoor environmental pollutants. Similar information on elderly patients is lacking. We examined the risk factors for current asthma and for the severity of asthma in 95 elderly subjects (>65 years old) compared to 274 elderly subjects with obstructive spirometry who did not have asthma as defined by the following criteria: symptoms of episodic wheeze, cough, or chest tightness and forced expiratory volume in 1 sec/vital capacity (FEV1/VC) <70% with >15% or 200 mL reversibility in FEV1 to 200 microg salbutamol given from a metered-dose inhaler. The severity of airflow limitation was graded on the basis of the FEV1/VC ratio as mild (60%-70%), moderate (40%-60%), and severe (<40%). Asthma history was collected using the Medical Research Council respiratory questionnaire and a follow-up postal questionnaire. Data were analyzed using multiple logistic regression and the overall goodness-of-fit of the model was checked using the Hosmer-Lemeshow (HL) statistic. History of allergy (to one or more of the following allergens: cat, house dust, or grass or tree pollen) (odds ratio [OR] 25; 95% confidence interval [CI] 13-51; p = 0.0001) and history of childhood wheeze (OR 8; 95% CI 4-9; p = 0.004) were strong predictors of current asthma. Duration of wheezing, smoking history, indoor heating, history of working in coal mines, and sex were not predictors (HL 6.75, degrees of freedom [df] = 8, p = 0.56). Use of >4 puffs of salbutamol/ day (OR 5.3; 95% CI 2-14; p = 0.005), more than 10 years of asthma symptoms (OR 4.2; 95% CI 4.1-36.2; p = 0.0001), and >500 mL reversibility in FEV1 (OR 4.2; 95% CI 1.2-14.3; p = 0.05) were independent predictors of moderate to severe asthma. History of atopy was the strongest predictor of asthma in the elderly population studied. Indoor heating, presence of pets at home, sex, smoking history, and history of working in coal mines were not predictors of asthma. The severity of asthma as assessed by measurement of airflow limitation was related to the frequency of use of beta2-agonists, duration of symptoms of asthma, and increased reversibility of FEV1 to beta2-agonist.     

An Epidemiological Study of Asthma Prevalence and Related Factors Among Young Adults

Asthma and related factors were assessed by mailed questionnaires among 2041 young adult participants in a smoking prevention project in California in 1993. Hispanics had lower prevalence of physician-reported asthma when compared to blacks and whites. Blacks were significantly more likely to be hospitalized or visit emergency rooms because of asthma or wheezing. After adjusting for sex, race, and educational level, family history of asthma was strongly associated with subjects' asthma (odds ratio = 3.1, 95% CI: 2.4-4.3 for physician-reported asthma; OR = 3.3, 95% CI: 2.4-4.5 for current asthma). Exposure to parental smoking (both parents smoked more than half a pack of cigarettes a day) during childhood (reported when participants were in grade 7) was significantly associated with physician-reported asthma (OR = 2.9, 95% CI: 1.6-5.6) and current asthma (OR = 3.3, 95% CI: 1.7-6.4). The study also found that self-reported mold growth at home was significantly associated with asthma (OR = 2.0, 95% CI: 1.2-3.2). After adjusting for cigarette smoking and demographic variables, use of crack cocaine was marginally significantly associated with current asthma (OR = 2.3, 95% CI: 1.0-5.2), but not with physician-reported asthma (OR = 1.5, 95% CI: 0.7-3.3).     

Obesity and Its Relationship with Asthma Prevalence and Severity in Adolescents from Southern Brazil

Obesity has been pointed out as a risk factor for higher prevalence of asthma and asthma-related symptoms in adolescents. The objective was to evaluate the relationship between the prevalence of asthma and obesity in adolescents living in Santa Maria and surroundings (state of Rio Grande do Sul, southern Brazil), applying the International Study of Asthma and Allergies in Childhood (ISAAC) protocol. A total of 4,010 of 6,123 schoolchildren, 13 to 14 years of age, enrolled in the ISAAC phase III protocol (asthma core questionnaire) and were nutritionally evaluated: height, weight, and triceps skinfold (TSF) measurements. Prevalence of asthma (wheeze in the last 12 months) and prevalence of severe asthma (two or more affirmative responses to: more than 4 acute attacks of asthma, speech disturbance, sleep disturbance, wheezing with exercise) were evaluated and compared according to their nutritional status: obese and non-obese. Obese adolescents were defined by body mass index (BMI, in kg/m²) ≥85th percentile and TSF ≥85th percentile. Obese and non-obese groups were compared for prevalence of asthma and asthma severity using the Chi-square test and odds ratio (OR) with 95% confidence interval. Analyzing all adolescents, we observed a significant positive relationship between the prevalence of obesity and affirmative responses to “wheeze ever” (OR = 1.28; 95% CI 1.08-1.52), “wheezing with exercise” (OR = 1.36; 95% CI 1.11-1.66), “asthma ever” (OR = 1.29; 95% CI 1.03-1.62), and severe asthma (OR = 1.55; 95% CI 1.12-2.14). Among the boys, there was a significant positive association between obesity and “wheeze ever” (OR = 1.49; 95% CI 1.13-1.86). In girls, there was a significant positive relationship with “asthma ever” (OR = 1.38; 95% CI 1.01-1.88) and “wheezing with exercise” (OR = 1.36; 95% CI 1.11-1.66). This cross-sectional study with adolescents living in the southern region of Brazil showed that there is a positive association between obesity and prevalence of asthma symptoms and asthma severity, a finding mainly confined to girls.     

Increased asthma medication use in association with ambient fine and ultrafine particles.

The association between particulate air pollution and asthma medication use and symptoms was assessed in a panel study of 53 adult asthmatics in Erfurt, Germany in winter 1996/1997. Number concentrations of ultrafine particles, 0.01-0.1 microm in diameter (NC(0.01-0.1), mean 17,300 x cm(-3), and mass concentrations of fine particles 0.01-2.5 microm in diameter (MC(0.01-2.5)), mean 30.3 microg x m(-3), were measured concurrently. They were not highly correlated (r=0.45). The associations between ambient particle concentrations and the prevalence of inhaled beta2-agonist, corticosteroid use and asthma symptoms, were analysed separately with logistic regression models, adjusting for trend, temperature, weekend, holidays, and first order autocorrelation of the error. Cumulative exposures over 14 days of ultrafine and fine particles were associated with corticosteroid use. Beta2-agonist use was associated with 5-day mean NC(0.01-0.1) and MC(0.01-2.5). The prevalence of asthma symptoms was associated with ambient particle concentrations. The results suggest that reported asthma medication use and symptoms increase in association with particulate air pollution and gaseous pollutants such as nitrogen dioxide.     

A comprehensive analysis of adverse obstetric and pediatric complications in women with asthma

RATIONALE: Previous studies have raised concern that women with asthma have increased risks of adverse obstetric and pediatric complications, but these have generally been underpowered. OBJECTIVES: To quantify risks of major adverse pregnancy outcomes and obstetric complications in women with and without asthma. METHODS: We extracted information on 281,019 pregnancies from the Health Improvement Network database between 1988 and 2004. We analyzed the data using logistic regression. MEASUREMENTS AND MAIN RESULTS: In 37,585 pregnancies of women with asthma compared with 243,434 pregnancies of women without asthma, risks of stillbirth and therapeutic abortion were similar; however, the risk of miscarriage was slightly higher (odds ratio [OR], 1.10; 95% confidence interval [CI], 1.06-1.13). Risks of most obstetric complications (placental abruption, placental insufficiency, placenta previa, preeclampsia, hypertension, gestational diabetes, thyroid disorders in pregnancy, and assisted delivery) were not higher in pregnancies of women with asthma compared with those without asthma, with the exception of increases in antepartum (OR, 1.20; 95% CI, 1.08-1.34) or postpartum (OR, 1.38; 95% CI, 1.21-1.57) hemorrhage, anemia (OR, 1.06; 95% CI, 1.01-1.12), depression (OR, 1.52; 95% CI, 1.36-1.69), and caesarean section (OR, 1.11; 95% CI, 1.07-1.16). Risks of miscarriage, depression, and caesarean section increased moderately in women with more severe asthma and previous asthma exacerbations. CONCLUSIONS: We found some increased risks in women with asthma that need to be considered in the future; however, our results indicate that women with asthma have similar reproductive risks compared with women without asthma in the general population for most of the range of outcomes studied.     

Role of spirometry and exhaled nitric oxide to predict exacerbations in treated asthmatics

OBJECTIVE: To evaluate the complementary roles of exhaled nitric oxide (NO) and spirometry to predict asthma exacerbations requiring one or more tapering courses of systemic corticosteroids. METHODS: We prospectively studied 44 nonsmoking asthmatics (24 women) aged 51 +/- 21 years (mean +/- SD) who were clinically stable for 6 weeks and receiving 250 mug of fluticasone/50 mug of salmeterol or equivalent for 3 years. Total exhaled NO (FENO), small airway/alveolar NO (CANO), large airway NO flux (J'awNO), and spirometry were measured. RESULTS: Baseline FEV(1) was 2.1 +/- 0.7 L, 70 +/- 20% of predicted after 180 mug of albuterol. Twenty-two of 44 asthmatics had one or more exacerbations over 18 months, 16 of 22 asthmatics had two exacerbations, and 6 of 22 asthmatics were hospitalized, including 1 asthmatic with near-fatal asthma. When baseline FEV(1) was 76% of predicted, exacerbations occurred only in 2 of 13 asthmatics (15%) [p = 0.003, chi(2)]. Using a receiver operating characteristic (ROC) curve for first exacerbation, the area under the curve was 0.67 with cutoff FEV(1) of 76% of predicted (sensitivity, 0.91; specificity, 0.50; positive predictive value, 0.65; negative predictive value, 0.85; positive likelihood ratio [LR(+)], 1.8; negative likelihood ratio [LR(-)], 0.18). When baseline FENO was >/= 28 parts per billion (ppb), exacerbations occurred in 13 of 17 asthmatics (76%); if baseline FENO was < 28 ppb, exacerbations occurred in only 9 of 27 asthmatics (33%) [p = 0.005, chi(2)]. Using the ROC curve for first exacerbation, the area under the curve was 0.71 with FENO cutoff point of 28 ppb (sensitivity, 0.59; specificity, 0.82; positive predictive value, 0.77; negative predictive value, 0.87; LR(+), 3.3; LR(-), 0.5). Independent of baseline FEV(1), FENO >/= 28 ppb increased the relative risk (RR) for exacerbation by 3.4 (95% confidence interval [CI], 1.3 to 9.1; Mantel-Haenszel, p = 0.007). An abnormal increase in CANO increased RR by 3.0 (95% CI, 0.9 to 9.9; p = 0.04), and abnormal J'awNO increased RR by 2.4 (95% CI, 1.0 to 5.6; p = 0.04). Independent of baseline FENO, FEV(1) /= 28 ppb and FEV(1) 76% of predicted had a 0% probability of exacerbation. CONCLUSION: Combining FENO and FEV(1) percentage of predicted can stratify risk for asthma exacerbation.     

Diet among Japanese female university students and asthmatic symptoms, infections, pollen and furry pet allergy

OBJECTIVES: To study associations between diet, respiratory symptoms and allergy among female university students in Japan. METHODS: A standardised questionnaire was distributed to students in Kobe and Kamakura (N=153). Multiple logistic/linear regression was applied, controlling for age, smoking, heredity and diet. RESULTS: Totally 15.7% reported doctor-diagnosed asthma, 3.3% current asthma medication, 56.9% pollen allergy, 15.7% cat allergy, 11.1% dog allergy, 25.0% wheeze, 24.2% daytime and 9.3% nocturnal attacks of breathlessness. Meat consumption was related to wheeze (OR=2.00; 95% CI 1.12-3.60) and respiratory infections (OR=2.10; 95% CI 1.08-4.09). Fish consumption was related to less respiratory infections (OR=0.49; 95% CI 9.28-0.86), seafood to less pollen allergy (OR=0.66; 95% CI 0.44-0.99), and milk consumption to less daytime breathlessness (OR=0.72; 95% CI 0.55-0.95). Fast food consumption was related to wheeze (OR=1.89; 95% CI 1.23-2.91), daytime breathlessness (OR=1.50; 95% CI 1.00-2.28) and pollen allergy (OR=1.69; 95% CI 1.07-2.65). In total, 23.0% used butter, 21.7% margarine, 40.1% olive oil and 55.3% rapeseed oil. Those consuming butter (OR=2.65; 95% CI 1.11-6.32) and rapeseed oil (OR=2.35; 95% CI 1.03-5.38) had more wheeze. Those consuming margarine had more nocturnal breathlessness (OR=4.40; 95% CI 1.42-13.7). An asthma symptom score was related to fast food (p<0.05) and margarine consumption (p<0.01). Factor analysis identified five dietary patterns. A pattern including fast food, juice and soft drinks was related to wheeze and respiratory infections. CONCLUSION: Fish, seafood and milk consumption seems to be beneficial, while butter, margarine, rapeseed oil, fast food and soft drinks could be risk factors for allergy and respiratory health.