Diagnosis Of Asthma In Children Research Articles

Spirometry-Adjusted Fraction of Exhaled Nitric Oxide Allows Asthma Diagnosis in Children, Adolescents, and Young Adults.

Recently, it has been proved that fractional exhaled nitric oxide (FENO) results are in disagreement with other measurements of asthma control. The objective of this work is to present and validate new lung function/lung inflammation ratios. This is a retrospective, cross-sectional study in which we evaluated data from medical documentation of 1,529 pediatric and adolescent subjects and a small number (2% of the studied population) of young adults, who presented symptoms suggestive of asthma (age range 4-24 y). We are the first to analyze results obtained in this manner (before the introduction of controlled medication): FENO, spirometry, specific resistance of the airways, diagnosis of allergic diseases, and allergen sensitization (specific immunoglobulin E results). Cut-off points for the new indicators allowed us to diagnose asthma in the study participants: for FVC/FENO ratio, 0.17 L/ppb; for FEV1/FENO ratio, 0.15 L/ppb; for forced expiratory flow during the middle half of the FVC maneuver (FEF25-75%)/FENO ratio, 0.16 L/s/ppb; for FENO/FVC ratio, 11.00 ppb/L; for FENO/FEV1 ratio, 12.53 ppb/L; and for FENO/FEF25-75% ratio, 11.81 ppb/L/s. Only the ratios described above were closely correlated with the diagnosis of asthma and with one another. They significantly differed between subjects with asthma and healthy subjects as well as between females and males. Only FEF25-75%/FENO and FENO/FEF25-75% values were significant predictors of any sensitization in the studied subjects. We found higher sensitivity than specificity and higher positive predictive value than negative predictive value for FVC/FENO, FEV1/FENO, and FEF25-75%/FENO and found a mirror image for reverse parameters. However, the positive predictive values and negative predictive values were not clearly convincing with respect to diagnostic accuracy in the case of the new parameters proposed. We propose new lung function/lung inflammation ratios by which it may become possible to diagnose asthma in children and adolescents on the basis of a subject's spirometry and FENO measurements. We believe that our ratios are only supportive of the universally used parameters in the process of diagnosing asthma. (ClinicalTrials.gov registration NCT01805635.).

Methacholine challenge testing is superior to the exercise challenge for detecting asthma in children

BackgroundExercise-induced bronchoconstriction occurs in a large proportion of children with asthma. ObjectiveTo compare the predictive value of methacholine challenge testing (MCCT) and the exercise treadmill challenge (ETC) for detecting asthma in children with postexercise symptoms. MethodsThis was a prospective study of children 10 to 18 years old with postexercise symptoms. During asthma diagnosis, they underwent MCCT and ETC. There were 2 study visits. All subjects underwent ECT at visit 1 and MCCT 1 week later at visit 2. ResultsOne hundred one children were included; 62.9% had a history of atopy, and asthma was confirmed in 43.6%. MCCT showed 90.9% sensitivity, 82.5% specificity, 80.0% positive predictive value, and 92.2% negative predictive value; the respective values for ECT were 77.3%, 68.4%, 65.4%, and 79.6%. Positive MCCT results showed significantly higher sensitivity and higher positive predicative value in the diagnosis of asthma in children with postexercise symptoms compared with a 10% decrease in forced expiratory volume in 1 second for ECT (P = 0.034). Conducting MCCT during asthma diagnosis confirmed asthma in an additional 24.3% of children with exercise-induced symptoms. With a cutoff level at 17% of forced expiratory volume in 1 second for ECT, the discrepancy was decreased and reasonable values for sensitivity, specificity, positive predictive value, and negative predictive value were attained (61.0%, 77.1%, 69.4%, and 69.8%, respectively). ConclusionA large number of school children with asthma and postexercise symptoms could have positive MCCT and negative ECT findings. Untreated asthma in children with exercise-induced bronchoconstriction could cause them to be discharged from physical education classes. Trial Registrationwww.ClinicalTrials.gov, identifier NCT01798823.

Modification of additive effect between vitamins and ETS on childhood asthma risk according to GSTP1 polymorphism : a cross -sectional study

BackgroundAsthma is characterized by airway inflammation, and bronchial airways are particularly susceptible to oxidant-induced tissue damage.ObjectiveTo investigate the effect of dietary antioxidant intake and environmental tobacco smoke (ETS) on the risk of childhood asthma according to genotypes susceptible to airway diseases.MethodsThis cross-sectional study included 1124 elementary school children aged 7–12 years old. Asthma symptoms and smoking history were measured using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Intake of vitamin A (including retinol and β-carotene), C, and E was measured by a semi-quantitative food frequency questionnaire (FFQ). GSTP1 polymorphisms were genotyped from peripheral blood samples.ResultsETS was significantly associated with presence of asthma symptoms (adjusted odds ratio [aOR], 2.48; 95 % confidence interval [CI], 1.29–4.76) and diagnosis (aOR, 1.91; 95 % CI, 1.19–3.06). Dietary antioxidant intake was not associated with asthma symptoms, although ETS plus low vitamin A intake showed a significant positive association with asthma diagnosis (aOR, 2.23; 95 % CI, 1.10–4.54). Children with AA at nucleotide 1695 in GSTP1 who had been exposed to ETS and a low vitamin A intake have an increased risk of asthma diagnosis (aOR, 4.44; 95 % CI,1.58–12.52) compared with children who had not been exposed to the two risk factors. However, ETS exposure and low vitamin A intake did not significantly increase odds of asthma diagnosis in children with AG or GG genotypes.ConclusionLow vitamin A intake and ETS exposure may increase oxidative stress and thereby risk for childhood asthma. These relationships may be modified by gene susceptibility alleles of GSTP1.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-015-0093-0) contains supplementary material, which is available to authorized users.

Early predictors of asthma and allergy in children: the role of epigenetics.

Asthma and allergic diseases are among the most prevalent chronic noncommunicable diseases of childhood. Although epidemiologic studies suggest that asthma begins in the preschool years, the lack of firm diagnostic criteria to distinguish children who will wheeze only transiently during early-life lower respiratory illnesses from children who will wheeze persistently and develop asthma prevents pinpointing the time at which disease truly begins. Epigenetic mechanisms link gene regulation to environmental cues and developmental trajectories. This article reviews, the search for epigenetic predictors of asthma and/or allergy that can be identified already at birth and/or in early life. DNA methylation signatures associated with asthma and/or allergy at birth, and time-dependent DNA methylation signatures associated with allergic disease phenotypes in early life have been identified. The identification of early epigenetic predictors of allergic diseases points to a potential role of epigenetic mechanisms in regulating the inception of and the susceptibility to these diseases. Predictive signatures to more accurately estimate a child's risk for asthma and allergy may improve childhood asthma diagnosis. Moreover, understanding the biological implications of these signatures may help elucidate novel disease pathways and endotypes.

The clinical utility of reticular basement membrane thickness measurements in asthmatic children

Objective: Reticular basement membrane (RBM) thickness is one of the pathological features of asthma and can be measured in endobronchial biopsies. We assessed the feasibility of endobronchial biopsies in a routine clinical setting and investigated the clinical value of RBM thickness measurements for asthma diagnosis in children. Methods: We included all children who underwent bronchoscopy with endobronchial mucosal biopsies for clinical reasons and divided them into three subgroups: (1) no asthma, (2) mild–moderate asthma, and (3) problematic severe asthma. Results: In 152/214 (71%) patients, mean age 9.5 years (SD 4.6; range 0.1–18.7) adequate biopsies were retrieved in which RBM thickness could be measured. Mean (SD) RBM thickness differed significantly among children without asthma, with mild–moderate asthma, and with problematic severe asthma (p = 0.04), 4.68 (1.24) µm, 4.56 (0.89) µm, and 5.21 (1.10) µm respectively. This difference disappeared after adding exhaled nitric oxide to the multivariate model. Conclusions: This study confirms the difference in RBM thickness between children with and without asthma and between asthma severities in a routine clinical care setting. However, quantifying the RBM thickness appeared to have no added clinical diagnostic value for asthma in children.

Asma en la infancia: controversias que conllevan al subdiagnóstico

El asma es la enfermedad crónica más frecuente en la niñez y conduce a múltiples complicaciones, fenómeno que en la actualidad representa un problema de salud pública. El reporte de síntomas bronco-obstructivos es mucho mayor que el diagnóstico médico de asma durante la infancia, hecho que sugiere que hay una tendencia a no reconocer que los niños en esta edad sufren de esta enfermedad y por tanto eventualmente se ocasiona retraso en su tratamiento. El rechazo a clasificar a los pacientes como asmáticos, la falta de un consenso diagnóstico, los múltiples fenotipos, la flexibilidad de las escalas de severidad y el desconocimiento del asma en la infancia como una enfermedad intermitente pero potencialmente grave, son factores del manejo médico que podrían favorecer una alta morbilidad. Esta revisión plantea la necesidad de ser más contundentes en el diagnóstico del asma en la infancia, sin caer en retrasos que permitan iniciar un tratamiento oportuno y adecuado.

Time trends in the incidence, prevalence and age at diagnosis of asthma in children.

Current knowledge on the prevalence of asthma is mainly based on cross-sectional questionnaire data. Current population-based data on the incidence of asthma in children are scarce. To study the incidence, prevalence, and age at diagnosis of asthma in children in the Netherlands over the study period 2000-2012. A population-based cohort study was conducted in the Integrated Primary Care Information database. The cohort consisted of 176,516 children (379,536 personyears (PY) of follow-up), aged 5-18 years between 2000 and 2012. All medical records of children with physician diagnosed asthma were validated. Incidence rates, annual percent change (APC), and prevalence for asthma were calculated. Influence of age and gender on incidence rates and change in age at diagnosis were studied. We identified an asthma cohort of 14,303 children with 35,118 PY. The overall incidence rate was 6.7/1000 PY (95% CI, 6.45-6.97). Until 2008, the incidence rate was significantly increasing (APC 5.79 (95% CI 1.43-10.34); from 2008 onwards, a non-significant decrease was observed (APC -12.16 (95% CI -23.07 to 0.28). Incidence for girls was lower than for boys, this difference decreased with increasing age. (p < 0.001) Overall, the age at diagnosis increased over calendar time and was lower for boys. (linear trend p < 0.001). Our population-based cohort study observed an incidence rate of 6.7 per 1000 PY of physician-diagnosed asthma in children in the Netherlands over 2000-2012. The asthma incidence rate was increasing until 2008. Further studies are needed to confirm the decrease in asthma incidence rate from 2008 onwards.

Is there an association between acetaminophen use and the risk of asthma?

Evidence-Based Answer There is a correlation between acetaminophen use and a diagnosis of asthma in children and adults. There is also a correlation between prenatal use of acetaminophen and the risk of asthma in children. This risk appears to increase with dose (SOR: B, meta-analysis of observational studies and individual observational studies). Study structures, however, do not allow a cause-and-effect assessment.

The Association Between Adverse Childhood Experiences in the Home and Pediatric Asthma

BackgroundNumerous studies suggest that psychosocial factors may contribute to pediatric asthma. ObjectiveTo examine the relationship between single and cumulative Adverse Childhood Experiences (ACEs), a measure of household dysfunction, on parent report of lifetime asthma among children. MethodsThis cross-sectional study used 2011-2012 National Survey of Children’s Health data, a nationally representative sample of children 0 to 17 years (n = 92,472). The main exposure was parent/guardian report of 6 ACE exposures (for example; witnessing domestic violence). The relationship between ACE exposures and parent-reported diagnosis of childhood asthma was examined using multivariable logistic regression, controlling for demographic, socioeconomic and behavioral covariates. ResultsOverall asthma prevalence was 14.6%. Exposure to any ACE was 29.2%. Increased number of ACE exposures was associated with increased odds of asthma. In the adjusted model, the odds of reporting asthma were 1.28 (95% confidence interval [CI] 1.14, 1.43) for those reporting one ACE, and increased to 1.73 (95% CI 1.27, 2.36) for those with 4 ACEs and 1.61 (95% CI 1.15, 2.26) for those with 5 or 6 ACEs compared to those with no ACE exposures. Effects were moderated by Hispanic ethnicity. Hispanic children exposed to 4 ACEs had a 4.46 times increase in lifetime asthma (95% CI 2.46, 8.08); white children had a 1.19 times increase (95% CI 0.80, 1.79) compared to those exposed to zero ACEs. ConclusionsThis study further supports the growing evidence for the biopsychosocial model of asthma onset. Future studies should examine the association between ACEs and specific asthma-related health outcomes.

Bronchial asthma symptoms and diagnosis prevalence in children at the Grodno region as a representative of the Republic of Belarus according to the ISAAC program (phase I)

The aim. A prevalence of symptoms and bronchial asthma diagnosis in children have been studied at the Republic of Belarus using an example of the Grodno region. Methods. The results were adjusted to gender and were compared to those from other regions according to the ISAAC program (phase I). Results. One thousand nine hundred and eighty five school children were questioned. It was established that bronchial asthma symptoms are widespread in school children at the Grodno region. Conclusion. These results obtained under ISAAC program (phase I) are in line with the results of similar studies conducted at other regions.

Alleviating anxiety after a child's asthma diagnosis

PARENTAL CONCERNS Steve Holmes and Jane Scullion consider how best to address parental worries after their child is diagnosed with asthma

Trends in the age of diagnosis of childhood asthma

The cause of rising asthma incidence over time remains unexplained. Examining trends in the age of diagnosis across successive birth cohorts may offer insights into asthma etiology. To examine trends in the age at asthma diagnosis and the age and proportion of children hospitalized at first asthma diagnosis in Ontario, Canada. Eight consecutive birth cohorts of children (1993-2000) were observed using administrative data from a universal health insurance plan in Ontario, Canada (population 13 million). Trends in the need for hospitalization and age at asthma diagnosis were examined with descriptive and survival analyses. The records of 1,059,511 children were examined, of whom 201,958 developed asthma in the first 8 years of life, with an average cumulative incidence of 19.1%. Mean age at asthma diagnosis decreased from 4.7 ± 1.5 years in birth year 1993 to 2.6 ± 2.0 years in birth year 2000 (P < .0001), with a higher adjusted risk of asthma diagnosis (hazard ratio, 6.7; 95% CI, 6.5-6.9) in the first 3 years of life for children born after 1996 versus children born in the period 1993 to 1995 (hazard ratio, 1.4; 95% CI, 1.3-1.4). The proportion of children hospitalized at asthma diagnosis stayed stable while the age at first asthma hospitalization decreased over time (P < .0001). This study demonstrates a significant increase in asthma incidence and a decrease in the age of asthma diagnosis across multiple birth cohorts. Changes in asthma incidence over time are primarily explained by variations in asthma rates in children younger than 3 years.

Association between low vitamin D levels and the diagnosis of asthma in children: a systematic review of cohort studies.

BackgroundThere is conflicting evidence about the association between low vitamin D levels in children and development of asthma in later life. The objective of this study was to systematically review the evidence for an epidemiological association between low serum levels of vitamin D and the diagnosis of asthma in children.MethodsWe used the Cochrane methodology for conducting systematic reviews. The search strategy included an electronic search of MEDLINE and EMBASE in February 2013. Two reviewers completed, in duplicate and independently, study selection, data abstraction, and assessment of risk of bias.ResultsOf 1081 identified citations, three cohort studies met eligibility criteria. Two studies found that low serum vitamin D level is associated with an increased risk of developing asthma late in childhood, while the third study found no association with either vitamin D2 or vitamin D3 levels. All three studies suffer from major methodological shortcomings that limit our confidence in their results.ConclusionsAvailable epidemiological evidence suggests a potential association between low serum levels of vitamin D and the diagnosis of asthma in children. High quality studies are needed to reliably answer the question of interest.

Validación de un cuestionario diagnóstico de asma en niños y adultos para estudios epidemiológicos

Asthma is a chronic airway inflammatory disease, for identification in the population epidemiological studies are required. To validate a questionnaire of asthma diagnosis in children and adults. A prolective, cross-sectional, homodemic and multicenter study was done in which a questionnaire of asthma for children and adults was subjected to a validation process was developed from November 2012 to February 2014, 300 patients, 150 children and 150 adults of both sexes, obtained from the Allergy department. The questionnaire was applied to adults from 13 years of age and to parents who have children age 12 and under. Each question was assigned a score as the sum of the points according to symptoms, when it reached a score equal to or greater than 0.75, asthma was diagnosed. The questionnaire of asthma was applied in adult population 13-70 years of age and fathers with children was 2-12 years old. The tests applied to questionnaire responses showed adults and children in good agreement in the test and retest interobserver agreement, this being substantial to almost perfect. The tests applied to criterion validity for both questionnaires showed a sensitivity of 90% in > 12 y, and 90 % in children, and specificity of 91% and 90%, respectively PPV 92% and NPV 90% in > 12 y and 90% PPV and 90% NPV in children. The criteria for content validity and expression are properly met. The homogeneity test Cronbach's alpha was 0.7. The questionnaire for diagnosis of asthma in adults and children has good intra- and interobserver agreement, with high sensitivity and specificity in the criterion validity.

Chest Radiography in Supporting the Diagnosis of Asthma in Children with Persistent Cough

Objective: To establish whether chest radiographic findings suggestive of lower airway obstruction (LAO) disease support the diagnosis of asthma in pediatric patients with persistent cough in an outpatient setting. Methods: 180 patient charts were reviewed. The patients were children aged 1 to 18 years referred over a 3–year period to a pediatric pulmonary subspecialty clinic for evaluation of cough lasting ≥ 4 weeks. Chest radiographic images obtained after the initial evaluation of 90 patients diagnosed with cough–variant asthma and 90 patients diagnosed with persistent cough from nonasthma origins were compared with radiologic findings of a control group consisting of patients with a positive tuberculin skin test and no respiratory symptoms. Increased peribronchial markings/peribronchial cuffing and hyperinflation were considered radiographically suggestive findings of LAO disease. Results: Children diagnosed with cough–variant asthma at the initial evaluation had higher rates of chest radiographic findings suggestive of LAO disease (30.00%) than children with persistent cough from other causes (17.80%) or those with a positive tuberculin skin test and no respiratory symptoms (8.16%) (overall P value = 0.0063). They also had higher rates of spirometry abnormalities suggestive of an LAO defect. Children with chest radiographic findings suggestive of LAO disease were found to be younger than those with normal chest radiographic findings (5.0 ± 2.7 years vs 8.6 ± 4.7 years; P < 0.0001). Conclusion: This study suggests that chest radiographic findings indicative of an LAO in correlation with the clinical presentation can support the diagnostic suspicion of asthma, especially in younger children unable to perform spirometry.

Gastroesophageal Reflux Disease Increases Infant Acute Respiratory Illness Severity, but not Childhood Asthma

It is unknown whether gastroesophageal reflux disease (GERD) during infancy affects infant bronchiolitis severity or childhood asthma inception. Four hundred thirty-two infants presenting with acute respiratory illness due to bronchiolitis or upper respiratory infection were studied. The primary exposure was the parental report of a previous GERD diagnosis. Outcomes included bronchiolitis severity at initial presentation and childhood asthma diagnosis at age 4. Infants with parentally reported GERD had a higher bronchiolitis severity score (range=0-12, clinically significant difference=0.5), indicating more severe disease, than infants without reported GERD (median 5.5 [interquartile range 3.5-9.0] among those with reported GERD versus 4.0 [1.0-7.0] among those without, P=0.005). This association persisted after adjusting for infant age, race, gender, and secondhand smoke exposure by a propensity score (adjusted odds ratio [OR] 1.99, 95% confidence interval [CI] 1.14-3.46, P=0.02). The parental report of GERD during infancy was not associated with the parental report of asthma diagnosis at age 4. GERD during infancy may contribute to acute respiratory illness severity, but is not associated with asthma diagnosis at age 4. Future prospective studies are needed to confirm these findings.

Wheezing Symptoms and Parental Asthma Are Associated with a Physician Diagnosis of Asthma in Children with Sickle Cell Anemia

To identify factors associated with asthma associated with increased sickle cell anemia (SCA). Children with SCA (N=187; mean age 9.6years, 48% male) were classified as having "asthma" based on parent report of physician diagnosis plus prescription of asthma medication (n=53) or "no asthma" based on the absence of these features (n=134). Pain and acute chest syndrome (ACS) events were collected prospectively. Multiple variable logistic regression model identified 3 factors associated with asthma: parent with asthma (P=.006), wheezing causing shortness of breath (P=.001), and wheezing after exercise (P<.001). When ≥2 features were present, model sensitivity was 100%. When none of the features were present, model sensitivity was 0%. When only 1 feature was present, model sensitivity was also 0%, and presence of ≥2 of positive allergy skin tests, airway obstruction on spirometry, and bronchodilator responsiveness did not improve clinical utility. ACS incident rates were significantly higher in individuals with asthma than in those without asthma (incident rate ratio 2.21, CI 1.31-3.76), but pain rates were not (incident rate ratio 1.28, CI 0.78-2.10). For children with SCA, having a parent with asthma and specific wheezing symptoms are the best features to distinguish those with and without parent report of a physician diagnosis of asthma and to identify those at higher risk for ACS events. The value of treatment for asthma in the prevention of SCA morbidity needs to be studied.

The significance of atopic disease family history in the diagnosis of asthma in children

There is no specific diagnostic tools or marker for detection of asthma in children.However,A large number of studies have shown that atopic disease and positive family history are the important risk factors.It is helpful for the asthma early diagnosis,proper management and prevention through the analysis of the relationship between childhood asthma and atopic disease as well as positive family history. Key words: Allergic rhinitis; Food allergy; Atopic disease; Asthma

Inflammatory phenotypes underlying uncontrolled childhood asthma despite inhaled corticosteroid treatment: rationale and design of the PACMAN2 study.

BackgroundThe diagnosis of childhood asthma covers a broad spectrum of pathological mechanisms that can lead to similarly presenting clinical symptoms, but may nonetheless require different treatment approaches. Distinct underlying inflammatory patterns are thought to influence responsiveness to standard asthma medication.Methods/designThe purpose of the PACMAN2 study is to identify inflammatory phenotypes that can discriminate uncontrolled childhood asthma from controlled childhood asthma by measures in peripheral blood and exhaled air. PACMAN2 is a nested, case–control follow-up study to the ongoing pharmacy-based “Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects” (PACMAN) study. The original PACMAN cohort consists of children aged 4–12 years with reported use of asthma medication. The PACMAN2 study will be conducted within the larger PACMAN cohort, and will focus on detailed phenotyping of a subset of the PACMAN children. The selected participants will be invited to a follow-up visit in a clinical setting at least six months after their baseline visit based on their adherence to usage of inhaled corticosteroids, their asthma symptoms in the past year, and their age (≥ 8 years). During the follow-up visit, current and long-term asthma symptoms, medication use, environmental factors, medication adherence and levels of exhaled nitric oxide will be reassessed. The following measures will also be examined: pulmonary function, exhaled volatile organic compounds, as well as inflammatory markers in peripheral blood and blood plasma. Comparative analysis and cluster-analyses will be used to identify markers that differentiate children with uncontrolled asthma despite their use of inhaled corticosteroids (ICS) (cases) from children whose asthma is controlled by the use of ICS (controls).DiscussionAsthmatic children with distinct inflammatory phenotypes may respond differently to anti-inflammatory therapy. Therefore, by identifying inflammatory phenotypes in children with the PACMAN2 study, we may greatly impact future personalised treatment strategies, uncover new leads for therapeutic targets and improve the design of future clinical studies in the assessment of the efficacy of novel therapeutics.

Cooking fuels and prevalence of asthma: a global analysis of phase three of the International Study of Asthma and Allergies in Childhood (ISAAC)

Indoor air pollution from a range of household cooking fuels has been implicated in the development and exacerbation of respiratory diseases. In both rich and poor countries, the effects of cooking fuels on asthma and allergies in childhood are unclear. We investigated the association between asthma and the use of a range of cooking fuels around the world. For phase three of the International Study of Asthma and Allergies in Childhood (ISAAC), written questionnaires were self-completed at school by secondary school students aged 13-14 years, 244,734 (78%) of whom were then shown a video questionnaire on wheezing symptoms. Parents of children aged 6-7 years completed the written questionnaire at home. We investigated the association between types of cooking fuels and symptoms of asthma using logistic regression. Adjustments were made for sex, region of the world, language, gross national income, maternal education, parental smoking, and six other subject-specific covariates. The ISAAC study is now closed, but researchers can continue to use the instruments for further research. Data were collected between 1999 and 2004. 512,707 primary and secondary school children from 108 centres in 47 countries were included in the analysis. The use of an open fire for cooking was associated with an increased risk of symptoms of asthma and reported asthma in both children aged 6-7 years (odds ratio [OR] for wheeze in the past year, 1·78, 95% CI 1·51-2·10) and those aged 13-14 years (OR 1·20, 95% CI 1·06-1·37). In the final multivariate analyses, ORs for wheeze in the past year and the use of solely an open fire for cooking were 2·17 (95% CI 1·64-2·87) for children aged 6-7 years and 1·35 (1·11-1·64) for children aged 13-14 years. Odds ratios for wheeze in the past year and the use of open fire in combination with other fuels for cooking were 1·51 (1·25-1·81 for children aged 6-7 years and 1·35 (1·15-1·58) for those aged 13-14 years. In both age groups, we detected no evidence of an association between the use of gas as a cooking fuel and either asthma symptoms or asthma diagnosis. The use of open fires for cooking is associated with an increased risk of symptoms of asthma and of asthma diagnosis in children. Because a large percentage of the world population uses open fires for cooking, this method of cooking might be an important modifiable risk factor if the association is proven to be causal. BUPA Foundation, the Auckland Medical Research Foundation, the Health Research Council of New Zealand, the Asthma and Respiratory Foundation of New Zealand, the Child Health Research Foundation, the Hawke's Bay Medical Research Foundation, the Waikato Medical Research Foundation, Glaxo Wellcome New Zealand, the NZ Lottery Board, Astra Zeneca New Zealand, Hong Kong Research Grant Council, Glaxo Wellcome International Medical Affairs.