Setting definitions of childhood asthma in epidemiologic studies

Abstract

Background The definitions of childhood asthma differ among epidemiological studies. We aimed to compare the diagnostic accuracy and agreement of previous asthma definitions and to evaluate questionnaire‐driven asthma definition patterns. Methods Data on 808 participants aged 7‐12 years from 20 schools were analyzed. Asthma definitions based on symptoms assessed by questionnaire, parent‐reported medical asthma diagnosis, current use of asthma medication, airway reversibility after bronchodilatation, and increased (≥35 ppb) levels of exhaled nitric oxide (eNO) were compared with a gold standard (medical diagnosis of asthma with asthma symptoms in the past 12 months and/or airway reversibility). Concordance was assessed by Cohen's kappa. Data‐driven analysis was applied to the questionnaire, and six scores were determined “asthma,” “rhinitis,” “cough,” “non‐specific respiratory symptoms,” “treated asthma,” and “uncontrolled asthma.” Tree decisions were built using these scores. Results Definitions of asthma based on respiratory symptoms, airway reversibility, and parent‐reported medical diagnosis had a low sensitivity but high specificity. Agreement between reported and objective measures was poor. Parent‐reported medical asthma diagnosis, but not reversibility or eNO, was able to predict questionnaire‐driven symptom patterns. Decision trees indicated that those with recent non‐specific respiratory symptoms had a higher probability of positive bronchodilation. Conclusion A standardized operational definition of asthma should include a composite score based on reported asthma medical diagnosis, symptoms, and lung function.

Development and validation of exhaled breath condensate microRNAs to identify and endotype asthma in children

“…Asthma was defined using a gold standard definition based on a positive bronchodilation (BD) defined as at least 12% and over 200mL increase in FEV1 after inhaling 400 μg of salbutamol; or had self-reported medical diagnosis of asthma with symptoms (wheezing, dyspnea or dry cough) in the previous year [12]. Additionally, different asthma phenotypes were created based on classical definitions that involved several asthma features and traits [13]: i) allergic asthma, defined by positive skin prick tests (SPT); ii) eosinophilic asthma, defined by exhaled nitric oxide above 35 ppb; iii) obese asthma, defined by overweight or obesity; iv) persistent asthma, defined by current use of anti-asthma medication; v) symptomatic asthma, defined by current symptoms; vi) positive bronchodilation with asthma symptoms (BD+S+); vii) positive bronchodilation without asthma symptoms (BD+S-); and viii) negative bronchodilation with asthma symptoms (BD-S+).…”

The Influence of Eating at Home on Dietary Diversity and Airway Inflammation in Portuguese School-Aged Children

“…In fact, in the present study, among children with higher eNO ( n = 75), only 18 have asthma defined by self-reported medical diagnosis with reported symptoms (wheezing, dyspnea, or dry cough) occurring in the past 12 months or positive bronchodilation (data not shown). Moreover, our group previously showed that eNO had very low diagnostic accuracy for asthma [ 53 ]. Nonetheless, the mechanisms that led its production, either to be a mediator of cell damage or a mechanism of defense under pro-oxidant environments, are not completely understood [ 46 ].…”

Dietary Acid Load: A Novel Nutritional Target in Overweight/Obese Children with Asthma?

“…However, compared to direct measures, self-reported methods may be able to represent the type of activity that is undertaken [47]. Although current asthma was not diagnosed by a physician, the used criteria in this study included a standardized operational definition of asthma supported by objective lung function measurements [48]. Another limitation of our study is the fact that food intake was evaluated using questionnaires, which can lead to bias.…”